Parallel Inverters - Double the Power Hack! Part1

[@edwinv83]

NO!!!! I've been loking for days how to do this on youtube and there are no videos, TRUST ME. THIS IS THE ONLUINE I FOUND! GOOD JOB SIR!

[@mikedesverknopf4681]

This is fascinating. I'm trying to run loads off a solar panel without a battery so I'm researching everything with the array to see where I can bypass it. I really appreciate your thoroughness and clarity of speech. Compassion for the people who make the products we use every day is important too because no one ever thinks about them. It's nice to see a channel less focused on its own success while still delivering the same amount of care, effort and humility you'd find in one that's paid for and fake. You're an awesome dude and you're really helping me out right now. Can't thank you enough for posting this.

[@knurlgnar24]

Glad you found this useful. On another note I would encourage you to look into other methods of using a solar panel to power non grid tie loads when not connected to a battery. Solar panels really need a battery or energy storage device in order to directly power any useful load. I would recommend looking into a charge controller set to 13.6V and connected to a small 4 cell LiFePO4 battery powering your inverter. The battery can be quite small but it needs to be there. The charge controller and 4 LiFePO4 cells adds some cost to your setup but it will operate as you intend and last a long time. Charge controllers can be had quite cheaply and if you purchase cells on aliexpress or the like you can find a 20ah LiFePO4 setup for a pretty reasonable price. This type of setup will only run when the sun is shining but will be able to continue running for short times when a cloud passes, a bird flies over, a leaf lands on your panel before blowing off, etc.

[@mikedesverknopf4681]

What about a bucking device to a charge controller and park in the middle of an open clearing? No issues with that on a clear sunny day right?

[@mikedesverknopf4681]

I simply can't afford any kind battery bank both at cost and space and weight right now. Free, sure. But nothing in life is free. It would cost me the same in batteries as it would for a complete solar array.

[@sequoiabentley4643]

You could possibly make a battery out of salt water for pretty cheap

[@Mattlawton-ft6ew]

​@@knurlgnar24where you beefed the solder up you could of put copper for better power 😁👍

[@samuelbaldwin3408]

I liked your video. It was very informative and I really appreciate the fact that you took the time to go over in detail the construction of the circuit board and gave a brief description of the functionality of the components in layman's terms so most people are able to understand and comprehend. So with that being said, thank you. Keep up the good work.

[@303nitzubishi4]

Everyone bashing the theory and saying it won't work are either skipping parts of the video or don't understand what he is saying when he is detailing the components and layout of the board. Anyone with basic electronic knowledge will understand that the theory here is solid and I'd bet it will work for this specific board design.

[@originalnightshade4582]

It works this isn't the only video that proves it!

[@javiercoronel1169]

Oldest video

[@marioluna4344]

I wonder if you can do the same thing to a portable power station. For example the first power stations that came out were the Bluetti EB240. Great power station lots of battery power but very small sized inverters (1000 watts) for the size of battery power.

[@garycrumrine9538]

I agree wit William. Buy 1 bigger inverter instead of mucking around with connecting two.

[@ghostunix731]

I recommend a ups invertor and solar panel. Sure it might be expensive to have solar ups but hospital bills might be expensive but burning down. Your home is expensive to

[@Coolkeys2009]

I promised I wouldn't rant but I have 4 bits of broken IT equipment and 3 were more or less faulty out the box. Whenever you pay good hard earned money for a product and receive a poorly made piece of cr*p. You have a contract between the retailer responsible for selling you the cr*p and the manufacturer that produced the crap. Those are the only people that should be blamed the retailer for selling stuff they new wasn't fit for purpose and the manufacture for not maintaining quality control or hiring/keeping good/skilled staff, giving proper staff training, motivating staff etc. If a business puts profits ahead of customer satisfaction you as a consumer should not be happy. With all the corporate advertising/news media etc. We often forget that we have a right to get what we paid for and often love/respect business's we should actually be angry with. Anyway good video, glad to see you back.

[@virtualbox9556]

So quick question, if you just plug a male connector into each outlet and then have the negative and positive output from both inverters meet up with the use of some diodes or rectifier to allow both 410W to be combined into one female outlet?

