DC2DC - Buck, Boost, Buck-Boost & SEPIC - 12v Solar Shed

Along with solar charge controllers my collection of DC to DC converters grows almost weekly. These handy little modules allow me to power devices at different voltages to my lead acid battery bank.
Items used in this video:
❗️These links are affiliated and I may earn a small commission if you purchase❗️
5A SEPIC Converter: goo.gl/9CpWjh
Minghe D3806 Buck Boost Converter: goo.gl/j15I9c
LM2596 Buck Converter: goo.gl/IntNli
150w Boost Converter: goo.gl/UKlKIH
DC-DC Buck Converter with LCD: goo.gl/D5fOHU
In this video I go through how some of them operate and test a new addition to the collection.
Wikipedia links:
Buck Converter - admw.uk/iT
Boost Converter - admw.uk/iR
Buck-Boost Converter - admw.uk/iS
SEPIC - admw.uk/iQ
#Buck #Boost #SEPIC #DC2DC

[@TheShivbabber]

Just want to say thanks for the time and effort of the video, it cleared some things up for me. I just purchased a Drok DC-DC converter, but im happy with only 3A. Its to mess around with a fire works ignition system. I'm going to try to power it via a 2A USB power bank! Cheers again for the info!

[@AdamWelchUK]

+Trick Style You're very welcome. Glad to be of assistance. Thanks for your comment.

[@schubi128]

Thanks for leading me to the PM-6009. I was looking for a up/down converter for a mobile 4s4p Lithium pack that allows me to power 12V appliances when fully charged as well when the voltage drops. Although I found some of those Its nice to have one which I also can use for other Voltages without the need of having a screwdriver and multimeter with me. I never found the PM-6009 on my own.

[@WildLifeBackyardCamera]

as a non native english speaker and after having watched so many of your videos, so many times... i can fully say that i'm able to watch and understand your nice english accent without having to turn on the subtitles ;). Jokes apart, all of your videos are really instructives and well made !! Thanks a ton for the time and effort

[@AdamWelchUK]

I’m glad they’ve been of use to you. Thanks for taking the time to make a comment. I really appreciate it.

[@shaneweightman]

Many thanks Adam ,, good videos and thanks for your time and replys Shane

[@bucketlistbeginner]

Great video could you take the time to show a server or multiple server smps using a converter to make it a bench supply

[@pulesjet]

Looking for a BUCK/BOOST that can operate between 10 - 60V @ around 20A. Thought I had one good to 60v but it turned out to be Boost only.

[@PBWillyWonka]

Great video!!

[@johnf3326]

I am trying to find a converter that will take between 3 and 17v on my motorbike and output 14.5v to charge the battery and power lights. Basically its a 6v to 12v conversion. Current draw could be quite large for small periods so the unit should not burn out. It should be capable of supplying maybe 5A or even more. I find the more powerful units will only take a minimum 8v input. Hard to find a catch all buck booster to do all this. An excellent review by the way

[@pulesjet]

There has to be a way to Boot Strap added FETs and Inductors to these Buck Boost converters allowing for higher amperage. Using one of the little 5A MPPT's to operate at say 20-30A ?

[@exxonrcg]

I bought one of these converters and they are very useful and quite affordable. Only problem is my stranded wires for DC in and out keep coming off the screwed terminals. How do you do it for yours? Do you tin the ends? or use non-stranded wire?

[@milvolts1]

Great vids Adam, hey I need some advice and I hope you can share some with me. I have made a 4s7p pack to power my waterfall and lights. I have a 10amp pwm charge controller. My solar panel is 40watts and my pump is 12v, 21watts -1.7amps. My led light are bout 12v 11watts and 1.4amps. Which buck converter do you recommend? Also do you think a BMS for my pack is necessary? Thanks, have a nice day.

[@daveparf]

Thanks for explaining these converters, there are so many to choose from on eBay lol, Would you be able to recommend one for me please? I have 12 generator coils each producing 35v and 1 amp but I lose the voltage when I Measure the amperage, so I’m hoping to set a buck converter to 12v and as many milliamperes as I can then connect all 12 converter out puts together, but can’t decide on a buck converter.

[@tbbw]

Would be kinda interesting to see the effichensy with let's say a 5-10watt load on these :)

[@drteeth7054]

Great video. It is the second of yours I have seen and have subscribed.

