Is this usefull what i'm doing ? UPS Battery's.

[Jism]

So a long time back ago, i bought a 2kva UPS which was dead on arrival. After opening it up, both battery's had a low voltage of around 9V or so which i assumed the item must have bin on the shellfs for quite a long time. I tricked the UPS by loading up a fake load, so it would start charging.

After the thing was charged up, i load tested it, and it coud'nt even run a 800W toaster knowing the unit has a approx 1000W for a minute or so. 800W should be really within and possible. I figured out that the battery's where toast, and decided to refill 'm with distilled water.

So far so good, but what i did'nt realise is that they where gel based battery's and not submerged ones. I flushed 'm out, and put stuff back together. However it did worked a bit from this point on because the battery's suddenly could take some load but not all.

I just gave up, knowing how i messed up the warranty and all that, i did'nt want to carry back a 30KG weighing unit lol and have it missing for 2 weeks minimum. So as i read about bringing battery's back to life; i read that charge > discharge > charge > discharge is a technique that does seem to work.

Now after 4 cycles and putting a light load untill the voltage becomes too low for the UPS to turn itself out; there's sign of life as the unit now can run a 1000W heater for just 5 seconds; normally it would instantly shut off. I just keep repeating the charge > discharge for quite a few times and it seems to bring back the battery's to life (it's 2x 12V > 24V) .

Do i need to repeat the above proces? Or am i wasting my time here? I'm not looking to eeze out the full intended performance, as long as it can hold 600W for at least a minute i'm happy already.

There's another weird thing; when i add a light load the UPS seems to give a voltage of in between 140 and 180V. When i add a more heavyer load suddenly you can hear it click and the voltage seems to be in spec of what it supposed todo. It's the usual bulb light test to assure my multimeter is'nt reporting a different voltage due to sine wave and all that.

The UPS was a replacement for a 600kva office thing; just was'nt sufficient for the PC that i was attempting to power upon powerloss.

 

[1freedude]

The batteries might be out of balance. One goes below useful depth of discharge befor the other. Can you charge them one at a time with an external charger? Let them sit off any charge for an hour or so and measure resting volts. Im guessing they'd be around 12.55 - 12.9 volts.

 

[Jism]

There's a 0.4v difference in between; one has like 13.8v and the other 13.4v; i charged and discharged them quite a few times, and it seems like the difference in between is getting smaller; more important it takes longer in between the charging cycles now so appearantly it's working what i'm doing.

 

[maxfly]

How much does a new set of batteries cost?

 

[Jism]

I dont know exactly, i think it was 40 to 60$ a piece. Currently there's 2x9A in there but i'd go for 2x 12A to extend its running lifetime.

 

[maxfly]

Ew not cheap then. Obviously i was wondering if it would be easier to just get a new set of batteries but it doesn't seem so
Unfortunately thats the extent of my expertise! Haha GL!
What exactly are you planning on running off of the ups? Just curious.

 

[Jism]

Was planning to run my computer with it. The country i'm in, sadly has often power dips to complete outtages just long enough to shut the PC down. A UPS was handy; however the 600VA thing was'nt capable of let alone running it while gaming or keep it up for longer usage.

2000VA (=1000w) should be more then sufficient to run anything i'm having hooked behind it. But if i could get half to 750W out of that with a decent time; i'm happy. Ill go for another discharge now, it just finished charging and the battery voltage(s) are around.

And yep; it seems to hold the 1000W heater now for at least 7 seconds before the buzzer kicks in about a low voltage.

It works.

I will order a new pair / set of battery's tho; bigger ones too of up to 12A which increases my running time with proberly 5 to 10 minutes.

When i pull the power cord while powering a complete PC + screen, the battery voltage drops from 27.1 (13.4v) to approx 25v and sits there (12.5v). I have'nt tested how long actually i could drive my computer; but it's enough so far to catch any dips or outtages for at least a few minutes.

 

[1freedude]

Try to charge the lower voltage battery up to 14.4, then float it at 13.5 for a day. That will increase the capacity and increase run time.

 

[Jism]

Bit difficult. The UPS is a 24V and not a 12V unit. So i cant just charge one independent battery. These are GEL AGM based ones; and you just cant hookup a normal battery charger to it either.

 

[Shrek]

2 KVA translates to about 1.2 KW

You will probably be needing new batteries.

 

[1freedude]

You can and you can. They're messed up as is, and a regular charger wont damage it. Think of it as putting another battery in parallel with the low voltage one. If you can get to the leads, do it. I would.