[@danwells7691]

Coolkeys2009 how would you get satisfaction. from the chinese

[@markregan6133]

This is one of those hacks that gives hacks a great reputation. I thank you. BUT please add a caption warning about never making a double ended mains lead for any purpose they are lethal especially in Europe with 220v to 240V.

[@ghengiscrayon]

OMG. The wave forms! I am a few mins in and I am fearful for the result.

[@RiaRadioFMHD773]

In Japan the AC mains is 100VAC (60Hz South Japan, 50Hz North). I use 115VDC much. Any high speed switching power supply should accept DC as it goes through a bridge rectifier anyway. Of course this will not go through any transformer, but I do use my laptop & curly fluorescent lights on it. Any resistive load like soldering irons or incandescent lamps will not see any difference. NOTE: being off grid rules.

[@dashtesla6431]

That's a good thing, the best off grid system would be DC/AC hybrid, i would go for 20x12V batteries 240VDC (arcs level photonicinduction) and an industrial 240VDC inverter so it runs induction motors etc, if you're running your own custom system doesn't matter where you are you can use any voltage you want ac dc 120 240 etc

[@freedom8480]

" full bridge rectifier" rulez 🤣🤣 Okay, different channel.

[@DobleWhiteAndStanley]

Damn your hands are HUGE! It made that battery look absolutely miniscule.

[@jeremiahputnam3893]

I like the idea. They should have pairing ports like the new inverter generators do. Then you could buy smaller ones and link them up later over time and money.

[@daniellange4772]

Stacking inverters is easy with most wholehome inverters, you usually link em with a cable to sync the waveform.

[@knurlgnar24]

It's been a while since I released an inverter video and it's past time I do so again. This is a project I worked on about 6 months ago.

[@danyala.1659]

Now I just hope this will work with 5 inverters!

[@danyala.1659]

Actually, I cant do this with 5 inverters... they will fry each other up.

[@danyala.1659]

Can you use this instead? www.smarthome.com/a-neutronics-mlsl-11510-10-outlet-19-rack-mount-power-strip.html

[@knurlgnar24]

Danyal Ahmad Looks like it would just connect them each together with a switch to turn each one on and off. They'd still go 'poof' when switched on if not synchronized!

[@ash2870]

knurlgnar24 Sir can we make a pure sine wave inverter at home? Is it possible or too complicated?

[@80amnesia]

thumbs up for trying a daring experiment

[@bjornahh87]

I was wondering what if you put some highvoltage capasitors to the outlet too so you have a bigger reservoir to get power from, did that to mine 600w 12v inverter and soldered an ac capacitor over the socket in the back of where you plug the cord in, and now I can use a 500w 230v oven on the inverter when it gets wery cold outside, and if I'm roadtripping I'ts so nice with some extra heat too...

[@wwsummers]

i recommend just using a larger invertor. use the smaller ones for portable power or something else.

[@noonrideevening1804]

or you may use head and you don't have to buy. And if bigger power need is short-term, its trowing money away.

[@jacknifedbl]

reminds me of your vid a year or so ago when u tied 2 UPS units together...great vids btw!!!

[@colinsmith6340]

J1 is the current shunt. Look at the other side of the board, a jumper is not needed there. Its also high in the air too. J1 is your current shunt.

[@goofykl9]

I was looking for this, now I have a way to build a frankenverter

[@jameswilsin5348]

Use a 3 way cord two male ends and one female ends conect your power switches to one switch then they kick on at same time but use two of the same brand and or same size you do it same way thst you would do 2 60kw generaters and have a breaker in one side the cable turn both on let tge one stableize the make sure the breaker is of turn on other inverter let it power up then flip breaker it will eather work or it will blow tge breaker

[@Doubleolseven]

I hoped you would connect one control signal to both inverters in order to have both output bridges working in synch. Each inverter would still output nominal so they would need to parallel the outputs somehow. Like they do with gasoline inverter-generators.

[@ghengiscrayon]

Ok, so by parallel stacking at the bridge before the high voltage dc hits the output Fets, you avoid a catastrophic failure via non synch waves (don't cross the streams Egon) BUT if the output section performed cool, why not just stack the Fets 'n' caps in the input section and push the Output section to the max in one, smaller box?

[@abyssunderground]

Presumably the transformer wouldn't cope? And I doubt the existing traces would be good enough for double the current either. They'd probably need some modifications.