[@AdamWelchUK]

Glad it was of use, thanks for your subscription!

[@davidfrancis2139]

Would it be able to convert a small panels 2volt to 12volt for battery charging?

[@monaxp606]

I have a question...Can I put two or more buck converters in parallel ? My solar panels providing 20v/10amp approx.. I just want to put two or three buck converters between panels and charge controller(pwm) to provide 14v/13amp to charge controller. If I use only one...it heated very quickly... Thanks in advance.

[@andywatts4774]

A very interesting channel, just subscribed.. How efficient are these converters compared with, say, an LM317?. Do they generate much heat , especially when the output is a lot lower than the input? Many thanks

[@krishnakumarphy1]

Great Video, Solar panel open-circuit Voltage: 40V Battery 12 V (AGM Controller : PWM controller max input voltage 28V I need to step down from 40V to 25V and connect to solar charge controller to charge the battery? Will I lose energy in this converter in step down mode? Or the module will convert in to Amps from Voltage while step down? Which boost buck module I can buy? or it is not at all possible with converter? Thanks, krishnakumar

[@kavasrahul8877]

Can you please upload me the breadboard connection for this dc2dc converter

[@wiegehtsdenn1234]

I have a 12V/100Ah solar battery. How do I connect my 19.5V / 7.7A = 150Watt laptop? (Can i use any boost converter that can handle 150Watt / 12V = 12.5A? Some boost conerters mention a max Amp input. How is that related to the 100Ah of the battery?)

[@brucewoods9377]

I heard someone said try red insulation tape across the LED readout improves the view ability on camera

[@shaneweightman]

Hi Adam ,, sorry to be a pain that converter sepic, do you think it would work to charge my ebike battery off a car battery from 12 volts to 29.1 volt at 2 amps ,, as at the min I'm about to set up a solar powered charging system ,, not good with electronics but learning cheers Shane uk. Ct1017

[@stationlunda3020]

What is the quiescent power? These converters may use too much energy themselves for use in a Off-Grid solar project!

[@DavidBeede]

Hey Adam, great video. Really clearly presented. I'm trying to use a solar panel that is 300w 42v 7.4 amp for two purposes. One to charge a 48v Lithium e trike, and also charge a 36v battery bank on a pontoon boat. One requires boost and one buck so it seemed the boost buck SEPIC device might be perfect but I can't seem to find any in that volt / amp range. Any ideas? Thanks again for sharing your expertise.

[@AdamWelchUK]

That’s quite difficult. Julian Ilett hopes to make something that does this, but the design is pretty much a concept at the moment. Sadly I think you are looking at two charge controllers which stay with the two battery systems. Cheers.

[@Magic-Smoke]

I was excited to find the video on the SEPIC module. Unfortunately its no longer available. Maybe its time for a video on controlling the others with Arduino? :)

[@gravelydon7072]

john macrae, They still are available. www.ebay.com/itm/PM-6009M-Programmable-Buck-Boost-Step-Up-Down-SEPIC-DC2DC-Converter-Power-Supply/282971428736?hash=item41e2695780:g:TZsAAOSw1m5a~usk

[@tupai62]

which module is suitable to charge 6v 7ah SLA battry?

[@dragan3290]

Hi ! Are these worth repairing as i have a 600watt booster and a 1200 watt booster! Parts are hard to find unless its overseas! Any reply appreciated thanks from Australia!

[@WildlyIntrepid]

Thanks for the very detailed video. I have a question about using some of the buck boost chips. I got one of the fancy ones for 15$ on Amazon with the LCD. I set the voltage and as I was setting the current up from 0 as soon as it changed it smoked and is toast. I'm wondering if I was using it for the wrong purpose or if maybe it was just a faulty unit. I was trying to charge my a lifepo4 battery with a lead acid battery. Everything was hooked up correctly so I'm thinking it was just the unit but I'm wondering if maybe it can't charge a higher voltage battery. Both batteries were 12 v but of course the lifepo4 has a higher voltage than the lead acid. Cheers.

[@PortugueseUN]

could you potentially use a buck/boost/sepic in place of a solar charge controller for lithium ion batteries?

[@maxneyasit8130]

Для этого есть преобразователи с возможностью CC/CV режима.

