Smart-UPS 1500 turned into... a 12V inverter?!

[@jordanadams2187]

Sweet project, you certainly put more effect into it than I would! I have a set of 4 APC 1500’s (Various models but all the same style floor unit) that I intend to connect to a 24V LiFePO battery bank to be used with solar to recharge them off grid. If ever needed, a single one of the UPS’s could be connected to mains to charge the bank (Not 100% on that not cooking the UPS’s battery charging circuit due to overcurrent though)

[@koryyyy]

I'm a middle level electronic hobbies, and I laugh at "little simple modifications". hahaha Thanks for the video!

[@kiskiller3]

wow i didnt think of tdoing that modification, but i like the 24v system since it uses less amps soo cheaper cables and everything... but a 12v unit is alot more versatile thanks for the video!

[@leviahamefula3994]

Wouldn't it be easier to use a voltage doubler to step up the battery voltage to 24v?

[@lifeai1889]

Finding a 240a voltage doubler is harder then u night think

[@toobglued]

why would you want to cover to 12 v system when it runs cooler on 24 .. half the current. ?

[@tuyenphanminh1416]

Thanks! Anh What's about UPS Santak 1KVA CK1?

[@ahmadkhalidhotak9399]

I have APC smart-ups 1000 model, with the identical second transformer, where should i connect the parallel 56K resistor on this specific mainboard ?

[@basilkasimi2646]

Is ups safe for fridge use or freezer if converted to an inverter

[@TechnicalAlrounder]

How to check gate drive of this ups, sir in my apc smart 1500 ups gate drive of +ve chennel is missing results no output how to repair this problem please help me.

[@toniodebono8473]

Hi , I have a 24volt ups and I am trying to use it as an constant inverter using 2x 12 volts car batteries but the ups only last for 5 minutes and switch of automatically, I've checked the batteries and day are supplying 25.5volts on load, does the ups has an internal timing?and if so can I modify that or eliminate the timer? Thanks

[@Attohertz]

Are these circuit modifications applicable to the SMT1500 model? (USB and rj45 instead of DB port)

[@DJTrainR3k]

Oh man I love that inrush on your 2nd startup!

[@RockMan-tx2cn]

Hi FFcossag, Nice work. I would like to convert an APC Smart UPS 1400 (White Color) to an UPS that only takes one 12v battery. From your description, it seems to me that your changes solve 12VDC to 120VAC and the control part to take a 12V battery. How do I take care about the battery charging part(charge 12V battery and prevent from over charge)? or does your modification by adding the resistor already take care of the charging part? Thanks.

[@FFcossag]

My modification destroys the UPS capability of the unit, since it breaks the AVR functionality, making the UPS throw an alarm and shut down if connected to the grid. I'm about 80 % sure that it's possible to make it work properly, but I haven't checked it out, I'm afraid.

[@RockMan-tx2cn]

+FFcossag would you will be interested in figuring it out? It will help a lot to many people.

[@FFcossag]

Rock Man I'll probably look at it at some stage, when I have time and inpiration. If that's in a month or a decade, no one can tell.

[@RockMan-tx2cn]

+FFcossag would the following scheme combining your modification work? Add a 1/2x dc step down between the charger and the battery. Add a 2x step up on the sensing line between the battery to the circuit controller(then no need to add the resistor to fool the control circuit). And the do the rest of your modification on the output end. Thanks.

[@FFcossag]

Rock Man Sure, but I don't see why you'd do all that when all you need to do is swap a resistor. That would not fix the AVR issue, if that's what you're thinking. That's got to do with the transformer windings and how they connect.

[@wb5rue]

I have one of these that charges the batteries properly, it will go into test mode properly but when it is turned "on" the relays click and then it powers down and all of the LEDs flash. Any ideas? APC won't give me the time of day...

[@deansmith2784]

ok i added the 56k resistor and will add a 1-2 ratio transformer , i have NOT ADDED ANY MOSFETS OR CAPACITORS . Will It power on ?

[@arunouseph4793]

Dear FFcossag, Do you have the Circuit details of the UPS ?