[@davidhopkins9021]

U could buy a 1000w inverter just a thought

[@TheSign2020]

If you don't mind explaining where do you wanted to plug the inverters and why would you need it? And where are they usually used?

[@tonycooper1909]

So can u just add an external capacitor to any inverter to add to wattage like a 5k capacitor wired to the capacitor of inverter?

[@carlosreyes6448]

How would you connect them, in series for 240v

[@PatricksDIY]

12:31 That is a voltage limiter, if the size of that copper is increased it allows more power to go through since it lowers the resistance, but could also burn up the board and render the unit useless with all the extra voltage. I have seen people by pass (bridge) that

[@DavidTomko4u]

does it matter which one you plug the socket in if you want to plug one higher watts appliance

[@rileyham9058]

This is very informative and makes me curious if you could run them in series to get 220v power because i cannot find a 220v inverter(i understand a vehicles electrical would have issues but i would be upgrading mine)

[@knurlgnar24]

This could be done if a person synchronized the inverters and also connected them to separate batteries. (they reference battery ground) From a practical perspective it is always better to simply purchase a larger inverter. This was a fun experiment however!

[@00708046]

I can't make out the alligator connections . Are you just making a parallel connection from the + leads and the - leads ?

[@tonygernstl3859]

What was the whole actual purpose of soldering the 2 individual wires to both inverters? I want to attempt to parallel connect 3 cheap chinese inverters together and want to know If I have to do exactly what you did.

[@poseypapusdiazfamily4630]

To add more surge power just add high voltage capacitor in parallel with high voltage dc one.

[@josepeixoto3384]

Very good idea,thank you.

[@Max-kn9yi]

I would like to combine 2 jupiter 2000 watt inverters from harbor freight. Not sure I can do all this, but they are on sale now

[@kokopelli314]

I use braided copper solder wick to beef up connections.

[@lancelot1953]

Hi Knurlgnar24, great videos, very informative and well documented. The only thing I would recommend is to warn viewers BEFORE you demonstrate the wrong way of doing something or how "not-to-do" some procedure. The reason being that sadly enough, some less inquisitive viewers or viewers that are "in a hurry" do not listen to the entire video and blindly follow your initial procedure. You are right though, some people will connect both of them as you showed in the beginning. Ciao, L

[@FieryPotKitchen]

yery true. ...that wrong way could have been eliminated

[@MrIsuko]

Thank you so much .You saved me so much time ,I was thinking of this idea for long time ,thank you.

[@johnrobertelardo9787]

Rookie question: Can I connect the inverters in series to, say, I have four piece 12v inverter connected into series to create 48v input?

[@knurlgnar24]

Unfortunately no, you would need a 48v inverter. They will not 'share' the voltage evenly.

[@RogueOntheRoad]

As a beef it up bus point instead of just adding a bunch of solder also solder a piece of large wire to the trace. The copper wire increases conductivity as you said solder alone doesn't much. Use stranded wire for even better conductivity.

[@manolisgledsodakis873]

Use the braided copper screen from a good-quality coaxial cable.

[@court2379]

How is stranded any better than solid? You either have the cross section area or you don't.

[@RogueOntheRoad]

Actually what I was thinking was to use the solder wicking braided copper. Once it is soaked with solder it doesn't matter if it is stranded or solid the standard wire should support the overall strength of the conductor path.

[@kellycarver2500]

I bought a Schumacher 2000 and was wondering how many solar panels and batteries I should get to use with it. I plan on sometimes running some power equipment, but usually just lights, a mini fridge, and maybe an inline water heater off and on. Any input would help. Thanx!

[@mwilliamshs]

"you end up with a pile of smoke" love it! if you were shopping for a 1500w pure sine inverter to use daily for 3 years, what's the least you'd expect to spend?

[@DMAN22yeah]

samlex go power or thor they are all the same thing and they are good quality

[@KillaBitz]

i've had expensive inverters pop in under a month and right now i'm rocking the cheapest one on ebay (the first one died but i got a replacement and the fan circuit didn't work on that so a just wired to 12v) I had 7 inverters last year. This one has been going every time the sun shines for 9 months but i cant recommend it. Inverter recommendation is difficult especially when you put in a time requirement. do you live in a warm climate or a humid climate or both? are you trying to power inductive loads? are you expecting to pull 1500w from it all day (running at %100 will stress it) are you going to power it from clean power even? (it's no good trying to pull so much power from 1 small battery it drops to 9v if the inverter isnt designed to run that kind of current) You haven't given any information at all

[@MATTE.U.K]

This is probably a really dumb question but why not just connect the negative and positive together on the input and connect to the battery? What is being achieved by soldering them together by the capacitor?