[@miteshdhanani]

As shown how can we connect it with 3w 6v solar panel and adjust

[@DocMicha]

Very nice video. As old electronics nerd, i have one question: If I would build a power bank, or some similar device, several cells in parallel would not need to have a balancing circuit. If I then take a boost converter I can adjust the voltage eg. to 5V, which I want. Higher than the 3.7V of a LION Battery. On the other hand for e.g. 5V output I could use 2 pcs. 3.7 Volts in series an take a buck converter, but then I need a balancer for charging. So for the lower hardware effort, I would choose the 1st option with 3.7 V and boost converter. What is now better, and why not use always the cheaper 1st Option. Could you tell this?

[@AdamWelchUK]

+DocM As you say, running cells in parallel and boosting the voltage to 5v is the easiest (and exactly how most usb Power banks work). If you use two cells in series technically you’ll need a balancing circuit which may burn off some of the charge current and you’ll still have losses in the buck conversion. I’d go with the boost converter personally.

[@DocMicha]

Thank You!

[@rossco4002]

hi Adam can I use one of those to power some leds lights with a USB 5v out and 12v in to the lights to come on when you turn the computer on thanks

[@AdamWelchUK]

+Ross Musolino you could boost the 5v to 12v to power your lights yes but with a few caveats. The current on the 12 v side will be much lower - you need to do some calculations. How much does your 12v led lamp draw? For example your PC might be ok with 1 amp at 5 volts (5w). That would be about 0.4amps at 12 volt before DC-DC losses.

[@badkeene]

Sorry for asking , Is it possible to hook up a (100Wp) solar panel to a Dc2Dc step down converter ? Yes I know there are charge controllers but those require a Battery.

[@AdamWelchUK]

+steven keene Yes it is but you'll have to manage your load carefully. Try to pull too much power and the voltage on the panel will crash and your load will switch off. DC2DC converters don't care about managing their input.

[@pets4489]

Why is the d3806 the highest output module I can find on the market. I just want a stronger dc/dc buck boost!

[@kavasrahul8877]

It's amazing video can i get breadboard setup potentiometer setup

[@jkbhatt72]

sir we required 24 volt DC 40 amp suggest the best converter

[@giacomomarszal258]

Qualcuno lo sa se uno di questi si può usare come un alimentatore fisso applicando un trasformatore 220 V per un trapano 18 v / 2 .0 AH ( DEVALT)

[@kami37781]

Must watch again. Still unsure how Buck converter or boost converter works. Combined both, what r the advantages

[@motormadness9975]

Boost converter outputs only above your input voltage, buck does above and below, but only smaller current. A buck/boost can seamlessly transition from outputting above or below your input voltage. (which is why they are so handy)

[@AdamWelchUK]

+Motor Madness Not quite. Check out the Wikipedia links. Boost lifts the voltage, Buck reduces the voltage, Buck/boost can do either - as can sepic.

[@offgridamps]

Hi, love the videos 👍 Im using a d3805 buck boost to charge Li-ion pack about 17ah I want to double up my current is it possible to run two of these buck boost in parallel to get double Current into the battery? Or would they conflict and pop

[@ifell3]

Great video, i have brought to boost buck converters, one uses the two LM chips and the other is a LTC3780 chip, which has supposed to be more efficient, and can buck down to one volt, could you shed any more info which is a better chip set? Regards

[@AdamWelchUK]

Using two ICs means two processes are being completed - usually boost then buck. Both stages will have losses so one chip is most likely to be more efficient. The LTC3780 is really clever and is a single synchronous rectifier (I think). It uses four mosfets in a complicated algorithm and can be pretty efficient. I got one myself (after I made this video) but I've not done a video on it - mainly because Julian Ilett did an excellent one here... kzbin.info/www/bejne/qGGueYOuoautbKs

[@ifell3]

Adam Welch great explanation, cheers.

[@james10739]

Hey I was wondering if anyone had tried using a buck converter in between a solar panel and a pwm charge controller and set it up to like 14.4 or whatever then you still have the protection but more power I know you could not do it with a lot of power but a 100w might be doable

[@kavasrahul8877]

How much have to pay for this full set

[@uthayak]

To get 12V portable supply from Lithium Ion cells ( 18650) , instead of building a 3S 3P pack with protection boards and active balancing board , is it better to build 1S 9P pack and use boost converters? other than conversion loss is there any other drawbacks ?

