Solar Electric Heating Semiconductors Explained! Efficient Simple Powerful Diode chains

[@solarpoweredge]

This topic seems to be broadly misunderstood. It is 100% verified fact by both myself and others (including university researchers) that diode strings can produce more heat (or watt-hours, BTU) from a given solar panel than a bare resistance element. FACTS: 1) Diodes are not "Ohmic" so we cannot use Ohms Formula to calculate I/V/R as one would for resistance element. You could certainly try the maths, but they don't really work for diodes. Interesting exercise at least. 2) Diodes drop a roughly constant voltage (of course it's not perfect and does vary some) 3) Therefore a string of diodes will drop a roughly constant voltage equal to the number of diodes in the chain 4. Therefore diode strings can be matched to the vMP region of a solar panel, and they will drop roughly the same voltage all day, while the current rises in the morning, peaks at noon, and falls back away towards evening. This generates behaviors similar to an maximum power point tracking circuit, although it's not. 5. The diode string operating in the volts-max-power region nearly all day easily beat a bare resistance element. It's obvious - the diode string is holding a nearly steady voltage in the vMP region nearly all day, Volts x Amps x Time = watt-hours, diodes win hands down as they stay at or near vMP. MPPT charge controller does something very similar, no wonder they are so popular... 6) Resistance elements are linear (I/V/R) and will appear in the morning almost like a dead short to the theoretical solar panel producing almost no heat. The diodes will already be warm and operating at a much higher voltage. As the sun comes up, the resistance element will pass more and more current, but at a higher and higher voltage, generating a peak up to noon and falling down towards evening. At some point it will enter the vMP range, but it cannot stay. And current (amperage curve) will also look similar with a "peak" which is the expected behavior. 7. Diode strings connected to a solar panel create a "flatter" voltage curve - verified fact by multiple researchers - and it's obvious on it's own, because the diode is not Ohmic and just drops roughly constant voltage, we don't really see a diode string behaving like a resistance element - in general. 6. Bare resistance elements create a "peaked" voltage curve - again verified and obvious fact - in fact I've been verifying it for years by operating multiple resistance loads directly off my solar panels, heating water and heating my house :) 8. Diode string elements connected to a solar panel produce a "quite flat" voltage curve - again verified and obvious fact - verified by myself and multiple researchers in universities. 9. A diode tends to flow current exponentially versus the voltage flowing across it. 10. A diode tends to pass voltage "logarithmically" versus the current flowing across it. 11. #9 and #10 can help explain why diodes behave so differently and just so happen to match solar electric heating applications well. 12. Diodes aren't perfect, and sometimes do exhibit certain linear behaviors, depending on the type of diode, it's quality etc. but overall behavior matches what I have described in this video and in practice (and reality) in bench tests and real-world testing - not only theory. Diodes do some times have some Ohmic properties, for example due to the connecting wires and leads connecting the diode package. 13. Under changing solar conditions, which is reality, the diode string will far out perform a resistance heating element. The reason is the diodes keep the voltage up near vMP, but the resistance element swings the voltage significantly greatly reducing it's power output as the sun dims or cloud cover blocks the sun. 14. Thinking in terms of watt-hours, a string of diodes will produce lots more watt-hours (which can be thought of as converted to heat) versus a bare resistance element, because the diodes can stay near vMP under changing conditions. But the resistance element reacts noticeably to changing solar conditions, causing voltage to drop significantly and losing overall power. This I have repeatedly verified for years by watching the voltage of solar panels connected to various electric heaters with bare resistance elements. [I may update this list later as time permits] DD

[@trygvetveit4747]

I will lay flat on the total efficiency of this cucit until i have read the papers (i will this is interesting) One qestion: Do we really need to improwe my water heater by and arguable small persent? like from 100% to 101%? Your geniuus idea are not to make the most efficient patio heater Your genious is to tap in to various voltages at extreemly low recictance/Losses Without a Transformer/copper coil !

[@solarpoweredge]

The efficiency gain far exceeds 1%, as the diode string will stay very flat in voltage nearly all day and under changing solar conditions. Resistance element voltage will move quite a lot. Especially under changing solar intensities, the resistance element voltage will drop significantly, whereas the diodes continue to stay relatively flat (near vMP). I will update the list above Yes it's amazing that hot diodes can be used as a power supply with such simple components. Of course the voltage is not perfect, but it's suitable for rough operation of fans or USB charging perhaps. No transformer, no transistors, very cheap too :)

[@JamesParker-x9y]

While more complicated you will get a much higher efficiency improvement by driving a heat pump. Any hearing element (resistive or diode) is only going to be used as a dump load where efficiency isn't critical).

[@FourthWayRanch]

Diodes aren't going to last long as heaters no?

[@solarpoweredge]

@embededfabrication4482 I think they can depending on how they are used. I saw an experiment where diodes heated water and food for 200 days straight from solar. They are fine as long as they don't overheat. My preference is to not heat the diodes any more than necessary, just to be safe. From what I have seen simple diodes can tolerate heat over long periods. And they only cost a few cents to replace. Therefore they are on par with nichrome, but that's my opinion.

[@dougbas3980]

Never thought of heating with my solar panels because I need all the power for freezers/refrigerator/lights/radio/well pump. Your diode method is ingenious. Thank you.

[@solarpoweredge]

@dougbas3980 If you're interested, there is a university research paper called "hot diodes" you can download, they have some interesting tests. Anyway, diodes could be used to dump your excess solar power as heat. I don't know if it would be better than resistance in this case, it depends on how the system is built. Worth looking into!

[@MorgothCreator]

You are absolutely correct, a panel works like a fixed voltage variable current power source, a diode will take advantage of that, because will begin to drain power when the voltage is close to its junction voltage/maximum panel voltage, that way will maintain a fixed voltage on the panels and vary the current in a small voltage variation. Like a previous comment, bipolar transistors with the collector and base shorted are better because they are designed to be mounted on heat sink's.

[@solarpoweredge]

@MorgothCreator Have been using large power rectifier diodes mounted on metal heat sinks, pity I haven't been able to make a video about it. Hopefully I can get that done soon

[@jeffschroeder4805]

Very interesting application of diodes. And I have spent most of my time trying to insure that the diodes didn't get too hot.

[@solarpoweredge]

@jeffschroeder4805 Agreed... in cooking applications I try to keep them from exceeding 100 C. They might go higher, but I hope to avoid burning them out (so far, haven't burned up a single one)

[@arjovenzia]

Yeah, electronics engineers hate a hot diode, it's viewed as lost efficiency, which is a cardinal sin. Using that as a feature... Mind blowing. But does make sense. Thanks for sharing, that's how we learn.

[@carlubambi5541]

Amazing Ben doing this for a while putting diodes in series to get a specific voltage. Each diode drops. -. 6 .7 volts and the waste heat can be used to warm things up if need be. So I used 1n4004 I think rated for 4 amps and 25 volts. Put in 18v and was able to get about 12v at 4 amps I had 12 diodes in series can't Remeber exact voltage but it works when you don't have a voltage regulator or zener diode.. THIS WAS 40+YEARS AGO. NOW I AM A RETIRED CRIPPLED SPARKY AND ENJOY TRYING TO FIX PEOPELS JUNK AND GIVE THEM A NEW LIFE. AND SAVE THE LANDFILL OR SEND THEM OT TO BE RECYCLED PROPERLY.

[@solarpoweredge]

That's great! Glad you're fixing things up and saving them from the landfill, it's a very noble thing to do! It's good to see people experimenting . :)

[@davidahmad6090]

Excelent sir, in effect you have built a really high power zenner diode, you could put these diodes in an isolated sand battery, and use the heat at night time in a bedroom for example. It is best to use a stone ground sand or a sand that does not contain any salts in it, as not to degrade the material of the leads on your diodes. There will be no need for the fan.

[@solarpoweredge]

@davidahmad6090 Thank you sir. Good ideas. Hope to work on the sand battery project during the winter, and and a new diode heater design. It's very hot right now, so I'm focusing on anything that gets "cold"

[@Moonlightshadow-lq4fr]

Indeed it seems to straight forward to be possible. Electricity is something of an amazing entity I think. It can do things that one might not expect even in the simplest of circuits to charge batteries for one instance. You may have discovered a revolutionary way to utilize solar panels and possibly even more.

[@solarpoweredge]

@Moonlightshadow-lq4fr Right on :) 👍 we got to keep looking into it keeping learning more

[@BywaysnoHighways]

Nicely done! You have me headed to my electronics component draw to dig out diodes and see what I have in stock!

[@solarpoweredge]

Thank you! Glad to hear it lol.... have fun with the diodes. Trying to make a cooker device and a diode immersion water heater. If they work another video (or 2) on the way :)

[@arjovenzia]

I'd never thought of this, but you make an excellent point. In my part of the world, 10yo solar panels are cheap/free. It's the regulation hardware n batteries that is expensive. Hot Water is a good way to store energy. Insulated TO-220 packs are avaliable, as are some very beefy smd parts. I've pulled some very interesting ali extrusions from washing machines that have a nice flat mount for packages with a 1" water channel running through it. Ideal. Our off grid cabin has a gas shower, but not enough roof for solar hot water. It would be neat to be able to put the solar panels in the right spots to all heat one tank, without running all that plumbing. Very thought provoking stuff. Thanks for the seed of a very good idea.