[@hannonm]

put a Current inrush limiting circuit into the power supply.

[@kamaliasc]

hello, i have a smart UPS 1500, i use it as a solar power inverter. it works for 8 hours and then it turn off. (no overload) i should re operate it again at every time. is there a possibility to modify it so that can work as a solar inverter with pure sine wave. (working without stopping) ?

[@FFcossag]

I'm not sure, I haven't toyed with it. You could try adding increasing the external battery packs variable through the programming terminal.

[@kamaliasc]

it works normal for two days sometimes, then it gives alarm and shutdown. even if the batteries are almost full, i will try the terminal that you suggested. thank you

[@richmadrid9563]

Hi FFcossag, can you please tell us how and where did you connect the wires of the exhaust fans inside the Smart UPS? Also what are the mods that you did to make it run cooler and more efficient?

[@FFcossag]

I'm afraid I don't recall, this was so long ago.

[@DoogieLabs]

Do you think it would be possible to use two transformers with the low voltage side in series and use a 36v battery bank?

[@FFcossag]

No, but you could do 48 (and that's literally how APC do their 48 V UPSes too).

[@spongygryphon]

This is really cool and interesting research, thanks!

[@nimalweerasinghe4576]

hi, need small advise, will it possible to use old online UPS to recharge Lithium iron Battery pack and use as inverter as option as well?

[@FFcossag]

You can't just replace the battery, no.

[@gondorwaller3442]

i am currently in the process of setting up a solar system, and am debating whether to arrange the batteries for 24v or do this mod. according to my understanding, 12v will use double the amps and waste more energy as heat in the wires and transistors, while letting the two transformers run half as hot as one would. that would let you use better mosfets and improve the low voltage side without worrying whether the heart of the machine, the transformer(s), would burn up, letting you really reach its maximum rated potential. the alternative is to put the mosfets and two transformers in direct parallel, essentially overrating the power components, and let it run at 24v as intended, gaining increased efficiency while easily reaching its max rated potential and being reliable. another is to leave them as they are and do what you can to balance the load between them so neither is pushed too hard. what are your thoughts on this?

[@gondorwaller3442]

...or would each transformer get as hot as one driven by 24v due to increased losses by running at half the voltage, resulting in no operational benefit other than being able to take 12v, at the cost of twice as many equally hot components that need to be cooled? off topic, but would it be worth it to stack transistors and transformers still on 24v to increase output watts?

[@FFcossag]

You always want as high a battery voltage as possible. If 24V is an option, do that. If 48V, do that. These UPSes don't make very good solar inverters, though. Consider them an ugly hack rather than a proper solution.

[@ItsiliyaphoneXayavong]

Hi, I am interested in turning my apc smart-ups as an inverter, but it does consume a lot of current (without load). Do you know a way to solve this issue?

[@FFcossag]

No, you can't fix that.

[@josepeixoto3384]

@@FFcossag Put a inductor in series with the + input wire ; 2x PC40 material,OD~~50 or 60mm wind 30 or 40 coils of 3x3 mm2 (~~10mm2); so,2 TORIDS together,you may even epoxy them side by side before winding // i am just a hobbiest,i HAVE NO CONFIRMATION that this works, but i am ALMOST sure it does ,giving the place i saw it at , a youtuber in Thailand,very knowledgeable greetings from Portugal

[@uxwbill]

This sort of redesign is exactly the kind of thing I'd like to understand better.

[@FFcossag]

+uxwbill In this particular case, there really isn't much to understand. The entire design process can be summarised as follows: "Can you run this off of 12 V if you just put two transformers in series?" "Hm, it won't turn on. Maybe if I fool it to think it has a 24 V battery?" "Oh it works perfectly now. Let's fill up all the empty holes on the heatsink labelled "transistor"" And then about two days of trying to figure out how to get around the horrible, horrible thermal issues it has. Before I figured the battery voltage divider hack out, I actually planned to just use a 24 V boost converter to fool it, but due to long China shipping times, I ended up doing it "properly".