[@knurlgnar24]

The output AC waveforms are not sync'd nor balanced so they can't be connected together directly.

[@jameswilsin5348]

I find cold solder joints in all mine i just redo them and they are good

[@mangreat71]

My Question is do it has a built in fuse like a 5 amp or a 10 amp or even a 15 amp ? Cause what i was trying to do is make a home made jump starter or power pack for charging appliances but i think i need a fuse like a 10-20 amp car fuse with the top post car battery ???And which 1 of these inverters has a built in fuse like a 5-20 amp fuse ???

[@BalkanFamYT]

What about putting the two power switches of the inverters in parallel? Curious how the two waveforms would overlay on an oscilloscope

[@knurlgnar24]

That would be the better way to do this but it requires more work. You would need to remove the FET drive from one inverter and parallel the FET gates between the two. You would also need to ensure both boost circuits boost to nearly exactly the same voltage. I actually planned to do this but decided it wasn't worth it.

[@josepeixoto3384]

@@knurlgnar24 Thanks for clearing this up; i have 2 inverters, same exact model, cheap from China,5000 / 2250 W , 24 volts, and i would like to parallel them to get ~~4000 watts; i repair PCs,laptops TVs etc (but NOT at component level, i´m not that good); Do you think it can be done? parallel the FET gates, with a cable between them, and check the 220 V outputs? if the FET gates are in parallel,you think the 2 sinewaves will coincide all the time,no drift? Thanks

[@jeremyhenderson163]

Thanks for sharing,great ( thorough ) video. An chance you could tell me why my (new,out of box) inverter "fault" light displays and anything plugged in comes on and then off (continuously,until unplugged). I thought maybe they weren't getting enough current from my batteries,but that seemed too obvious and didn't want to short they.

[@EngDrewman]

Is it possible to convert an old generator to an inverter generator by running it's output through a bridge rectifier and connecting it to the output stage of the inverter as shown here, maybe with a small 12v transformer to power the inverter circuitry?

[@FourSeasonsHD]

Because you have the knowledge, can you perhaps answer this question - when I test mains socket fed by power company, only one of the two holes is energized (Line). But when I connect inverter to the same house grid and power from inverter, now both holes of the socket are energized (Line and Neutral both illuminate tester). What is the basic difference here?

[@gravelydon7072]

That is true on some units but not others. In a house where you have 120 and 240, the house is using a split phase. The transformer is supplying the 120 from a center tap to either Line in. That center tap is also grounded at some point in the wiring. So line to line = 240 VAC while Line 1 to Neutral or Ground or Line 2 to Neutral or Ground will only show 120VAC. Neutral to Ground should show nothing as they are connected. In the inverters, they can be wired one of two ways. Line can be at either 120 VAC or 60 VAC. In the first case, Neutral would show 120 volts to ground as it is the second leg of the 120 VAC supply. In the second case, the Neutral to Ground would also show 60VAC as the Ground is tied to the center point of the 120VAC supply. In the second case, do not ever tie the ground to a house circuit as it will blow the inverter. If you had a second inverter of the first type and had it synced to the other unit so that one side was high on the Line while the other unit's Line went low and tied the Neutrals together you'd see 240VAC on the two Lines and nothing on the Neutral to Ground with 120VAC from either Line to Neutral or Ground.

[@FourSeasonsHD]

Thanks a lot for the reply. I had started to figure it out based on similar idea that while the volts are up on the Line they would be down on the Neutral and this would produce 240V in-between. However, it looks rather complicated and certainly requires digesting especially how the in house ground behaves together with the inverter so that ground will never become energized. Here where I live the ground is often tied to Neutral line in older homes (now prohibited but standard practice several decades ago).

[@gravelydon7072]

It actually still is in use with the Ground and Neutral tied together normally at the first panel that the power goes to. Our home was built in 1978. It has the tie ins at the transfer switches and in the main panel. Power from our generators is 240/120 with 4 wires for Line 1, Line 2, Neutral, Ground. All of our sockets also are tied to ground thru both the conduit and or the ground wire that goes to each one.