[@solarpoweredge]

@arjovenzia Exactly... glad you liked this... any MPPT DC circuit will have significant cost/complexity. If we're just making heat, might as well keep it as Simple and Cheap and DIY friendly as possible.

[@JustaReadingguy]

An easy way to get around the wrong type of packaging is to use power bipolar transistors. The power transistors are packaging is designed to connect to a heat sink. To get the transistor to act like super diode is to connect the collector to the base. So much easier.

[@solarpoweredge]

@JustaReadingguy Hi, good ideas, thanks! been testing those square bridge rectifiers w/ metal cases too

[@Robbedoes2]

Very smart! This is the only correct cheap heating method for solar panels. Although I really like an AC or heat pump combined with a battery and solar. But investment price difference is massive.

[@solarpoweredge]

@Robbedoes2 You might be interested in a related research project... diodes can also work in parallel with nichrome heating elements! Testing that idea now... during midday they regulate the voltage of the parallel element (which does most of the heat), diodes extract the rest of the heat. Can use smaller cheaper diode strings... This is the final part of the picture... in the morning I turn on the diodes, sun comes out. Past 100-200w, switch on the resistance heaters in parallel. Nichrome takes over. As power/current increases, diodes keep the voltage down to vMP. Overall, nearly the maximum heat is extracted all day. Close to end of day, switch off nichrome heaters, let the diodes hold the voltage at vMP, until almost dark. More heat, smaller diodes, still cheap, can keep my old 50v space heaters. Nice!

[@simonmoore8414]

Ingenious. So cool that you can take out a variety of voltages from the same bank of diodes. Way more versatile than most charge controllers.

[@solarpoweredge]

@simonmoore8414 Yes... I am amazed diodes can do this :D

[@mrdervish3683]

? Is it possible 2 bypass a charge controller and charge your battery bank with manual voltage adjustments for bulk/absorb/float modes. Ie ala dirt cheap cooking where access to $&mppts r limited? Is this K.I.S.S.

[@solarpoweredge]

@mrdervish3683 Good thinking, diodes can produce different voltages. However the regulation is not fantastic. So we'd have to be very careful. Basically this is something I am looking into, and hope to present my ideas when they're in better formation. I'd love to use diodes like this, truly simple and cheap technology!

[@RRrrRRrrlandfin]

I was thinking of use led chip as a simple "mppt resistor". Benefit is that they are already installed on a heatsink and forward voltage is already high nor any extra components aren't needed

[@solarpoweredge]

@RRrrRRrrlandfin That should work, they are diodes too!

[@warrenkeillor9034]

For a heater, just put all your diodes in mineral oil instead of wasting the heeat in air. You can then be selective as to how you distribute such heat...

[@solarpoweredge]

@warrenkeillor9034 Right on :) I've done that too... most of what I do doesn't make it to video camera unfortunately

[@jumboegg5845]

He was just demonstrating the principle. Obviously the diodes aren't designed for heating, they could be much more effective if designed for that purpose.

[@ArielTipton-r9w]

How do you make a " heating" diode tho?

[@TyroniuzOz]

​@@solarpoweredge what about mineral oil with terracotta for radiative properties?.... Not sure if the mineral oil is transferrant enough for the terracotta to become radiative but maybe it would make a small oil filled ceramic style heater.... maybe...? I don't know since I'm just guessing off the limited data I see.... Great job by the way ...makes me think of how many things we could apply the same reverse amp/volt theory to.... Very awesome work 👍

[@solarpoweredge]

@TyroniuzOz Good thoughts I'm sure the oil would warm up... mineral oil is commonly used in transformers... there are oil filled radiator heaters too. What would be amazing is if we could use water, as it's the best at accepting heat. After much work I have determined the need to develop my own liquid heat transfer solution but the ingredients are extremely expensive. Currently saving up for that. If that project is successful I will share the results...

[@rclewis01]

@solarpoweredge I really like this concept, but there might be a mistake in your graph. I could be wrong, but in the morning when the sun is rising, the voltage starts at zero and moves up to the vmp (let's say 17v). Anything less than the voltage drop of the diode means that no current is flowing. That means that you are not gaining the full morning's losses in wasted heat. Once the voltage hits the vmp set by the diodes, the flat part of the chart would then start. But, nothing happens before that. The rest of the graph looks good to me. Still a definitely more efficient than a resistive load.

[@solarpoweredge]

@rclewis01 Hello and thanks for the comment! I appreciate anyone who will consider new ideas and concepts - diode chains aren't too well accepted :) Here is what I found.. the current does start out gradually... in reality, diodes have a "grey area" - much like other semiconductors where they still conduct some current. Not sure if this is leakage or what. Diode strings are not exactly like an on/off switch. The current is generally exponential, but it's hard to figure out exactly where that starts sometimes. (Especially with influence of temperature). That said, they do lose some power as they are not true MPPT... however they are simple and cheap.

[@robmc3338]

Solar panels act as current sources so the voltage rises rapidly with little solar when there is no current flowing, also real MPPT charge controllers don't work anyway is the very low light conditions anyway, so it's a loss we already get anyway.

[@jeffschroeder4805]

Using diodes as you suggest might simplify warming a 12V lithium ion battery up to the allowable minimum charging temperature (0°C) during the winter here in Minnesota. I also might also be able to tap the diodes at a point that provides a voltage compatible with a 7805 linear voltage regulator to power or signal my micro-controller. Lots of options. Thanks!

[@solarpoweredge]

@jeffschroeder4805 Lots of good ideas! Glad you liked this video. 0 degrees doesn't sound fun. Maybe a separate 100w panel to drive the diodes all the time, inside the battery case. Or inside a battery box with insulation.

[@dunckeroo1987]

The string of diodes are used as a shunt regulator, whose impedance curve can be closely matched to the solar panel curve to create maximum power transfer. *One could do the same with 3 * 5 volt TEC or thermoelectric Peltier assemblies. These are also solid state but function as small heat-pumps so can be used to build coolers or warmers (or it could keep the beer cool and coffee hot at the same time using the same devise :). The TEC's produce more heat than cooling effect. *Power diodes can also be acquired with a copper heat sink mounting tab, for higher power handling per unit.

[@solarpoweredge]

@dunckeroo1987 Been running several TECs direct from a solar panel, pretty cool technology :) I have several videos on peltier cooling if you're interested. kzbin.info/aero/PL8a6nRTNyF9PyYGFHtbVmP0tQo5ar_dfX

[@Механизм-ж9я]

Thanks for the video. I was thinking of way to boil water with minimum power. I want to have some adaptive heater for different voltages. Some FET with analogue regulator can do the job. It can be soldered to any metal plate for heat dissipation. This is a simpler heater idea with no regulator required.

[@solarpoweredge]

@Механизм-ж9я Welcome :) easy to match voltages by shorting out some of the diodes... they can also regulate themselves to the max power voltage range when connected to a solar panel (a current limited source).

[@kennedy67951]

Awesome information mate. 😊10 out of 10 from me. Thank you for sharing your experience and knowledge with me.😊

[@solarpoweredge]

@kennedy67951 Thank you very much for your kind feedback :D diodes can do some interesting stuff :)

[@StuffPeterLikes]

Nice. Full wave bridge rectifiers would be useful in some applications as they are designed to bolt to heat sinks.

[@solarpoweredge]

@StuffPeterLikes :) right on... actually using a bunch of them to heat my workshop from solar! Video on the way hopefully

[@aaronkretzmann3548]

I'm very excited by the work you are doing with this! I've been trying to figure out a distributed heater for a thermal sand battery and this just might do it!

[@solarpoweredge]

Very glad and thankful to hear it! :) I never tried a sand heat battery before. Can the diodes transfer enough heat into it? TO-220 or metal cased diodes might work better than the axial type. It's worth looking into. PS currently developing a solid state "immersion" water heating element - it could work in sand too, not sure.

[@treesareafewofmyfavoritethings]

I'm trying to figure out the same thing! I have a disused gas furnace with a heat exchanger built in that I'd like to fill with a solar sand battery but keep the electronics as simple as possible. I just looked up the max temp of diodes and it came up as 175C so I'm not sure how you'd transfer the heat into the sand quickly enough. In my case I guess maybe blow the hot air through the heat exchanger?? What else have you come up with so far?

[@treesareafewofmyfavoritethings]

​@@solarpoweredgeI just had a look at diode max temperatures and they were only around 100-175C. Is that your experience and have you burned many out? How much heat dissipation do you need? I'm super interested in what you're doing and would also like to try it in a sand battery but it seems like it might be hard to keep them that cool without something like liquid or blown air to get the heat into the sand

[@solarpoweredge]

Hmm, you are right that diodes can get too hot, I have burned out a few in these years. The fact is, the heat has to be extracted to keep the diode under failure temp. I simply don't know how to get the heat into sand, and have never tried it so can't say it would (or would not) work

[@solarpoweredge]

@treesareafewofmyfavoritethings You are right about getting the heat into the sand, which is why I have been making immersion type heaters. Have not yet shown them and people don't seem interested anyway (have you noticed all the doubts and arguing even after repeated detailed explanations lol). However I am still experimenting with free air heat exchange, you can see the experiment in the video. It does work, but I am not finding satisfactory diode packages that would tolerate such treatment at higher power levels. They don't seem to exist. Regarding the diode temp, yes they burn out in excess temperatures, so the challenge = "get the heat out of the diode before it burns". And that can be tough. Is sand enough? Well I tell you what, when things improve around here and I have time, I will put some diodes in sand and see what happens :)

[@marksaustralia6464]

Ben, this is amazing. Please make a diode hot water heater, so we can make them ourselves. All that will be needed is a thermostaic in the circuit to control the heating. This could put heat pumps out of business!!