[@raym9691]

you and me both! I've dissected many of these are doing was looking at their boards with unpopulated areas and always wondered about that... I use the term infamously coined at power up "smoke test" !

[@ZulqarnainUlHassan]

How can be no cold start issue be solved. I mean the UPS won't turn on unless it is connected to AC source. Is there any way to solve the issue?

[@DescubreAntigua]

Perhaps not the answer you expected but try another brand or model. I played around with a few with the same issue, and found some old models turning on with no issues without AC current, just the battery.

[@bastianinostroza1150]

Same issue but I'm trying to use one as an inverter in a solar panel configuration. Looks like it calculates the amount of remaining battery by battery use time and no by voltage, so even with plenty of battery charge remaining it shuts down by itself.

[@anwaarqureshi3658]

Same issue here please make a video how to bypass these time calculation settings.

[@DavidSmith-dm8ew]

Can you modify it to run off your 48V solar setup?

[@FFcossag]

+David Smith The short answer is yes. Technically, this modification could be done to adapt one of these to 12 V, 24 V or 48 V operation depending on how you wire the transformers, but going up in voltage also requires new filter capacitors and higher voltage inverter FETs to be installed. I'm also not sure how the buck converters powering the electronics would fare; they might need modification or a step-down converter to be installed in-line.

[@DavidSmith-dm8ew]

+FFcossag that would just take all the fun out of it...lol

[@harryo3711]

How would you disable the charger?

[@FFcossag]

I'd turn the voltage down in the serial terminal using the apctest utility in apcupsd.

[@harryo3711]

@@FFcossag So I turned it up to 28v, but the ups is still carrying my 24.5v battery up to 25.4v 5a, so do it just ignore my commands?

[@FFcossag]

It doesn't go endlessly low. If you want to really drop the voltage, you'll probably have to reverse engineer the charger a bit and do it in hardware. I'm afraid I haven't done that.

[@harryo3711]

@@FFcossag I think my problem is that the charger is not a seperate part of the board, that I can just cut off. It is the same circuit that is doing inverter function as is the charger.

[@vinnieb571]

Can the same thing be do with a smart1000rm2u?

[@Arnthorg]

Nice, I have an old APC 1500VA ups that I would've wanted to convert to 12v. I have another UPS from compaq that's similar in size, do think that the transformer from that might be able to do the job? -Arnþór

[@FFcossag]

Unless it's an APC rebrand, I would not think so. The reason this works is because the transformers are identical, so you get exactly twice the winding ratio.

[@andrepato84]

hello friend, do not understand English, but I was quite interested in this modification, would have to describe step by step how can I do this in my NOBREAK SUA1500I APC SMART- UPS 1.5 KVA , I am very grateful.

[@АлексейДегтярев-и6э]

Hello! It is very good project!!! I trued to repeat it, but I have a problem, my smart UPS 1500 made on 640-7732h rev 9, can you help me and tell where I need to add 56k?

[@FFcossag]

Sorry, I don't have any specific info on that board.

[@deansmith2784]

what if i used a 1-2 ratio transformer before the current reached the original transformer would it power on ,as i am having trouble finding another ups transformer

[@FFcossag]

That would work, but you need a very beefy one at that.

[@deansmith2784]

can it be modified to run off a single transformer? while still utilizing the 12v setup

[@FFcossag]

No.

[@A.Seferovic]

good job, can u send me shematic of apc 1000 .if u have.. i will try to repair my olt two peaces

[@GlennWehe]

like your videos mate from the US, Montana...

[@FFcossag]

Cheers.

[@Cheese_1337]

Can a smaller APC ups like 350 or 475 be used as car inverter??

[@FFcossag]

Yes but only for

[@Cheese_1337]

FFcossag And if i put a fan on its side?? cutting hole of course xD

[@FFcossag]

mmmomg stopfkinglyin' It'd make it better

[@Cheese_1337]

FFcossag Like doing it your way, like putting fan on it, soldering extra copper on big traces, but can i run it continously without modifying ic side?

[@Megabean]

pretty cool, do you get the full VA output?