[@badactor3440]

Will this work with higher wattage inverters?

[@STEVEisAWAKE]

Very well done! Thank you for sharing some of your knowledge. Much appreciated...

[@mickgatz214]

4/5ths thru your video. Interesting! i myself am dabbling with inverters as such. Keep up the good work. Cheers Mick

[@skipwilson5086]

Mick, what have you done to your inverter? I'm trying to increase the Amps out of mine.

[@dominicsanthuff]

So to get more watts outta a inverter I wanna upgrade I just gotta upgrade the capacitors and maybe the output

[@shooyooyoon9007]

so soldering two inputs and two outputs ?

[@jonandkariwalter2074]

Can you just split the load on the ac outputs by paralleling the supply wiring to the load ?

[@knurlgnar24]

If the outputs are perfectly in phase then yes. This could be accomplished by removing the FET drive from one unit and paralleling the 2nd units drive to the others FETs. If you try this without internal modifications they'll fight eachother and blow fuses, or smoke depending..

[@markrobinson3884]

Is there a way to turn a 220 volts inverter into a splits 110 / 110 inverter

[@eDoc2020]

@@markrobinson3884 The easiest way to get split phase out of a 240v inverter is to hook up an autotransformer on the output. Commercially available 120/240 step-up or 240/120 step-down transformers should work provided you install the required connectors.

[@REVIEW_JUJUR]

Can u parallel two different UPS into a big power inverter???

[@MrAamir136]

OokTiaopi. I want the same answer

[@YodaWhat]

@OokTiaopi @ aamir habib -- Probably NOT. There are tons of different ways to make inverters, so they are likely to be too different inside, running the "150 volt" DC bus at different voltages, or employing radically different approaches to the system design. But you CAN add larger capacitors to either inverter, and likely get some improvement.

[@bartw5908]

Great video, well done, I have a Spark 4000w pure sine wave, not used a lot, but the last time I used it the wattage meter ramps up and it goes into overload and shuts down with no load plugged into it? Do you have a video off what this could be?

[@knurlgnar24]

I'd recommend ohming out the diodes and output FETs. Sounds like a shorted FET on the output stage. If so that can usually be fixed by replacing just the FET or FET pair that shorted. You don't need to replace all of them. The tricky part is figuring out what to purchase to replace it with. Try to match up the capacitances in the datasheet and be sure the resistance is similar and the voltage rating is at least as high.

[@sofabike]

How to get 2 invertors in serial connection, in order to get 2 fase and 240V ? I want to power Aluminum MIG welder what works out of 240V 2fase. Power welder takes is about 600watts. Or welding current DC +30amps and +20volts I do have 2000wats inverter.

[@DMAN22yeah]

+sofabike just weld with car batteries

[@YodaWhat]

You can get a 120-to-240 volt transformer or autotransformer to step up 120 to 240 volts, but putting 2 inverters of 120 volts each _in series_ will give you *2 different AC frequencies at once.* That is NOT the Split Phase power you asked for, unless you can synchronize them, which is not easy. And welders may have odd waveforms on the input current, which will not work so well with inverters unless they are way oversized in watt ratings. *_IF_* you absolutely have to do it via inverters, I recommend getting a high wattage inverter or UPS, like 3000 watts. At that power, they often have 240 volt outputs already. But they will probably require at least 24 volts DC as input, and may require 36, 48, 60, 72, or even more volts. Already at 24 or 36 volts from car batteries, one may do pretty serious DC welding, but that is probably not your MIG welding.

[@voglerlake]

what about taking an extension cord mail plug in double up on that Korea have to mail plugs not looping back to each inverter but is supplying the main load line of the extension cord?

[@biatchhh2334]

do you have a video that shows how to hook the inverter into your home circuit panel?

[@knurlgnar24]

kzbin.info/www/bejne/r5rco5xmgMdsjdk The approach shown in the above video is simple and low cost, but is for emergency purposes only and I go over the many dangers of this approach.

[@robertallen80]

in your opinion who makes the best for the money pure sine wave inverter in the 6000 watt range ?