[@solarpoweredge]

@marksaustralia6464 Hi, I am glad you liked this... I did build a HWH with a solar powered "immersion" diode element but haven't been able to present it yet. A lot of people seem to be interested in that type of system! Hope to share it soon, I am working on these projects as fast as I "humanly" can :D

[@marksaustralia6464]

@@solarpoweredge I think you need to get a working hot water system, see a patent attorney and then get seed funding. Even if it can't be patented, start a company and start selling them. The time is ripe and right.

[@solarpoweredge]

@marksaustralia6464 Appreciate the encouragement. I will make a video as soon as possible showing a diode based HWH immersion element, second version. It's a DIY project. Taking longer due to many obstacles but I'll get it done. Depending on how things go, I might look at the patent process, that would be really awesome to hold a patent.

[@mySeaPrince_]

​@@solarpoweredge Possibly.. File a copyright with a lawyer.. and ask for advice about patent.

[@solarpoweredge]

@mySeaPrince_ You are right, have been searching for a patent lawyer. Apparently "micro-entities" can file patents with reduced USPTO costs - a viewer informed me about that the other day

[@mr.makeit4037]

Great idea. I understand that the string of diodes configured in this way was for demonstrational purposes. My question is: how much heat was generated and did those plastic connecting strips melt or get really hot over time? How could a better more heat resistant strip be used to make a permanent heater? Another good job.

[@solarpoweredge]

@mr.makeit4037 Thanks :) the strips did not melt or get too hot as the fan was cooling everything well. Can think of this like any other heating element except A) diodes need cooling and B) they can regulate the solar panel voltage when solar conditions change. Therefore, they are more significantly more efficient than standard resistance heating elements when driven by solar panels. Resistance heaters don't regulate and just pull the PV voltage down when solar conditions worsen, whereas diode strings tend to let the voltage stay up near volts-max-power range. Almost like MPPT. If 100w is pushed through the diodes, that's how much heat is generated. Push 1000w, get 1000w of heat. Same as standard resistance heat. I hope to build a larger version of this heater, but right now it's summer and way too hot for building heaters.

[@mvpmachine]

Thanks for this video! I will experiment with this and see if I can incorporate it into a form to use it with my sand battery heater.

[@solarpoweredge]

@mvpmachine Great idea, planning to test a sand battery here and see how it performs

[@GWAForUTBE]

Could I glue/ solder a diode /s to a aluminum roasting pan sheet ..then bury in the sand to carry heat .

[@solarpoweredge]

@mvpmachine I am testing diodes in a small sand battery device I built. But the challenge is of course diodes burn if too hot. In cooking tests, hitting 110C is fine but sand can go much higher. Working through some alternatives at the moment, if I find anything good I'll upload and share.

[@mvpmachine]

@@solarpoweredge I ran across that issue with the ptcs and ditched them for an immersion type element I need to add a pid controller next

[@solarpoweredge]

@mvpmachine Awesome :D

[@dougbas3980]

I subscribed. Very interesting to this retired electrical engineer and HAM radio guy (N8VY). I have various solar panels for radio and running home appliances like freezer and refrigerator. I will be looking at your other videos for ideas. Thank you.

[@solarpoweredge]

@dougbas3980 I greatly appreciate your subscription, thank you :) there seems to be a lot of HAM operators on here, they must be getting into solar more and more. Anyway thanks again for subscribing and I hope the other videos are useful!

[@minitrucksofindiana2050]

I would sure love to meet you as well as design something like this for my ev's. I currently use resistance heating. They come off a dc to dc converter. But once made for my trucks I could then build numerous ones for my shop which is 2400 sq ft w/ a14ft ceiling. I have also been pondering solar heated air as well as a heating system using liquid so it would have a radiant value for x number of hours during the night. Thanks for the video.

[@solarpoweredge]

@minitrucksofindiana2050 Hi, well at least we can meet "digitally"... I'm a ways off from Indiana. Those trucks are awesome by the way. I am tinkering with small sand batteries and cheap solar-thermal setups to help heat the workshop. I prefer to use solar electric heat, but plan to have diverse heat sources. It's a great way to learn more too

[@user-vw6ej7ib5c]

Wow. I am impressed. Gor to try this. Thanks

[@solarpoweredge]

@user-vw6ej7ib5c Glad you're giving it a try! I think this idea is amazing

[@ricktaylor7346]

If you used high power bridge rectifiers in a string using only the output lugs, you could bolt them to a heatsink and transfer the heat to the air more efficiently.

[@solarpoweredge]

@ricktaylor7346 Good thinking, already did that! Took a long time to wire all the connectors... will make a video about it asap

[@ianpgeorge]

Have you ever considered a peltier based PV DC powered device ? A different semiconductor device than the diode. Wired enough of them together .. and you could get a direct PV DC to DC cooling device similar to the direct PV DC to DC heating devices .. for things like cooling the inside of a fridge or such. And for heating you might be able to get a little above a COP of 1 .. the heat taken from the 'cold' side (air or liquid) of the peltier is added to the resistive heating (from supplied electricity) on the hot side. Although the trade off would be I don't think they would do the MPPT like function you describe in this video.

[@solarpoweredge]

@ianpgeorge Yes I have been giving peltiers some thought, they are on the list to investigate further. Peltier cooling from solar panels and other applications would be really interesting. A DC converter could be used to better match the solar panel power range. I am working through some ideas and experiments, if anything good comes from it, I will record some clips for a future video!

[@trygvetveit4747]

But still very interesting part would be to make Buck Boost converters at different voltage stages..."small step boost AND Buck" Converters is far, far even by magnitude. more efficient than a 2V-48V vs a 2V-3V Boost.... You are really one to somthing here... I really need to find a way to efficient transfer power from a 12V battery bank To a 48V House system ;) And balancne at the same time... Lol, i think you just solved the problem with efficient balancing different voltages and charge, as everything. you also can use ZenerDiodes to limit Currency ? MPPT for Battery paralelling...

[@solarpoweredge]

Interesting ideas, there are many different kind of diodes. I have played a little with Zeners and they are pretty fascinating

[@trygvetveit4747]

Not so shure of zeners, they are less efficient/give more heat due to thheir swicing? i guess? Im all inn to get my Ryoby Batterys synced with my daugthers small 4kW 48Vhouse battery The perfect gift? 9Ah= 30 minutes of "free" heat if you can store energy and use it at night in a heat pump/Mini split...@@solarpoweredge

[@solarpoweredge]

@trygvetveit4747 I like the idea... batteries are fun :)

[@trevuk01]

I was just looking at a 3d printer filament dryer when I remembered watching this video. I'm thinking low heat in a air flow controlled box could possible be the cheapest way to keep them dry ?

[@solarpoweredge]

@trevuk01 Never thought of that, yes it should work - a small solar panel could power it and maybe insulate the box to improve performance

[@robmc3338]

Very interesting idea. Its so simple Im shocked I have never even heard of this idea before. Well done 👍

[@solarpoweredge]

@robmc3338 Welcome, glad you liked this! I never thought diodes could be so useful :) Currently building a simple power optimizer (regulator) for my existing solar electric space heaters. To maximize heat collection. It uses large power diodes, hope to share the project soon...

[@sbartasek]

If this is true, then my water heater setup will receive a huge boost in the next couple days! Wondered about replacing MPPT charge controllers, but have no idea how to use the heat generated from that, unless the diodes were in my preheating tank...

[@solarpoweredge]

@sbartasek The interface between the diodes and water tank is very challenging, but I recommend using power diodes with metal tabs or power rectifiers. Think of it this way... MPPT keeps the voltage of the panels up high in their efficient range. A resistance heater can't ever do that alone! But diodes do it all day for cheap :)

[@DavyOneness]

Very interesting, but unlike a resistive element they can't glow red with heat. One thought came to mind, not sure if you want to be breathing the fumes from the diode case baking in that heat all the time. A better option is you can use a transistor as the diode if you connect its legs up properly, also transistors have metal tabs for attaching to heat sinks, and pulling the heat away from the transistor package to the heat sink and then dispersed by fan off of the hea sinks. Some transistors will work better than others, and some experiments would be in order to find which ones work best. To use a bipolar junction transistor (BJT) as a diode, connect the base and collector together, leaving the emitter free.

[@solarpoweredge]

@DavyOneness Hi, valid point about fumes, I am always worried about it. Can't do much about the glowing part. But I will say they have to get really hot to make fumes. Actually this was just a bench test to demonstrate concepts, there were no problems with fumes. Especially if you use metal tabbed power diodes around 40-50C. Or bridge rectifiers which are potted (sealed). 50 amp bridge rectifiers seem to work OK I am testing those now.