 

[Shrek]

I'm waiting for an excuse to replace lead acid batteries with lithium, but one needs to derate the power.

 

[Jism]

You'd say that Lithium would hold more power; but at this point it's still not. I saw a modder that basicly did a bunch of battery's inside such casing. He also changed the charging controller to support charging of lithium. Basicly the energy density should be better then AGM based ones; as the highest ive seen so far was up to 12A per battery. This one carries 18A per battery:

Pretty neat. I just woud'nt recommend it hacking out an old one with all the acids inside. Second you need large nikkel or even copper plating to hook up the battery's. If you dont do this right the battery cant keep up with the current and those spot welds will be the first ones to go. But 2x 18A sounds alot better then the stock 2x 9A or even 2x 12A. A mod like that inside a UPS, you need to adjust your charger for it. It's a different form of charging lithium vs agm (gel).

 

[Shrek]

I dont know exactly, i think it was 40 to 60$ a piece. Currently there's 2x9A in there but i'd go for 2x 12A to extend its running lifetime.

You sure the 9Ah and 12Ah are the same size?

The 18Ah lithium can take 18A max continuous, quite a bit less than a lead acid.

 

[Jism]

Yep; they are pretty much universal.

 

[yotano211]

You can build your own lithium battery system for pretty cheap. I built a 300ah 12volt system to go into a sailboat. I used lifepo4 batteries so there wouldnt be any thermal runaway.

 

[Shrek]

Yep; they are pretty much universal.

There are two common sizes; the width differs.

 

[Jism]

It's the left; which is most common for house/office type of UPS systems. Pretty universal. The highest ive seen was 12A or so.

 

[Shrek]

Do you have a link?

 

[Jism]

12V 12Ah Battery, Sealed Lead Acid battery (AGM), B.B. Battery BP12-12, VdS, 151x98x94 mm (LxWxH), Terminal T2 Faston 250 (6,3 mm)

12V 12Ah Battery, Sealed Lead Acid battery (AGM), B.B. Battery BP12-12, VdS, 151x98x94 mm (LxWxH), Terminal T2 Faston 250 (6,3 mm), BP12-12 ➤ APC Batterie ➤ APC UPS ➤ Gruppo di continuità APC© ➤ Batterie per UPS

www.battery-direct.com

Something like this. Thats i think the highest available size (12AH) you can get for that format. Ofcourse i could install 4 of them and increase the running time up to two times as long; but that would require lots of hacking inside the case and proberly make it one big fire hazzard. Not sure if the resistance for the charger would be too high for the UPS.

 

[Shrek]

That looks like the bigger one (the one on the right).

Smaller
151 x 65 x 94 mm

Larger
151 x 98 x 94 mm

If the end looks nearly square, its the bigger one.

 

[Jism]

Ok,

This is the last time i'm ever fucking around with UPS based battery's. Matter of fact i ditched the UPS outside for a good reason.

Appearantly both battery's are supposed to be within ~ 14.x V of of voltage that would make up to 28V or so. The charger of the UPS basicly keeps charging untill the desired voltage is archieved. Before i installed 'm back there was a small difference of 13.4v vs 14v. This usually means that one of the cells of the battery's can be showing signs of wear. For the last few days i had irritating eyes, a soar throat and even to the point that my vision became blurry when working. I thought i was tired or something. Yesterday the typical rotten egg smell appeared in my office. Till the point i decided to take the UPS appart. The connectors showed signs of (white) corrosion.

Hydrogen sulfide - Wikipedia

en.wikipedia.org

After reading this it all made sense to me. The battery's are bad and should have never bin re-used. My office is a bit ventilated but knowing i was sitting right next to it, a dangerous situation. I decided to throw out the UPS and will decharge the battery's completely today. I will order a new kit, but, put the UPS outside of my office completely, and have it in a well ventilated area to prevent any situations like this ever again. I know battery's can go bad, go bold or to some extend even explode (knowing the gasses are highly explosive when in packed concentration) but that it was deadly?

The dumb part of this: The UPS is programmed to charge untill a certain desired voltage. Now when you have one battery off with a few percent or simply lower maximum voltage that it can be charged to, you'll have the other battery that appearantly is in good condition being overcharged untill it reaches critical damage or simply heat. The heat is what makes this dangerous. It is appearantly produsing gasses at that point that are toxic and could even lead to death within just a few minutes of your subjected to a too large of a quantity in a small room.