[@FFcossag]

+CreativeType Close enough, at least. I haven't really tested it with any weird loads, but the Smart-UPS 1500 is specified for 1500 VA or 980 W, and you saw it do well above that in the video.

[@Megabean]

+FFcossag ah cool, I might do this for my sailboat. You'd be scared how expensive they can get for marine quality 900w+ inverters.

[@FFcossag]

CreativeType Getting 900+ W out of this continuously and RELIABLY probably requires some pretty serious beefing up of everything around the power transistors, and I'm not sure how hot you'd have the transformers running.

[@Megabean]

+FFcossag it depends, I haven't measured the electronics. Im assuming it would be a continuous load of at least 300 watts when id use the system. it would only run when the motor is on however. There are certain things that would use more current for short periods. I'm planning on making it a live aboard so there's a few more things then the casual sailboat requires.

[@Megabean]

+FFcossag it depends, I haven't measured the electronics. Im assuming it would be a continuous load of at least 300 watts when id use the system. it would only run when the motor is on however. There are certain things that would use more current for short periods. I'm planning on making it a live aboard so there's a few more things then the casual sailboat requires.

[@danielauen7790]

I have a Minuteman Enterprise E 2300, it has a 48v battery connection on the back, the datasheet I found on it say it has "Scalable Unlimited Runtime via External Battery Packs" www.sizemyups.com/specs/1011/90000432/BR/0/ any idea on how to switch it from preferring to run on mains to preferring to run on the batteries until they get to low?

[@FFcossag]

No, why on earth would you want to do that?

[@Reg-th6zq]

Did I read on the APC website that these have a 97% efficiency

[@FFcossag]

When running on the grid under full load, yes.

[@jamest.5001]

OK .I think I get it. Without the extra transformer it would only be half output? If it would work. I would like to get alot more out of my apc 1500 aside from caps and transformers I don't know how much that would help. Would it make it go crazy if the traces were beefed up with flywires? I guess solid copper soldered to the PCB would be best. I would like to get 1500-2000watts from my ups. I know that's basically double the output. I was thinking maybe add a transformer in parallel and add MOSFETs. Also I was thinking about using the driver to build a inverter . maybe a high surge capable 2000-2500 watt and surge to 5kw. For 30sec. I know I'm probably dreaming especially with my skill level. I have the transformer from a huge forklift batt charger! I'm thinking rewind it and we'll build a huge inverter with the ups electronics orchestrating the deal! I need a pure sine wave ups I guess. I don't want to put all the effort in to a modified sine wave inverter. I'd just buy one before all that craziness. The inverter to do what I want will caust $2000 or so. I was thinking maybe build a separate board with a ton of FETs on it. And fet drivers resistors. Parallel that to the UPS FETs or drivers. Maybe trick the ups to thinking all is normal. I know its going to be huge and crazy looking. It's a crazy project. I gathered some parts I could maybe use. Some huge heat sinks. The huge transformer. It's 277/480v in and like 250a out for 48v batts. Or I have a smaller one for 24or 36v 100a. I want to oversize the transformer and winding gauge to help with surge. I probably need some help from someone who actually knows what's going on. Anyway I'm rambling. great video. I had thought about using a small inverter to drive the mess. Like a 300w pure sine wave. I don't know if it will ever actually get started or even work. I would like giving it a try!

[@FFcossag]

Getting an APC to drive such a huge transformer COULD be done, but you're probably looking at quite a few blown FETs in the design process ... Also load regulation will be a bitch.

[@jamest.5001]

FFcossag I was thinking maybe if the output winding is a heavier gauge with a large transformer core. Basically a transformer with twice the current output capacity. The voltage may not drop as much under load. Helping it be more stable. I know it will be load dependant without regulation. I'm just thinking it would be easier to regulate. Do you think my theory is correct?

[@FFcossag]

APC UPSes are PWM regulated, so if you change the output xformer too much, they'll probably behave quite erratically.