[@DavyOneness]

@solarpoweredge oh yea, I forgot that some power diodes also have heat sink tabs. But I would also think transistors as diodes would be good to try, maybe try spotting something in the datasheets for the diodes that work good, and see if you can select a transistor with similar specs. Transistor also get hot with fast switching, so maybe another idea with the semiconductor heater concept is a simple blocking oscillator that will switch the transistors at megahertz speeds, maybe a simple switching regulator IC to do the trick if can't get a blocking oscillator to high enough frequency .

[@DavyOneness]

One last thought on the oscillator idea, can have one transistor do the switching to the string of diodes, I bet the switching may give you even more heat than just the straight DC through the diodes. An advantage to pulsing the voltage like this is you can almost get the open circuit voltage of the panels across the diodes, and may even work at night with full moonlight, or cloudy winter days.

[@solarpoweredge]

@DavyOneness Good ideas, everything needs to be looked into :D

[@DavyOneness]

@@solarpoweredge you got me interested in doing some experiments now when I get the chance!

[@ianball3972]

Please check out the M220.58 package type diodes, they seem to be perfect with and electrically isolated metal base for mounting on a heatsink !!! ( or finstack burried in sand )

[@solarpoweredge]

@ianball3972 Those are really outstanding, might order some to test. Thanks for the tip :)

[@ianball3972]

@@solarpoweredge I noticed you used or spec'd 20a diodes, I have been pricing the zp20a.58 on the two "Ali's" and Amazon here in Canada .. OUCH ! 20 units plus shipping is crazy price... But I can envision how nice they would be to bolt onto a heatsink side by side in opposing directions and just use jumpers. Also was picturing an old high current heathkit style rotary switch with a chicken-head knob for tapping (and in effect heat control) .. nice big terra cotta pot full of sand on a wire stand giving radiant heat for days with the load turned down to minimum once temp is reached just to keep it going. Love your work. Keep going !

[@ianball3972]

p.s they appear to be 0.75v drop on fv.

[@solarpoweredge]

@ianball3972 Thanks for encouragement, I hope to share more projects when humanly ​possible :) Great ideas! What about 50a/100a bridge rectifiers? Those can be somewhat cheap. Testing them now. I may order some of those M220 diodes if I can find a good enough price, indeed they are expensive. A rotary switch would allow instant and convenient tuning, very nice... For a sand battery project, I wanted to keep the diodes below 100C. So it's going to take experimenting to see what happens. Terra cotta pot is a great idea - I will borrow it, just need to buy some clean sand to run some test

[@solarpoweredge]

@ianball3972 Roger that, good to know

[@jasonhamilton5756]

Vacuum tubes heat up well and hold your fixed voltage like a diode does. Older tech, less expensive, longer lasting, designed to handle heating effects. I like where your mind is going with all this. The limiting factor you run into with SS electronics is that the doping is very sensitive to thermal effects. Good luck.

[@solarpoweredge]

@jasonhamilton5756 Good point about vacuum tubes. They are tough. I've been testing temperature vs. voltage on diode heaters, and it has a self-regulating effect. They key is not to let them overheat. I will cover this in the next video as soon as possible.

[@stephenbaker3680]

Wow! Neat observations. NOW..Lets hook some Peiltier finned units up to both cool a fridge, then run the heated side to heat a water heater at the same TIME. Two birds..one stone!🥶🥵=💯%use!

[@solarpoweredge]

@stephenbaker3680 Now that's good thinking :) have several peltier / seebeck experiments on the bench, hope to record them ASAP

[@sbartasek]

@@solarpoweredge if you can figure out a peltier setup that can even come close to the efficiency of a homemade compressor/refrigerant setup I'm giving you all my money and we're applying for a patent! Those things are so simple, easy, and foolproof... Just... they usually waste a lot of power

[@solarpoweredge]

@sbartasek That's what I been working on for months! Forced to pause the work, but here is a preview of later tests: I budgeted 52-55w, managed to get test fridge down to 14f in a controlled experiment. Spent months "experimenting under duress". Spent a lot of money. And then... managed to hit 14F but with only 25 watts! About 50% improvement, same conditions, same ambient. I ignored everything on yt, followed my own path. It turns out Peltiers have to be used right. They should not be dismissed. There are already companies making peltier AC units. They can get better. I have made several discoveries about peltiers, I hesitate to share them and have the work exploited for gain

[@Chupacabras222]

Very interesting idea. I see one potential problem here. PN junction doesn't like heat very much, it dramatically decreases life expectancy of such diodes. So I wonder if it is possible to manufacture diodes that could be tortured like that for years.

[@solarpoweredge]

@Chupacabras222 They can certainly be burned up if they get too hot. However a group of researchers cooked and heated water with a string of tiny diodes for months on end, and they were fine! I suspect that the low cost of diodes and performance as a heating element makes room for them in some applications, despite the risk of burning them out

[@Chupacabras222]

@@solarpoweredge Tiny diodes and tiny power dissipation could be something different as kilowatts a reliability. Any heater must be high-power and very reliable.

[@solarpoweredge]

@Chupacabras222 1-2kw through bridge rectifiers or large power diode strings is no problem at all. They can run relatively cool with proper heat extraction. Already working on that now. Around 50v MPP DC is good enough, using multiple strings of 50-100 amp power diodes and a large heat sink, possibly with a fan. All you have to do is get the heat out, which is the whole point. I am building these larger diode heaters to integrate with existing solar electric resistance heaters. Note: the diode temperature does not need to exceed 50-60C when properly built in. Edit: actually with some effort, even 40C is possible with diode heaters, if you extract the heat from the diodes - which again would be the whole point. At around 40C I don't see how reliability could ever be a problem!

[@ab22aq22]

I like the video but am having a hard time getting the point. I understand that the diode chain provides a more even voltage than resistive heaters, but why is that interesting? To me, it feels like a heater should be evaluated based on how much heat it puts out, not what voltage it maintains. For me, it would have been much more interesting if the comparison applied to the heat emitted for the different systems.

[@solarpoweredge]

@ab22aq22 Hi, this topic is apparently a bit hard to follow.. I'll try to explain it... if you still don't understand just let me know :) Think of it this way: why does an MPPT Charge Controller let the voltage of the solar panels float up past battery voltage and hold it there nearly all day? Answer: so the panels operate at their most efficient voltage, gaining more WATTS. Diode strings do a similar thing, except they're dirt cheap and simple. More WATTS = means more Watt-Hours - that's obviously more HEAT :)

[@solarpoweredge]

@Radioman. Good point! Not to mention diodes are cheap to replace. Thanks for the idea on stud mounted diodes, I'll keep an eye out for some. FYI I found some KBPC5010 silicon bridge rectifiers. They're a bit expensive but have a tough metal case with a bolt hole. Not sure they can take 50 amps. Testing them now with 5-10 amps as a regulator for existing solar resistance based heaters on the same panels. I'll post a video showing the work as soon as humanly possible.

[@TheWinstn60]

So each diode drops 0.7 volts and say its a 17 volts supply so each diode would generate 12 watts of heat. Makes sense a resistive heater will vary its resistance as it gets hotter and cooler and cant be segmented. Clever idea Does it work with diodes in parallel although that might be less efficient

[@solarpoweredge]

@TheWinstn60 Yes they will proportionally share current in parallel... Ohms doesn't work on diodes but that's exactly what makes them so attractive for solar electric heating. I used some diodes to boil an egg with a 20w solar panel... kzbin.info/www/bejne/eYPLnI2ma6p2fs0 Working on another larger diode solar cooker

[@TheDrBlackross]

cool homemade peltier junction, BUT, a tap-able large one... 0.7v per diode junction... nice thing is you can put a spiral of diodes in a tube and tap the power (take off) on the spiral at one point to run a fan at one end of the tube, that way we can see input temp vs. output temp then measure total efficiency (which would be positive either way because its solar) while heating a room or the inside of a small box area like 3ftx3ft and work out the total heat produced. pretty slick though i never thought of using diodes from a telsa coil voltage ladder this way (they're really big).

[@solarpoweredge]

@TheDrBlackross Not a bad idea... so a piece of plastic pipe, coil of matched diodes and a strong fan at one end could make a heater. For heat, we can estimate BTU/hr by converting from wattage or watt-hours

[@fookingsog]

​@@solarpoweredgeHow hot do the diodes get? Have you imaged them with a thermal or IR camera? Maybe a glass (quartz/pyrex) tube with holes drilled with a diamond bit to put the diode leads through then bend leads and solder on the outside of the tube. Diodes could be in a spiral pattern and with the leads on the outside, you could tap at any point for any voltage drop. Fan can blow through the glass tube to extract heat.

[@solarpoweredge]

@fookingsog Hello, in order to reduce the chance of failure I try to never exceed 100-110C. Technically, diodes can go much higher... I saw a research paper where they routinely exceeded 150C for months on end with no failures... but I'm not sure how long that can go on. Thanks for sharing your prototyping ideas, I take note of everything. I believe the idea of a adding the diodes to a pipe with a fan could make an effective heater while keeping the diodes from overheating. PS If you want to see some really interesting tests where they used temperature (instead of watt hours), google "hot diodes" and you will see a good research paper. They used thermal glue to fasten the diodes to a metal pot for cooking with solar. Pretty neat stuff.