[@dashtesla6431]

If you really need 3kw+ you should think of a higher voltage system and possibly a dc/ac hybrid 120vdc or 240vdc far more efficient and you don't need any inverters, everything else can run on smaller inverters far more efficient on the cheap side probably 24v or 48v should do but it's still 100-200A so.. i really don't like wiring things over 50A personally i think if it's taking more than 50A you really need higher voltage cable losses are too high costs too much etc

[@jamest.5001]

Dash Tesla yes I agree. always go with the highest voltage you can. they are more efficient with higher voltage. along with less amperage. so cheaper cost in wire.

[@gravelydon7072]

50 Amps is not high current. Wait till you have to deal in hundreds of amps at thousands of volts or thousands of amps at hundreds of volts.

[@retrodigi375]

Will current distributed betwwen them? Or will they each take the same current as if it were a lone convertor, i desire to pull a lot of amps but a single convertor just isnt rated for the full desired current

[@realflow100]

Ooooooookay that sounds like it would work perfectly..... I noticed they can both be used seperately as in 410W to each one seperately.. OR 820W in only one or the other. That sounds like a very interesting idea and the idea sounds like it would actually work.

[@johnconrad5487]

I know this is an old video. did you finally find the current sense 'resistor'? it is there in front of you. Perhaps now that 4 years have passed you either found it or figured it out. Also why did they rectify the output of the transformer and then add another stage? is this a real sinewave inverter or is it a modified square wave inverter?

[@jacovandeventer1939]

You dear Sir are a genius, i was wondering, is there a way to share the output through both sets of output FETs

[@knurlgnar24]

You have to tie together both the output of the boost stage like I did here, and also the gate control circuitry for the bridges. (disabling one of the controls so that they don't interfere) I was afraid connecting them with long wires would lead to problems so I did not do that.

[@jacovandeventer1939]

@@knurlgnar24 Awesome, thanks for the reply. I'm from South Africa where our power stations have been neglected to the point where we can't generate enough electricity to supply the entire country so they have implemented "load shedding" were they periodically turn of electricity to towns across the country and for some reason it is cheaper to buy 2 or 3 smaller inverters than 1 high wattage inverter but im afraid that the FET's on say 2 x 1KW inverter won't handle the possible 2KW current draw hence my question about connecting the FET's

[@TonyLing]

I think that crude link with high temperature sleeving on the input may be a current shunt

[@allinthefamiliy3122]

Hi Knurlgnar, i have enjoyed your videos about inverter reviews. You have a good voice, good explanation and good tests. I have a question, based on your experience what Ebay inverter with a good price performance ration do advice me to buy. Thanks.

[@angrytiger9346]

Could you use the same process that you did with these 400 watt inverters for your samlex 3000 watt inverter if you had 2 or would it be a little different if so how I would like to at some point do it for a cabin or house

[@knurlgnar24]

Timothy Moulton I actually do have two 3000W samlex inverters and I've considered just such an arrangement. Unfortunately they're expensive and I don't want to blow them up. :( Pure sine inverters are much more difficult to parallel since the FETs switch at high frequencies to generate the sine waves. The idea I had was to power two different phases of a distribution transformer with them, and then use the other side of the Xformer to get your power at the proper voltage. You would then only need to sync the two and ensure they both shut down and start up at exactly the same time rather than mess with everything else. Still, it's too much of a kludge for me for an inverter that is already very nice out of the box.

[@meowsoftware7258]

Can I use two 4000w inverter parallel ?, is that risky ?, one inverter capacity is 4000w continuous and 8000w peak, so I have 8000w continuous and 16000w peak

[@chevytruckman34]

Mad solder skills!!

[@larryreagan6936]

Just asking a question, would it be better to use a step up/down transformer using each 110v leg as input and step down the 220v from both inverters back to 110v on the transformer output at the higher rate? again "just asking"

[@gravelydon7072]

How are you going to sync the two? The output of the inverters has to be synced to work on a X1/X2 and Y1/Y2 input of a transformer to get 110 VAC out at double the current on the output side of the transformer. If they are out of sync, you could see anywhere from 0 to 240 VAC on the output until the inverters tripped.