[@deansmith2784]

ok i added the 56k resistor and still nothing

[@andyjack2368]

I have ups 350 what I do I change battery on it have 4 12 volt lead acid battery 3 12 volt 7.2A and 1 20A lead acid battery running it I turn it on at 11:36am time I lot at it 1:07pm still going am running my dell laptop and speaker I plug in and I have 12 volt cooling fan running not death yet 🥰🥰🥰🥰🥰

[@UmbreWolf]

Good video, I knew there was a way to do it on a few of the 24v ups's. Thinking I might do this with my SU1400NET. "Pretty much the same thing you have in the video but its white and rated for 1400VA instead of 1500.

[@FFcossag]

+umbrefawx The white units should be even easier to work with than the black ones - I don't remember where the voltage divider resistor is on those, though. It might be an idea to replace the MOSFETs on those as well, since they're going to be older and higher resistance.

[@UmbreWolf]

+FFcossag Yep I did, I went a step farther though. I replaced the mosfets with completely different ones and populated everything else. The link to gate idea on the extra mosfets do work but for higher loads. I find connecting an equal vaule resistor to them works just as good, just connect the resistor to the gate drive where the first one is connected too, works a bit better and it does give a decent efficency increase near max load.

[@UmbreWolf]

+umbrefawx But As far as mine I did not do that cause I had to change out different vaule resistors entirely. (Since I replaced all the Mosfets with Diffferent ones. (Higher current rated, about half the RDS on time as the ones that where in there. I also changed out the heatsink on it with a bigger one I scapped out of a bigger unit. It runs at its full load just fine but I can't get it to stop entering overload when I push it beyond its rating. (Even though it should be able to do doub le that. Ive done it before just this ones a little diffferent and I forgot how I came across it.

[@FFcossag]

umbrefawx Yeah, the only power sensing is done on the 230 V side, so there's no wonder it thinks overload. You'd have to modify the feedback system there too to make it do more power - although unless you do the dual transformer thing, the trafo's gonna go up in smoke on you, heh. Good to hear about your hack though - may the spirit of the Smart-UPS be forever with you.

[@UmbreWolf]

+FFcossag I already switched out the main Transformer already. (Put in a bigger one of the same rating just to advoid that, however my model of UPS's are a little diffferent. The output on all of mine is 120v, not 240. I live in American you see and we have this stupid split phase system down here. (Our 240 service is split into 2 phases of hot, so on our 240 volt appliances, we have 2 lives and a neutral, and everything else is 120 to neutral.) Even though its not too different, different enough to make it harder on me. (240 is so much more easier to work with) But still having the 120v model should make it easier to run on 12v. (Or you would think) I know moldifying the feedback curcuit is an option, but these transformers are wound a little differently then the 240v models, and ive done it once before without having to modify the feedback curcuit, just can't remember how I "Fooled" it last time.

[@tyronenelson9124]

A UPS is actually already an inverter.

[@FFcossag]

Indeed, the reason we don't usually call them that is because they tend to explode if you put a big enough battery to them.

[@josepeixoto3715]

No good, i am just a hobbiest, but 2 main reasons i found 1--- those 45 watts at idle 24-7 will kill your battery 2-- those tranformers are POS (2nd only to microwave's...) , they are meant for short runs ONLY,the core area is small, good for 400 watts sustained, the 220 volt windings have SMALL number of turns,(hi amps!!) and they overheat, the one i tried i had to abandon and i built me an inverter (3000W,hi freq, 24 khz, EGS002, 18 watts idle.. do NOT reccomend those chinese parts either...)

[@adventurious1234]

Nice....

[@SaifudinSaifudin-h8h]

Ada menjual aisi K411

[@Alexelectricalengineering]

Thumbs up :) Alex

[@nosaltiesandrooshere7488]

👍

[@josepeixoto3384]

thanks for the video, still, it is hard at first to understand what you say,u speak too fast i guess; of course english is not my native language... (Portugal + 18 years in NYC..)) edit: OOPS!! i just found that the CC are on; thanks 2nd edit lol the CCs did not help much at all,the mavhine could NOT understand you fully,either anyway i got the idea, mine is 24 V and i have a 24 V BAT system,so..simpler

[@deansmith2784]

ok . i think i can make one .