[@lostshadow7161]

It drawing high inputs from bank so it's has to do more problem is heat of the A of the battery

[@carlostorrez260]

Adam, I am looking for a constant 12v buck/boost with at least 4-5amps anything cheap you would recommend for me please!

[@The_Last_Post]

Hi Adam, I need your help understanding what's going on with the small Sepic I have (as shown in your video). I have a parallel bank of 5, 12v 2amp gel batteries which is being charged by an old 12v 0.5ah trickle charger (transformer type I think). I noticed the output of the charger was way too high, 15-16volts! and could hear slight sizzling going on, so I put the Sepic shown in your video in line to drop it down to 13.8v. Now the odd part, when the batteries are being charged one at a time with the Sepic, my volt meter shows 13.8 across the terminals. All cool. I tried this with 5 batteries in parallel and I can see for a second the Sepic tries to raise the voltage from whatever state it was in (say 12.45v) but it won't go up to the 13.8v?? It will stay at 12.45v and won't budge. What's going on here? Why won't they take a charge? I have tested all the batteries internal resistance and they are low. Hope you can help!

[@AdamWelchUK]

+TheLastPost I'm guessing that with all the batteries in parallel the small amount of current flowing into the batteries is struggling to raise the voltage of the pack. Half the size of the bank and see if it raises slightly under charge. If it does you'll need more current going in to properly charge the bank.

[@The_Last_Post]

+Adam Welch thanks for replying. But yet more oddities, I have a total of 16x 12v 2amp batteries so I tried a different pair in parallel. They are taking the 13.8v charge fine! However, I have tried halving the original bank and they won't charge at 13.8v. They stay at their original state of charge of 12.45v.. From what you say, do you think it's the 0.5ah charger that's struggling, even though some pairs seem to be ok with it and some don't?

[@AdamWelchUK]

+TheLastPost Have you tested the batteries individually? You might have a faulty one?

[@The_Last_Post]

+Adam Welch yes all 16 take the 13.8v fine individually, and their internal resistance is all around 2-4ohms so theoretically should all be good to go. It just seems very odd when I can put a pair together that they will charge when another pair won't, or indeed a set of four or more won't budge at all..

[@The_Last_Post]

+TheLastPost would it be worth taking off the Sepic and letting the charger put out 15-16volts? Or turn up the Sepics output to something higher? Obviously the amp will be the same low 0.5ah

[@lindaphillips8303]

On the red triple trim ports every time I put a multi meter on it it shuts down are they any good for charging 12to24 volts battery banks

[@radius.indrawan]

Linda Phillips is it possible that your multimeter was set on Amp reading instead of Volt, thus basically it short circuit the module and it went shut down?

[@mnelson10000]

That's pretty cool, but was the voltage spiking like your meter showed? For example, at 13:20, you touch the pot and it jumps from 7v to all over the place and then settles back down to 8v.

[@AdamWelchUK]

Yeah I trust my meter is reading correctly. I'd put this down to a poor quality pot, breadboard connections and fat fingers. There's nothing averaging the analog in of the arduino, so any anomaly on the ADC reading would send the voltage off on the SEPIC. I'm confident if I wired this up correctly, and added some averageing we'd not see that spike. Thanks for the question.

[@mnelson10000]

That's kinda what I figured, but Jim Conner had a video about weird spikes with some of those generic buck/boost modules and ever since then, I've been kinda punchy about it haha

[@AdamWelchUK]

mnelson10000 Well you've put enough doubt into my mind - I will check that. Thanks

[@arrowstheorem1881]

When i adjusted the constant current trim pot, nothing happens. Only the voltage trim pot is working. Any suggestions sir?

[@AdamWelchUK]

Put a filament lamp on the output. That will allow you to see a difference in the current in the brightness of the lamp.

[@arrowstheorem1881]

Yes i did sir. No change in intensity of light or orange glow. I was using lead acid battery 7ah. I just tried using lithium cells 4S. The brushless motor seems to throttle more like normal.

[@sanelemiya7792]

hi Adam m designing a sepic converter can i know which chip is preferable? and the mosfet that is used?

[@AdamWelchUK]

+Sanele Miya I don't build them - I just buy them! I'm not sure I'm qualified to answer.

[@sanelemiya7792]

ok thanks can you read the one's that are used in the one's you buy

[@MrMworlds]

Nice informative video but it seems that PM-6009M Programmable Buck-Boost Step Up Down SEPIC DC2DC Converter Power Supplyis no longer availableThank you for info

[@AdamWelchUK]

Oh really - that's a shame. Thanks for your comment.