[@nustar1]

I used perplexity ai to help me write this up. To manage the stresses on diodes and extend their life cycle in a heating application, consider implementing a system where smaller banks of diodes are pulsed on and off. Start with the bottom bank and work up to the top before cycling back to the bottom. This approach can help distribute thermal load and allow cooling periods between pulses. Here’s how you could manage this process with a microcontroller: Microcontroller Selection: Choose a microcontroller with enough I/O pins and PWM capabilities to control each bank of diodes. Programming: Develop a program to control the sequence and timing of diode activation. Use PWM to adjust the duty cycle, providing precise control over the on/off cycles. Temperature Monitoring: Integrate temperature sensors to monitor diode temperatures, adjusting the pulsing sequence as needed to prevent overheating. Thermal Management: Implement heat sinks or fans to help dissipate excess heat generated by the diodes. Feedback Loop: Incorporate a feedback loop in the software to dynamically adjust pulsing based on real-time temperature data, ensuring optimal performance and longevity. This method could effectively manage thermal stresses and improve the durability of your diode-based heating system!

[@solarpoweredge]

@nustar1 Wow there's a lot here, thanks for that! Btw I finally bought some bigger heat sinks, they ain't cheap. Testing some 50 amp diodes :D

[@nustar1]

@@solarpoweredge I'm excited for the results. I read the original paper & though I'm no EE it was clear to me that you did a great job putting it into a concise and easily grasped presentation. Well done.

[@solarpoweredge]

@nustar1 Many thanks for your kind feedback :) it makes all the difference. The guys who wrote that paper did an amazing job btw. Wish I had a datalogger like theirs. I am looking for something to track temperature, voltage, amps and save it. I'm sure an Arduino can do it :)

[@ArchetypalCat]

Honestly, I love AI and use it a lot - but sometimes (and I think in this instance) they can give you the answer it thinks you want to hear. That is unnecessarily complicated overkill. As long as you stay below a max continuous load of 80% ampacity and don't allow the heat to go more that 80% of the devices rated maximum heat rating (see the unit's datasheet), you can run them non stop. I have 50, 100, 250 amp diodes in power circuits I designed and built 30 years ago which run at a 50% duty cycle with start up and shut down spikes of max 78% - 82% ... and these have been in service that entire time without one diode ever blowing out. (The two exceptions were when the building they are in got hit by lightning. One hit the breaker panel and blew it off the wall. The other hit the power pole down the street, blew out a transformer in a spectacular explosion, and sent a mean spike down the line, which fried everything electronic and electrical down stream.) I say this will no intent to discourage your enthusiasm - I love microcontrollers and the amazing things you can do with them. But then again, even DIY'ers should follow basic design and engineering principles - otherwise you end up wasting time and money. A limitation mortals must endure. Since the AI's suggestion is frankly silly, here's a challenge for you in a real world power-control scenario: See if you can figure out how to turn an SCR on and off in a DC circuit using a microcontroller - a light dimmer. Then try the same thing using a Triac on a AC circuit. (Hint: using PWM is doing it the hard way :) . Depending on the power consumption, the SCR and Triac circuits in those experiments will require that the same attention be paid to duty cycle and heat dissipation. For icing ono those cakes, use PID and say a phototransistor as a sensor to double check that the light intensity is what you want it to be. (I'd say that's an intermediate level project. :) Have fun - and remember, the Datasheet is your friend.

[@phillangstrom8693]

how about using the diode string as a set power point to run a resistive load like the coils on a inferred heater so it will only start producing heat after the solar has had a chance to recharge the battery bank up to a certain voltage or at least work as an automatic low voltage shutoff but i was planning on using the diode strings similar to how you have them except I plan on inserting them into a oil space heater so they can directly dissipate there heat into the oil

[@solarpoweredge]

@phillangstrom8693 Extremely valid point. One system under testing is as follows: using an resistance infrared heater, then connect the diodes across the solar panels in parallel. The diodes will regulate the voltage to vMP. The resistance heater will consume a lot of the power, while the diode string extracts the remaining heat and regulates the voltage. Currently working on that now, and will try to document and share it when possible

[@aberdeino]

Hi, intriguing idea. As a newbie if I use a 280w 32.8v vmpp (38voc) panel and 20A diodes (0.7v drop) do I put enough in series to make voltage 0 ? Ie 46 diodes or what am I missing?

[@solarpoweredge]

@aberdeino Hi, I'm glad you're interested in these ideas. 1) 46 sounds reasonable! I'd suggest a hands-on bench test be conducted. 2) What is your operating temperature? This affects diode behavior. With about 46 diodes, there will be some hysteresis and lag time in their response. Note: Diodes drop less voltage when they are warm. Feel free to add a few extra diodes in series if they pull the voltage too low. It takes some trial and error!

[@aberdeino]

Thanks for your reply, have ordered some 20A diodes to test, really think there's something in this but being more into mechanical engineering it's all a learning curve lol.

[@solarpoweredge]

@aberdeino Welcome! This is a novel and interesting way to get heat from solar, worth looking into!

[@BrentHasty]

How hot can you make? Before they burn up? What type of diode can handle the highest heat? How hot?

[@solarpoweredge]

@BrentHasty Hello, for solar electric cooking applications, boiling point (about 212F) is quite alright for standard silicon diodes, I've seen them last a really long time in that scenario. I wouldn't go too much hotter than that though! With space heating applications, you can keep the temperature much lower... probably 50C would be fine (use a fan/heat sink etc.)

[@peterxyz3541]

Would it make sense to sit that on top of a bucket of sand to store heat for releasing the heat at night?

[@solarpoweredge]

@peterxyz3541 Yes! Working on this stuff now! Had to buy some clean sand :D

[@peterxyz3541]

@@solarpoweredge looking forward to it. I want to employ your research in this northern Ohio winter season. I just bought 4 used panels (more later after testing) at 230w each. My goals are modest, keeping a garage and tiny green house above 50. Supplement house heat, hoping to knock 10% of winter bill (hoping to knock 25% at my optimistic) After finding your channel, my ideas of the possible has expanded. Now, I’m looking at electric hot water tank. Thanks

[@solarpoweredge]

@peterxyz3541 Welcome :) I am thankful for your views, ideas and support. Those panels will definitely make heat. I just dragged out 4 more for the winter. Combine solar panel electric heaters with insulation and sealing any drafts - and it further amplifies their effect

[@canterburyworkshop5631]

Could this be applied to directly heat a sand battery? I have a home boiler system that I am trying to use a large sand battery to provide supplemental heat via solar to cut my heating costs.

[@solarpoweredge]

@canterburyworkshop5631 Hi, they can BUT the challenge is to get the heat out of the diodes into the sand. I am experimenting with that now. The problem with diodes in sand is the thermal connection. I would suggest keeping diodes around 110C for good longevity, but sand can be far hotter. Also experimenting with solar diode heated water tanks for thermal storage. I will post any update on these experiments as soon as humanly possible

[@canterburyworkshop5631]

@@solarpoweredge Excellent. I am designing the sand battery to be heated via direct solar, parabolic solar heater, and wood pizza oven in a rocket mass heater configuration. I am trying to get the sand up over 1000 F to last thru a week or so.

[@ArchetypalCat]

@@solarpoweredge see my recent post re JB Weld - I'd get a sheet of copper roofing material - the kind used for flashing. Cut a bunch of strips or squares then JB Weld the diodes to them, say onto one or two strips (in a cross or "plus" shape) each. Place them in the sand in layers. One caveat: you might want to use silicone wire - not because of the heat but because of the mild corrosiveness of the sand if it picks up any humidity. Granted it's very mild, but it is there.

[@solarpoweredge]

@canterburyworkshop5631 Wow this sounds very interesting! For my workshop, I am making a "micro furnace" with hybrid solar inputs and heat mass storage. It's experimental, at this point. The weather is getting cold so finishing the project is more pressing....

[@canterburyworkshop5631]

@@ArchetypalCat Thanks for the tips. Will keep this site informed of my progress.

[@fluffyfullbox2075]

Could you use LED's for a dual purpose?

[@solarpoweredge]

@fluffyfullbox2075 Hi, that is interesting, LEDs may not dissipate as much heat but they are diodes and will act very similar! ... worth thinking about this further :)

[@DaveEtchells]

When I saw diodes, heating and MPPT together in the thumbnail was an aha moment for me. - Or a facepalm, of _course_ ! It’s a brilliant and simple idea, you’re right, I don’t know why this isn’t explored more! I guess people generally use heat pumps for heating with solar, because they have COPs much higher than one. Still, this is a brilliant idea!

[@solarpoweredge]

@DaveEtchells Glad you took the time to investigate :) This has been a very hard concept to introduce... most people don't understand and just reject it. But diodes literally heat my workshop with direct solar electric and cook food. They are working alongside my 55v DC nichrome heaters now as regulator/heater combos.

[@DaveEtchells]

@@solarpoweredge That’s so interesting! I’m struck again by what a natural idea the diode I/V curve is for MPPT power extraction. While heat pumps have a COP > 1, cheap solar cells, avoiding electromechanical complexity and the ability to generate high output temps are all points in favor of diode heating. (Once again, the moment I saw it I thought “duh, of course!”) I wish you all success with your experiments and campaign to popularize the solution!