[@ohsofficer]

Please show a test result for the output, also, one inv has 20a fuses and the other 25a, should be the same

[@martynohara8101]

I have 2 x 3400w inverter generators that do not have parallel facility. Could this hack work to provide parallel facility to my generators. I have technician friends that I would get to do the modification if this is possible. Thanks for your advice in advance

[@joecox9958]

No, your power stage MOSFET won't have enough tolerance to double output. You need sync both output stage, if you can rewire the inverter control chip has sync inputs or use single control chip to drive both output stages, you could have two outputs phase sync so you can parallel the outputs.

[@martynohara8101]

@@joecox9958 Thanks for your advice Joe. Do you know where I can get some advice on syncing the output so I can a technician friend to fix it for me

[@garyburkhart4150]

Are these inverters pure or modified? Can I assume that with the initial inverter whine that they're modified?

[@knurlgnar24]

These are modified sine inverters.

[@garyburkhart4150]

Awesome, that's what I have. Ordered them under the presumption they were pure because that's how they were advertised. Glad to know I can stack them and use anyway. Thanks

[@garyburkhart4150]

So can I ask some advice? I remodeled houses for ,32 years but my experience with electrical and electrical circuits and what not is very limited. I've built a small scale power plant (so if I blow anything up, it won't be a "costly" mistake) I've wired my batteries in series, parallel, series parallel and can barely light a digital bulb drawing only about 7 watts. I mean, barely comes on. Everything is reading proper voltage with my multimeter. I'm lost. I have 4 lead acid batteries and all are reading 13.7 volts. My inverter is reading 25.6 v DC in, 118v AC out. I figure it's either my charge controller or the inverter. Leaning towards the inverter

[@joepah51]

Excellent video.. well spoken.

[@douglaswindsor120]

To get more capacity through that solder on the board you should have added a piece of copper wire and imbedded it in the solder

[@tomyhadera91]

at first I was like what did this guy smoke and then he smart . thanks

[@robertpolito6139]

You can add 10 AWG copper wire to the bus bars by solding on the bus bars.

[@johnathanadalia9367]

Hi can I ask if this process would work on a xantrex prowatt sw2000watt inverter?Thanks for the videos by the way, They have been a huge help

[@knurlgnar24]

This was mostly me messing around with inverters because I wanted to rather than anything practical. Those inverters are much higher power and are SW making such a hack more difficult. It could be done but I wouldn't recommend it.

[@wannamikeout]

@@knurlgnar24 I have two identical xantrex prosine 1000w 12v, it seems like the same board is used for all of the other wattage models. Do you think using the guts of one to populate all of the unpopulated spots on the PCB would give me a higher output? Assuming I modify the current shunt? By the way , your videos are awesome and I look forward to when I notice a new one pops up. Your a smart dude

[@sephangelo4603]

This is good because I have yet to see one inverter for sale capable of handing like 30 batteries.

[@live4491]

I don't know if you still check this video, but question for you.... you linked the two capacitors together. Could you instead install a bigger capacitor in it's stead (same mf reading; double the voltage) to achieve the same thing? Curious...

[@knurlgnar24]

I was paralleling the boost stages where the limiting factor was the FETs. Adding capacitance would have had little effect. The output stage was highly stressed the way I did it because only one inverter was using its output stage, but given most of the cost is in the boost stage they had skimped on that and I didn't need to beef up the output stage.

[@Thomas-ZET]

Can you use one plug from each inverter to get 220?

[@knurlgnar24]

They would have to be locked in phase, so without more modifications no.

[@brandonedwards7166]

Every inverter I have owned over the past 20 years has had external fuses. How is it uncommon?

[@gravelydon7072]

Look inside most of them made by Reliable or many of the modified square wave units. The fuses are internal and in some cases, even soldered in place.

[@jamesedwards1528]

Could you point me in the direction of a 3000 good name pure sine wave inverter yeah

[@knurlgnar24]

I'd recommend this one linked here, I also added it to the video description. It costs a bit more but is a true honest 3kw inverter that will power anything a 20A outlet in your house will power, and that's more than most 5kw inverters can do. It's also quiet, reliable, and efficient. amzn.to/2JQKmbr

[@kevin9c1]

You could have added a short wire on that node you added solder to, assuming it would fit back in the case.

[@josepeixoto3384]

of course...

[@johnbrown-uv6kn]

would a apc es750 ups accepet power from a modified sine inverter ?