Now my complaints where'nt that severe to my understanding, however the fuzzy eyes got me thinking to the point that something was up. And i was right. So if anyone is in the same situation, having half working battery's, or having battery's with a lower voltage then they should and your thinking of re-using them inside a UPS, please dont be stupid. Dispose these battery's as they should. The UPS itself is what makes this dangerous esp when the battery's are hooked together to make a larger voltage for operational. This is why it's advised to always replace both battery's and not just one. The difference in cell performance is what it makes it critical in here. The charger will simply continue to charge untill it reached the intended charge voltage. For a good battery this is just waiting for shit to happen. It is the bad battery in series what makes it such a dangerous thing.

I see all these people making these "bring your battery back to life" bullshit and honestly, a UPS battery is not to be fucked or re-used with with home baking powder soda or refill tricks. They emit toxic or even deadly gasses when used improperly. In a normal charging condition or using a charge controller you could fiddle around per battery or have the desired (best) voltage per unit. But this is'nt the case. I'm sure the battery's would have some lifetime in them but just not in the UPS and particular not in a closed room such as an office. So please people, dont be stupid. Luckily i sensed very quickly that something was off and i was right. Since i ditched the complete unit outside (in a storage) all my complaints are gone completely. It was going on for 3 days.

 

[maxfly]

Hot damn that is scary as hell man! Good to hear you caught it before anything awful happened.

 

[Jism]

Yes, it is scary to think of that a UPS is a potential hazzard to your life. It can happen with any UPS carrying a battery inside of it. Once cells go bad, and they are being overcharged, fumes start to emit. It is these fumes that even a little dosis of this can already be harmfull to your health. Initially you'll sense or smell a rotten egg type of thing. Smell it long enough and you wont smell it anymore. And thats where the headache and blurry vision starts to kick in. Sit long enough and you wont make it to tell the story really.

I knew that the gasses could be toxic, but sitting next to a leaking or slowly emitting one never appeared to me could be so dangerous!! There is no warning sign either and you see these idiots stripping the speaker from the UPS's PCB because it "makes a noise" .. dumbasses, it's there for a reason. The UPS only warns for too high load, a too low of a battery voltage or when it's running on battery backup. The UPS does'nt sense if a cell inside a battery goes bad. A battery is basicly 4 cells of each providing 3.6 volts. When you have just one cell off, it means a lower overall provided voltage. When you run 2 battery's to provide a higher voltage, basicly the weakest of the chain has bin increased 2 times now. A dumb charger basicly keeps on charging untill it reached the desired battery voltage, but in this proces you are hurting and overcharging the good cells far beyond their rated specification.

It bothers me that even in house or office based UPS's dont have a sensing that a battery might be due or a battery refuses to charge beyond a certain (set) voltage for a period of time. It is this what makes it utterly dangerous for cells to burn themselfs out and start releasing Hydrogen sulfide. I'm sure the battery's could have a longer lifetime, even if they where bad, but not inside a UPS that does'nt have a programmable charge controller that you could individually set a specific voltage per battery or per battery bank. I think i could technically telnet my way into the UPS using the USB since it does have a micro-controller, but then i'm adjusting a unit beyond to what it was build for.

The battery's however, did heldup far longer a 800W room heater for example. And it did run my PC in full load + screen + light + printer for at least a good 2 minutes. But i'm not going to take any risk at all anymore. UPS's are'nt cool toys, lol. Esp when the battery's go bad these things are utterly dangerous.

 

[TheUn4seen]

Just my three cents: Don't f.ck with AGM batteries. They really don't like to be disassembled - they have very thin plates and cushioning material which will damage your lungs once it dries and starts to crumble. If you get them dead by sitting for too long, you can "kind of" get them back up to working order by very slowly charging up to 14.8-14.9V, and by slowly I mean 150-200mA max, which will take a lot of time. You can do things like reverse or pulse charging to get the deposit off the plates, but that's better left to people who feel adventurous, know what they're doing or place very little value in their safety.
The good thing is they are easily recyclable so it's really better, even if not cheaper, to get new ones and recycle the old. You absolutely can use them, but not inside a badly designed UPS with no time limiter in the charging circuit, an absolute must for multi-battery system. I use my old AGM batteries for a crude spot welder and such, but charge them manually with a dedicated charger - one of the old "four button" chargers from Hobbyking works well, costs very little and has configurable cut-off voltage and timer.
AGMs won't catch fire like lithium batteries sometimes do unless you do something unusually bad to them, but they will vent some gases and generally become unreliable as they age and sulfur starts to deposit on the plates.