[@solarpoweredge]

@DaveEtchells Yeah Heat pumps are awesome. It's funny we do have 2 of them, but they don't run in winter any more, just summer. Now supplemental heat is provided by solar electric. I do like a dirt simple approach with no moving parts. Excess solar power is extremely tempting to use for heat, such as after they fill the batteries. Always wish I could have more panels. 20kw would be nice :D thanks for your support btw 👍

[@Gazr965]

The humble diode is often overlooked as a voltage dropper. Gaz UK.

[@solarpoweredge]

@Gazr965 Right on, I love the simplicity and low cost

[@bernardcharlesworth9860]

I would like to know what the loss is . Would it be induction or eddy current loss ?Also we still have an adiabatic heating system and will all know the problems there.

[@solarpoweredge]

@bernardcharlesworth9860 Hello, I believe you are referring to the losses in resistance heating elements vs semiconductor based (hope I didn't misunderstand)? Converting voltage/current from a solar panel to heat is almost always a 1:1 process, (unless it's running a heat pump with >1 COP for example) minus the losses from the solar panel not operating in its ideal voltage range. Some call this range vMP (voltage of maximum power). This is the reason for MPPT charge controllers to exist, they hunt around for the best solar panel voltage range under load, and try to hold it there. Simply put, solar panels are a variable and changing power source depending on clouds, sun, season and so forth. A static (linear) resistance heating element does not regulate itself at all, it is almost 100% linear. Therefore it is impossible to perfectly match it to the solar panels - this means power (heat) is lost. If the sun gets dimmer, the resistance element just stays the same, so the solar panel falls in voltage - losing power. An MPPT circuit would solve this problem, but at high cost and complexity. A chain of diodes, properly matched to vMP range, will hold the voltage of the panel and behave similarly to an MPPT circuit - a type of "regulator" for very low cost and low complexity. Throughout the day, the diode chain heating element has higher voltage closer to VMP on average, therefore it extracts more heat and more power. Hope this makes sense.

[@fookingsog]

Induction and eddy current (which involve a magnetic field aspect) are associated with wire-wound components. A diode is not wire-wound. It is a Solid State Device!!!

[@robduthie2979]

Try inserting the diodes into a stainless tube and seal off the ends to be used in water heating? with heat conductive paste.

[@solarpoweredge]

@robduthie2979 Good idea ty, been testing several different ways to make heating elements that are tough (and water proof)

[@mikefiatx19]

Wire in an automotive fuse then wire in a short across the tilt switch so if it engages it redirects the power from the element to across the fuse and blows the fuse cutting the power. Or, run a second string of diodes instead of using a heater tilt switch? If the heater falls over, the switch powers up the second string of diodes to kill the heat output to a safer level. The switch might weld closed but that's better than burning the house down.

[@solarpoweredge]

@mikefiatx19 These are good and creative ideas to investigate, thanks! Enough diodes switched in would essentially function as an open circuit, very interesting concept

[@jojopornebo188]

How many of the biggest diodes is needed to produce 5000 BTUs? I am ready to do this.

[@solarpoweredge]

@jojopornebo188 currently testing large power diodes to heat my shop, will upload a video about the early tests as soon as possible, it appears very successful

[@Kanuka-Forest]

Great video, very interesting. What measurement are diodes rated in and which size diode have you used?

[@solarpoweredge]

@Kanuka-Forest Thanks :) I use a mix of 6A 10A 20A silicon rectifier diodes depending on the project, very generic parts. What's nice is any ordinary diode should work, as long (as they don't get too hot and burn)

[@Kanuka-Forest]

Great, thanks for the reply

[@solarpoweredge]

@Kanuka-Forest NP :)

[@ernstlemm9379]

Very interesting. However, only to bu used to generate heat. Ever tested the setup with shotkey type diodes?

[@solarpoweredge]

@ernstlemm9379 Great thinking, schottkies are a great way to increase the number of junctions, with the lower voltage drop. I mostly use the cheap silicon rectifier diodes which drop about .5 volts or something like that. I built a larger heater recently with a metal heat sink, hope to share it as soon as humanly possible.

[@ytSuns26]

Later today I will be building that with that type of diode. I have had a couple of dozens laying around for years .

[@solarpoweredge]

@ytSuns26 Great. A 100 watt solar panel might be good fit for your test. They usually want to be around ~17 volts. Higher voltages - need a lot of diodes. The most I used so far was about 80 in series.

[@akujiwar]

Not hard to believe, but beautifully simple. direct charging of a battery with a matching voltage should also work pretty well (within safe limits! / with overvoltage protection)

[@solarpoweredge]

@akujiwar Glad you like this stuff, there are a lot of skeptics out there :D I should try charging a battery... you are right about overvoltage protection. I guess the diodes cannot regulate as well as other methods, but they are still an amazing way to create "emergency" DC power supply

[@petrovich5188]

Diode chain may replace tl431 or enother regulated stabilitron, and power transistor and lresistive load

[@solarpoweredge]

@petrovich5188 Very interesting idea... as one subscriber mentioned, a diode chain acts like some kind of regulator (except it's extremely simple)

[@Reset-hesitant]

Can you post specs on axial diodes used voltage and amp rated. I want to buy some on Amazon for testing

[@solarpoweredge]

@Reset-hesitant Hi, silicon rectifier diodes were used, (I put some links in the description)

[@SolarHarvestSolutions]

I just happened to have enough diodes for my 18 volt 50 watt module, I’m taking a wack at it 👍

[@solarpoweredge]

@SolarHarvestSolutions Great! you could add a DC fan to extract the heat. They get hot pretty quick without cooling. I am testing a large group of diodes on a metal heat sink arrangement to push more power through

[@SolarHarvestSolutions]

@@solarpoweredge they do make shotkey diode that’s flanged for a heat sink that I have quite a few of. I’m going to take a shot at …and along with a fan of coarse. Been using shotkey diodes instead of controllers in some of my matching panels to batteries were the voltages are very close (charge voltage for batteries)

[@solarpoweredge]

@SolarHarvestSolutions Great idea, those are much better than axial diodes... btw I finished building a "power optimizer" / diode heater using power bridge rectifiers mounted on a heat sink - with peltier modules on the other side (extra experiment)! It will work with a couple of PV DC space heaters to maximize watt-hours harvested as heat. I doubt it will generate much power through the Peltiers and seebeck effect, but it is worth a try. Hoping to make a video soon as possible

[@SolarHarvestSolutions]

@@solarpoweredge I’ll send you the part number for the diodes I’m referring to with heat sink flange

[@solarpoweredge]

@SolarHarvestSolutions Roger that and thanks

[@markpennella]

I noticed there was Zero fluctuation in the V, A, or Watts when you hooked up the DC fan !!!

[@solarpoweredge]

@markpennella Interesting observation - I suspect it's sharing the current. I have tried connecting very powerful fans (>10w) and the meter sometimes shows a change on the readout depending on the circumstances. It's amazing that diodes can act as a power supply.. it's not perfect but might come in handy

[@richonguzman]

great idea: is there a comercial diode heating product available or must I just DIY it? What are the diode number/name to see about it data sheet?

[@solarpoweredge]

@richonguzman Hello, I am not aware of any diode-based solar electric cookers or heaters that are commercially available. The choice of diodes is very flexible; description has links to some of the diodes I used. You can also just search amazon for "rectifier diodes" and choose ones that can handle the current (amps) you want to move. Also, keep in mind diodes need some way to expel heat, or they will burn up. Example: for a heater, use a fan or heat sink to move heat out into the air. For a cooker, take care to use a thermostat unless you are sure the diodes won't get too hot. Also, diode strings are useful only on direct solar power, they require a current limited power supply (that's what a solar panel is)

[@richonguzman]

@@solarpoweredge great info. I have a few solar panels charging my DIY 52P7S PowerWall (with recycled 18650) so I was planing to use the 28V to run all the heater with a fan for some heating air process , what do you think about it? 20A diodes are better than 10A for this process?

[@solarpoweredge]

@richonguzman I guess "Tougher" diodes should be better for heating purposes, they are harder to burn up. 20A sounds good. Working on a more powerful diode heater right now and will post an update as soon as humanly possible

[@richonguzman]

@@solarpoweredge great!!

[@tenij000]

what if try use oil and head that then can pump it around cool same time the diodios thingys

[@solarpoweredge]

@tenij000 Great idea! :)

[@jussikankinen9409]

How many diodes for heating 3x3m area and still charge battery

[@solarpoweredge]

@jussikankinen9409 Diode chain heaters aren't beneficial for attaching to a battery, only direct to DC solar panels which are a current limited source. If you're running heaters from a battery, I'd suggest standard resistance (nichrome, PTC) heaters

[@FourthWayRanch]

Can we connect solar panels direct to nichrome wire for heating sand?

[@solarpoweredge]

Yes, it should work fine!

[@FourthWayRanch]

@@solarpoweredge is there a device that will divert excess solar power to a load like nichrome wire? Prioritize running the home appliances etc? Or...just have a separate solar panel array for heating a sand battery?

[@solarpoweredge]

@embededfabrication4482 It is possible to divert excess solar power to a nichrome wire or similar heater. I used to do that with my grid tied inverters. Maybe that's a future video topic. To effectively prioritize running home appliances while diverting to heaters depending on load, would require an intelligent circuit, and I don't know where to get one at the moment.