[@jameswilsin5348]

Or just use a 3 waycable and a breaker between tge 2 and start primary tgen start secondary flip breaker try that dont need to take them apart or you can do the smart way andjust by a larger inverter

[@xanataph]

Do they use one ov the tracks as a super low value current measuring series resistor?

[@knurlgnar24]

That is very possible and a common cost saving strategy in inverters, though the tolerance of such 'resistors' is so poor that it is mostly ineffective. In this particular inverter I don't believe they use this method.

[@eDoc2020]

@@knurlgnar24 I know this is a bit late, but I believe the wire on the bottom is being used as a current shunt. If you look it's connecting two adjacent tracks on the board (if it wasn't a shunt they could just use a cheaper track instead) and there appears to be a small sense line coming off of one end.

[@asifiqbal4590]

Hi I am big fan of your work...need some help to make parallel inverter....

[@kevindewinter8235]

Interesting. This vid is quite old. Any update or other vid with update in 2024

[@knurlgnar24]

I haven't been making many videos the last few years and probably won't make another like this one. It was just an experiment for fun.

[@mewantbrains]

You could clip out the last 20 sec of this and air it as a commercial and sell your modified inverters Also will this work on inverters of different sizes I have a 600W inverter and 2X 1500W inverters all pure sine wave will I be able to connect all 3 of them together to get 3600W using this method?

[@gravelydon7072]

Only if one or both of the 2 1500 watt units or the 600 watt unit had Mosfets that could handle the 3600 watts. That is what most people missed in the video. His units had Mosfets that were capable of handling double the power that the inverters were marketed at. So he simply supplied them with double the amps and let them do their thing under the control of one unit.

[@Iainm]

@@gravelydon7072 hopefully he's done his homework and they are rated for continuous running at the higher wattage.

[@SteveWrightNZ]

Parallel the AC output of those units at your peril...... Must have AC sync or it will burn..

[@geronimostade8279]

I missed the part where you sychronized the both driver stages to each other... this is actually the same way you self recommend not to do, isn't it?

[@CSHUNT83]

Couple years late. I had to re-watch myself. At around 9:30 he looks up the part number for the output stage and notes that the output transistors are rated well above the 800watt output desired. That's when he decided that just supplying sufficient dc voltage to the output stage should accomplish the results. very nice hack. i have have tore these down but did not realize that it was 120 dc that was chopped up to a square wave, should have followed the traces to the diodes.

[@codyaustin3728]

i have that exat same battery but two of them those are 12v alarm back up batterys

[@stellarp.9355]

If i need to run 120V appliances what size or how many W inverter do i need? is 400w inverter good enough?

[@haydentuttle9870]

Stellar P. Volts * Amps = watts You need to know how many amps you need to know how many watts

[@JasonMasters]

Just add up the wattage of all the things which you want to run, and then add about 10% for safety. Get an inverter which can handle that wattage. Also make sure that if you have inductive loads (fridges, fans, drills) connected to the circuit, that the inverter can handle the peak load drawn by these devices when they start up (typically 2x their normal running wattage). Most inverters have a "peak" wattage and a "continuous" wattage rating, so you can use this to figure out whether or not it can handle what you want.

[@Mike_Greene]

"A fool starts too early" . . . lol 1:33

[@jsmith6259]

Yeah I totally agree about you saying about make you something correct we have the same do something right or don't do it

[@hydroalternation]

What happens to phase when not in sync

[@cctv9794]

WHAT ABOUT THE TRANSFORMER ,BY DOING THIS YOU USE ONE TRANSFORMER ONLY AND THAT WILL EXCEEDS THE POWER RATING FOR TRANSFORMER ?

[@chriscollins9377]

add some copper wire to the solder to increase amps.

[@mikeriverajr4447]

can you split phase these?

[@plojm123]

What if you eliminated ground all together and made a wire two Male ends (one plugged in each inverter) and one female socket where both blacks and both whites come together.. wouldn't that take about 400 from each. Worse case two separate battery banks but I don't even that you need that

[@daniellange4772]

No. If they were 90 degrees out ofphase youd have double voltge

[@plojm123]

@@daniellange4772 guessing there is no easy way to make the 90 out of phase

[@daniellange4772]

@@plojm123 point is itd be double voltage not double current. Which means youd have more than 110 and lessthan 220 and current out cant be calculated till you know thevoltage. With the phase wrong itll lose more to heat and likely burn up a few FETs.