[@inspectormore-anonymous1259]

type in programmable buck boost on ebay, there are much nicer ones available with separate lcd screen for around 30$

[@binaryglitch64]

Uh yes it is... As Rafiki (from The Lion King) once said... "look haaarder".

[@DavidBeede]

The exact same one it appears is available from Aliexpress. tinyurl.com/ycsybcq9

[@binaryglitch64]

See, told ya.

[@vylbird8014]

I don't know if this is any use to you, but I put this thing together recently: gateway.ipfs.io/ipfs/QmeCqXxspQN8Fa1dZ7W94nucyXA28qUcGbzc3c712PRHDa/ It's a battery discharge protection circuit for lead-acids: Cuts the power to a device when an adjustable low voltage is reached, then turns the device back on when the voltage rises up to an adjustable high to indicate battery-full. You can buy them easily enough, but this design is super-cheap, has a very low component count, and is easily adjustable. I use it for garden lights so they'll turn off before lowering the battery voltage too far, along with a dark-switch based around a photoresistor and 741. I have one of those SEPIC converters too. It is a really nice board. SEPICs do have a fundamental drawback though, they can't supply a great deal of current. If you look at the schematic for one you'll see why this is the case: Getting high power through a series capacitor is not easy.

[@AdamWelchUK]

Thanks for showing me your load controller - a neat design. Yes sepics have that draw back sadly. Buck-Boost for higher currents.

[@jec_ecart]

I've never heard the word sepic with respect to dc converters before...

[@johnconrad5487]

90% of the so called reviewers on You Tube dont understand even the basic concept of power supplies... you turn it on and apply input voltage and show how good the device is, without any mention of how you have loaded it. thats the same with you. it is a power supply intended to supply POWER i.e. Voltage x current... not zero current... with zero load what are you demonstrating?

[@gazzacroy]

spot on..

[@ElektroLUDIKITS]

Book converter ? 😄

[@AdamWelchUK]

That’s what we say oop norf in the UK :-)

[@MrBrymstond]

I'm not trying to ruin your day, but these onboard Chinese led readouts are never accurate and then you test it with your best volt meter and that has a different reading so now what? You rush around the house to find a Samsung phone charger and you find a different reading, but it seems more accurate to the ratings on the charger, but you go to check the amperage and you get zero's well that's because you have to short it to find the amperage and higher quality chargers have a protection circuit and cheap one's don't! So you can sync your imax b6! How do you know your volt meter is dead on accurate? Did you sync it to a oscilloscope? You can do it by taking the back off and adjust the screw while it's connected to a professional oscilloscope if you have one or take it to a shop then sometimes you can get one of these cheap power supplies that you can sync and some you have to remember the real voltage readings and set it up that way. I had so many of these that over charged my 18650 cells to 4.4v and some 4.0v so this will help

[@AdamWelchUK]

+MrBrymstond I've checked my meters against an AD584 voltage reference. I would like to find something similar (and cheap) to check current too. There's a video on my channel about the AD584 if you're interested.

[@MrBrymstond]

There's a way to adjust a number of these devices, the imax b6 you hold the DEC and the Start button while plugging it in and it will initiate the ability to adjust your settings but you're going to need a professionally accurate machine to match it to. I took my volt meter to a shop with a high end oscilloscope and matched it so when I use these boards I know I have to stop them at +0.2 or -0.3 and mark them. Some of these devices that have the same kind of buttons can be adjusted the same as the imax like that very buck boost in your picture here top right corner, it's digital and I watch someone fix the issue.

[@lezbriddon]

omg..... you dont need .001v accuracy on everything, and as for the b6 flash a decent firmware

[@shaneweightman]

Hi Adam ,, sorry to be a pain that converter sepic, do you think it would work to charge my ebike battery off a car battery from 12 volts to 29.1 volt at 2 amps ,, as at the min I'm about to set up a solar powered charging system ,, not good with electronics but learning cheers Shane uk. Ct1017

[@AdamWelchUK]

That sepic converter doesn't seem to be available any more. To be honest you don't need a sepic converter, just a boost converter. Something like this should do it but at 29.1v that's fairly close to it's limit: goo.gl/TvXI5v You can find others with voltage readouts and the like, but this is the simplest type.