[@solarpoweredge]

@embededfabrication4482 Saw your other comment, but it won't show up here on this page for some reason. To answer your question, diodes can last a long time if properly cooled. I read about one experiment where they used some rather small diodes for solar electric heat for 200 days straight, no problem at all. If diodes overheat, they can fail, so the key is to cool them down with a fan or immersion tank.

[@Scaliad]

​@@solarpoweredgeThe intelligent circuit is Home Assistant...

[@giannimariani9744]

What about Peltier devices in reverse?

[@solarpoweredge]

@giannimariani9744 Right on! I am experimenting with those too but it will take more time...

[@ytSuns26]

Efficiency as opposed to a heat pump?

[@solarpoweredge]

@ytSuns26 Heat pumps are relatively complex, so on another level. This tech should be compared to cheap simple direct DC resistance heaters (ex: nichrome) powered by solar panels. The diode chain has behavior very similar to an MPPT circuit. Thus extracting far more heat from the solar panels vs. simple resistance.

[@samshead]

The to220 should be a better choice as they are designed to dump excess heat through their tab to a heatsink.

[@solarpoweredge]

@samshead Right on, metal cased bridge rectifiers work too and are pretty tough

[@gicacoca5107]

Thank you very much!

[@solarpoweredge]

@gicacoca5107 Welcome!! :D 👍

[@davidrobertson5700]

How many BTU was it making ?

[@solarpoweredge]

@davidrobertson5700 Hello, it was only a small bench test, working on a large diode optimizer right now for my shop heaters, that could potentially handle over 1000w. It depends on how well the diodes are cooled (Fan, heat sink, etc.)

[@edwinlipton]

Isn't this like a voltage doubler? Can't remember things anymore.

[@solarpoweredge]

@edwinlipton Hi, I don't know all the proper terms, I guess it depends on how the diodes are used: if we connect some kind of load across a few of the diodes while they're active, it could be a "voltage potential divider". In fact this could be used as a rudimentary emergency power supply with very basic regulation. For example I was able to get 5v from the heater while it was running - pretty neat for such a basic circuit

[@smithpianoservicing3421]

Magnificent

[@solarpoweredge]

@smithpianoservicing3421 Glad you like this :D :)

[@mikejones-vd3fg]

very cool

[@solarpoweredge]

@mikejones-vd3fg :)

[@miken7629]

Wouldn't a string of SCRs do the same thing, with tabs easier to mount on heat sinks

[@solarpoweredge]

@miken7629 That's something to look into, also there are power rectifier diodes that can mount to heat sinks (they have metal plates)

[@ArchetypalCat]

yes but that's a waste of the SCRs (or Triacs too) function --- you'd be basically dumbing down the SCR (or Triac) and turning them into diodes. :))) Just get the diodes - they'll be cheaper anyway - and your SCR's will thank you for not insulting them. :P Many diodes come in that same tab package as well as the power diodes @solarpoweredge mentions that he uses to heat a work space. The 'stud mount' TO-3 package is perfect for this application, IMO.

[@pauldunn1164]

Brilliant

[@solarpoweredge]

@pauldunn1164 Hi glad you like this... maybe some company will build us a diode solar electric heater or cooker... I'd certainly buy one!

[@Buongona]

so, u are running a diode heater with another diode... clever

[@solarpoweredge]

@Buongona Hot diodes are a bit obscure, but I am using the idea to heat my workshop :D

[@HubbHubbs]

So it holds a roughly constant voltage all day like mppt, but have u done a side by side comparison with a normal heating element to see if it is actually giving a much higher output? As dunking diodes in water isnt ideal long term, but well worth experimenting with.

[@solarpoweredge]

@HubbHubbs Normal heating elements were already the basis of comparison.. if a normal solar powered resistance heating element was pushing 50-100w all day, but a diode string on the exact same panels and conditions do 60-120w. Easy calculation! Boiling diodes one of my earlier experiments kzbin.info/www/bejne/pKaXZaqId6qlmZo

[@7sonderling]

brilliant! but i subscribed because of the orange tomcat ;)

[@solarpoweredge]

@7sonderling George thanks you for subscribing :D He is a real piece of work.... some of my older videos have cat pics. I love my cats, they will make more appearances in the future :)

[@adamrak7560]

power of the exponential voltage-current relation!

[@solarpoweredge]

@adamrak7560 Right on!

[@solaroweder3707]

Love your channel! Brilliant idea! When i began experimenting with PV I used a "MPPT" tracker that actually didn't track. It just tried to keep a preset voltage. I considered it useless and bought an actual MPPT tracker. But as the years go by, I, too notice, that even good MPPT trackers don't do much more than keeping a constant voltage. Yes, in low light conditions it tends to be 15 V while in bright light it tends to be 18 V. But really...is that worth all the electronics? You are also saying: As long as you run any PV to load circuit and you put in one of these diode heaters you can then also run other consumers in parallel at a constant voltage in almost MPP. Lastly: I appreciate your efforts to express as precisely as possible by adding comments to correct yourself.

[@solaroweder3707]

Actually I'm not sure it's possible to run anything in parallel to such a diode string.

[@solaroweder3707]

Ah, right now you bring up the DC power supply. So yes, it does work. I'm amazed by the simplicity.

[@solarpoweredge]

@solaroweder3707 Thank you for the kind feedback :) for some reason it has been very hard to get the concept of diode strings established with the public, but you have absolutely grasped the idea. Yes that's is exactly what I was working towards - diode strings in parallel with my other PV-DC heaters. They act like a pseudo regulator, holding the solar array quite close to MPP/vMP range and are dirt simple and very cheap. This way complex electronics can be altogether avoided, and we extract more heat from the solar panels while still using robust and cheap resistance heaters of all kinds.

[@solarpoweredge]

@solaroweder3707 No worries, it can work - I have tested it already :)

[@solarpoweredge]

@solaroweder3707 I think it's amazing too... diodes don't regulate perfectly, but I don't mind, the benefits far outweigh minor voltage fluctuations

[@trygvetveit4747]

I could balance my 18V Ryobi Battery against my 48V Hose bank? (80-100kWh) If so!!!!!!!! (Or my salvaged 12V lead ) Makes me wonder....

[@solarpoweredge]

I happen to love Ryobi, so I am for anything 18 volts :)

[@isaiahhesslup8463]

Blessing

[@solarpoweredge]

@isaiahhesslup8463 Hello and bless you :)

[@debscamera2572]

Why not use direct solar heat, no electricity, no solar panel? Like a solar water heater

[@solarpoweredge]

@debscamera2572 Flexibility... solar thermal has it's place! but it cannot run air conditioners in summer, cook food indoors, charge batteries or much else. Solar electric heat is slowly appearing more and more in the residential space, it just takes time. As long as solar panels remain cheap, it will become more common.

[@alhumble8175]

Can you show us how you connected the diodes to each other, and did you mount themcall on something? I couldn't see this on your video. Thanks

[@solarpoweredge]

@alhumble8175 Hello, the first video shows hooking them up: kzbin.info/www/bejne/bHWTkoijoLqEibM A diode string is simply diodes connected in series. There is no need to mount them on anything as long as the fan moves enough air. If diodes get too hot, they would burn out. Sometimes heat sinking is required, it depends on the type of application and how much wattage is dissipated - Hope that helps . -DD

[@alhumble8175]

Thanks very much. I watched your referenced video and it too was very helpful. Keep the good video instructions coming. The time is right for your important experimentation!

[@solarpoweredge]

@alhumble8175 Welcome :) I agree, this kind of tech really needs more investigation!

[@fookingsog]

Simply mounted in a nylon terminal block--in series and tapped off at various mid points to obtain various required voltages.

[@colinhamer6506]

I'm a new sub to your channel I'm going back through you video's to get up to speed 👍. I brought up something that doesn't make sense to me why it's not being used all ready on a domestic solar channel and only got sarcastic comments back Edison etc. The main point behind it was there is a lot of things around a house that are actually running on DC most well under 24v all with there own AC-DC converters each wasting energy converting AC to DC TVs router's charger's light bulb's etc does it not make sense to have a DC loop in the home if you have solar DC to AC and back to DC doesn't make sense to me and even if you don't have solar 1 efficient converter possibly combined with a battery to get rid of all the questionable power supply's we are being sold

[@solarpoweredge]

@colinhamer6506 Thanks for subscribing! I understand exactly what you're referring to, and have experienced the same environment on YT. You know what they say, can lead a horse to water but can't make him drink... DC is certainly the way to go. For example I am building out a low voltage DC home datacenter among other projects. It makes perfect sense to have LVDC available in the home for running small appliances. I want to skip the inverter whenever possible. Also am building out a low voltage solar-powerwall and many small appliances that can run straight off the solar with battery optional. Here's one of many examples of efforts to move in that direction: kzbin.info/www/bejne/sHa9YZ6baZ2Ura8 Again thanks for subscribing, and hope you enjoy the videos! -Dave

[@pareidoliarocks]

Wow

[@solarpoweredge]

@pareidoliarocks :D :) 👍

[@ferencszabo3504]

Interesting stuff, I gonna look into it for sure! Maybe it's not developed because it's not a commercially "viable" product! If it doesn't break you have to buy it just once😊! It's too effective!

[@solarpoweredge]

Right on!!! :)

[@greengooflight]

this can explain why a computer feels like it heats like a small heater with a lot less watts used

[@solarpoweredge]

@greengooflight Just a general FYI about the video: solar panels produce more power at an odd voltage (the maximum power point) and the diodes can sort of regulate to that voltage, they make more heat and power. A normal heating element is linear and cannot regulate at all without assistance. That's why the diodes end up being more efficient overall

[@user-px2sn8pr5t]

Can you do it can you do this yourself

[@solarpoweredge]

@user-px2sn8pr5t Yes DIY'ers can do this, I will try to release some instructional videos about this as soon as humanly possible

[@Johnnyclean]

@@solarpoweredgeI’m holding you to your promise! Haha. Is there anything I can do to help you get that instructional video out for your subscribers? Thank you.

[@solarpoweredge]

@Johnnyclean Haha... well I'm the most tied down person on earth and yet clinging to productivity... lol. Thank you for offering help... you might only have to wait a few more days... the series of "diode videos" has taken a huge amount of time. I am about to release the next video where I heat my workshop with diodes, plus hybrid them with Nichrome. There is "some" instructional material in the upcoming video. I actually wonder who will watch such material, guess we'll see. Of course the work has already progressed onward, I am building a semiconductor solar electric space heater. It's endless... but if you still have questions after this next video, just let me know :)

[@cgmarch2359]

From what I can see 10a diodes are cheaper .For example 10A2 from DC COMPONENTS

[@solarpoweredge]

@cgmarch2359 Yeah, and the 6a are pretty cheap too. I am testing some 10a diodes, got 50 of them.

[@cgmarch2359]

6a might be to low. 10a with 8amps continous..

[@cgmarch2359]

Btw ..for cooling ..maybe find some alluminium pipe that fits them and you drill some holes and put the diodes in series ? If you find a smaller diametter pipe.. cut 1 line on the length so that they fit in tigth

[@solarpoweredge]

@cgmarch2359 Very interesting idea, maybe put some heat sink compound as well. Releasing a vlog soon showing the solar cooker project, I used liquid for a heat sink

[@cgmarch2359]

One thing that might be interesting to figure is using the diodes in series to heat sand or salt for a thermal battery. Can allu/copper pipes help ( considering also maintaince)

[@wojciechbedzinski9551]

I developed my own solution to power water well pump directly from DC solar (no battery nor utility). Simply it measures amount of current available from PV array. To make it safe there is voltage stabilizer implemented in software that mimics zener diode behaviour, but at 350v level. In practice you program voltage, and any excess voltage (power) is dumped into heater. That way motor I better has stable voltage 350v DC, and is connected thru SSR if DC current exceeds programmed current level (say 4A) Captions are in EN, sorry about quality, I used translator kzbin.info/www/bejne/iWTYfGCed5ermacsi=eJlzuzHzRbpaQFHN

[@solarpoweredge]

@wojciechbedzinski9551 I like the setup, great job!!

[@robert65755]

I like the idea of this. But I would guess that diodes haven't been used as heating elements because they give off toxic fumes when they are max overheated. And could possibly burn or catch fire.

[@solarpoweredge]

@robert65755 Hi, I do too - Hope to make a couple more projects soon. 1) For direct solar electric cooking I protect the diodes thermally - very important! thermostat etc. 2) Max 110C they are quite safe. Others have tested them this way for over 6 months with no problems. If a diode ever failed, 10 cents to replace. 3) For space heating, the diodes can stay well below 100c with proper cooling setup. No need to reach cooking temps, just heating the air.

[@solarpoweredge]

@robert65755 You might like this. A 20 watt solar panel boils an egg with diodes! kzbin.info/www/bejne/eYPLnI2ma6p2fs0

[@trygvetveit4747]

First of all Love your videos!!! But if we talk efficiency those pesky lavs of thermodynamics come into play...(Hate them) A resistor is pr defenition 100% effective... If you put your Diodes and my recisitive wire into two diffferent thermo flask i bet we both will win or be tied..(A solar panel will produce the same amount of energy if you do a short cucit , even at....Zero Volts, it will still heat up the leading wires and internal panelsnwires until somting "cooks" and desolder/burn off. Maybe and im think you are rigth in some sense You can make a really more efficient Battery charger .But not shure if it can do this unregulated? Regulated at different Voltage maybe? Btw: at really cold summer mornings ,just before sunrise my solar panels give 240V on each strings..but just 6W... At 12AM i get 8kW from each string.. You need to check average given energy...as in your "paper" curve and do the same regarding a resisitive heater.. And you also got a really interesting point using Diodes like this because you can work loads at higer Voltages and skip the cost of enourmus sized copper cables....I really do! Btw, I use solar/Battery to run my house heating by tading electrical energy int a Heat Pump At 0C i give it 2kW and i get approx.5kW heat Regards from really cold Norway

[@solarpoweredge]

@unionse7en good explanation :) the diodes are almost static as shown in the beginning of the video, so all you have to do is roughly match enough diodes to vMP and it pretty much can hold that voltage. There is some variation but not like a resistance element

[@solarpoweredge]

@trygvetveit4747 Thanks I'm glad you like them, thanks for watching :) actually the diodes will win the efficiency contest, and I've literally tested this on the bench. And already checked everything you mentioned (resistance curve vs non ohmic diode string). [By the way, it's been researched in university too, I'm not the only one.] This is where theory and actual hands-on application and research are important. I assure you diodes produce more heat with a solar panel - period. You have to think through this carefully or do actual testing. Solar panels change throughout the day, resistance element is linear and hardly changes. As the sun rises in the morning on the solar panels, the bare resistive element will seem like a dead short to the solar panel, so little to no heat and very low voltage. The diodes on the other hand, will already be warm and operating at a much higher voltage, already producing heat near vMP as they don't act like a dead short. As midday approaches, no doubt a properly matched resistance element will at some point climb up into the vMP region for a short time and match the diodes. But it cannot stay there, the voltage will keep rising linearly and leave vMP region quite soon. Wasting yet more power. Meanwhile, nearly the entire time the diodes were almost fully loading the solar panel by holding the voltage at or near vMP - near constantly - as the current (amperage) rises. The resistance element won't have a chance to keep up, and it will only match the peak power output of the diode elements for a short while, then fall back behind again. At the end of the day, the diode string will have produced significantly more watt-hours (or heat) than the resistance element, but from the exact same solar panel. Game over :)

[@trygvetveit4747]

May actualy heard of this..But still Maxwell states 100% effifiecy ... Think the argument for better efficiecy had to do with ambiant temperatue and the same efficiecy as your diodes can do as Balance different Voltages extreemly efficient compared to use swiching electronics For f..Sake, i think you just solved a lot of major efficiency problems for home battery banks... @@solarpoweredge

[@solarpoweredge]

@trygvetveit4747 well independent of any equations we can see that a solar panel is most efficient when operating at volts-max-power range, and diode strings can hold it there almost all day as a function of their properties; while resistance elements are simply unable to do so and are governed by almost strictly linear behavior. This is like comparing PWM charge controllers to MPPT. Why do MPPT charge controllers exist? They are more efficient at extracting electrical power from the solar panel - same as the diodes. What do MPPT charge controllers do? Hold the solar panel in the vMP region nearly all day - conveniently a simple diode string behaves almost the same. The result? MPPT charge controllers extract more watt hours. And diode strings - they do just the same, using a different method. They both increase efficiency of solar power extraction - using different methods. The MPPT charge controller puts the watt-hours into a battery, the diodes put the watt-hours into the medium as heat or could even say as BTU/hr.

[@zusclhz]

This is a wildly obscure discovery with just diodes !! 🤯🙏🚂🎼🌹🎶🎵⚕️~C< 3)>>-Z->}

[@solarpoweredge]

@zusclhz It's a really unusual technique!!! Amazing use of cheap and simple technology... also, I am heating my workshop with solar panels and 50a power rectifiers. Works amazingly well... video as soon as possible... You might like to see an egg being cooked with diodes and 14w of solar power :D :) kzbin.info/www/bejne/eYPLnI2ma6p2fs0

[@zusclhz]

@@solarpoweredge 14w cookin an egg! Thats what up !! Infinite Tech in Infinite Thanks! Good Vibes for Your Creation!!! 🛠⚕️🎵🎶

[@solarpoweredge]

@zusclhz Glad you liked that, thanks for the support :D :) 👍

[@jimhibbard1546]

They are acting like a regulator.

[@solarpoweredge]

@jimhibbard1546 Yeah seems to be the case. There were several other tests, the string of diodes held the solar panel "roughly" at volts-max-power (vMP) most of the day without intelligent circuitry. When solar conditions change, the voltage does fluctuate, but not as much as a resistance element. The result is more watt-hours through the circuit and thus extracting more heat versus a bare resistance element. The resistance element just followed a linear behavior as solar conditions changed, pulling the solar panel out of vMP range, thus missing out on a lot of power throughout the day.

[@hellhound-si5oz]

You stud diodes into heat sinks that would be a better way to get the heat out of them

[@solarpoweredge]

Thanks will look at those, also found some square metal rectifier diodes

[@xavieraxiak6866]

Audio!

[@solarpoweredge]

Yeah using 2 microphones kind of failed...

[@ManyHeavens42]

Thanks Im a Doer! 🩴🩴😭🤣😂😅

[@solarpoweredge]

@ManyHeavens42 :D :)