UPS Battery replacement help

[er557]

just snagged a pair of these from amazon for my vesta ablerex 1500L

Amazon.com: SPS Brand 12V 9Ah Replacement Battery for CSB Replacement Battery HR1234W Replacement Battery (Replacement) - 12V 9AH Version -from SPS : Health & Household

Buy SPS Brand 12V 9Ah Replacement Battery for CSB Replacement Battery HR1234W Replacement Battery (Replacement) - 12V 9AH Version -from SPS: 12V - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

will replace by guides from youtube

Ablerex Electronics Co., Ltd.

www.ablerex.com.tw

 

[John Naylor]

Again, laptop batteries have nothing to do with UPS batteries. Amazon sells CR2032 and deep-cycle marine batteries too. Does that make them relevant to this topic? No.

And note I did mention Amazon as a source to check in my post #5 above. But I will point out they do NOT always have the best price as prices change frequently. So again, it is important to check other sources on the day one is ready to purchase. Also Amazon only delivers them faster if the cells you want are in the current inventory of one of their nearby distribution centers.

I thought this topic was about buying a UPS battery. I said: "Since then I been [buying] UPS batteries using Amazon" ... where's the beef ? If you wanted to criticize, cuda pointed out I left out the word "buying" or perhaps "getting" . Can you quote the part of the post where it was indicated that there is any similarity between laptop and UPS batteries other than you can buy both at the same place. No you can't cause it isn't there. Doubling down implying it is doesn't change the written word.

I spent two paragraphs talking about UPS batteries. In the 3rd paragraph I provided a bit of background on what led me to consider Amazon as a source of UPS batteries. I included this because when I 1st heard it, it seemed odd and it was not something I had ever before considered.

1. I never considered buying any type of battery from Amazon, never would have entered my mind.
2. When I went to order a laptop battery replacement from our custom laptop builder (an individual I have known for about 10 years and know something about his knowledge and hobbies) and he suggested Amazon. When I expressed a considerable level of incredulity ... he went on to explain that ya can buy any type of battery @ Amazon ... cars, boats, motorcycles, ATVs, UPSs, power tools whatever .... and they provide next day delivery.
3. So I bought the laptop battery there and later on when the need arose, remembering his earlier recommendation regarding "all types of batteries" I went and took a peek about what Amazon had to offer and as was said .... "Since then I been [buying] UPS batteries using Amazon"

The fact is I never would have thought to to look at Amazon for UPS batteries if not for the laptop guy's recommendation ... a recommendation that included all types of battery replacements. I design water treatment plants ... does that make any recommendation I make on these forums off topic ? How is it that when you provide suggestions on where to buy a UPS battery it's relevant and when someone else does it's not ? I did not recommend that OP purchase a laptop battery, I specifically recommended he consider Amazon as a source of UPS batteries ... so in what way is this irrelevant ? I'm as lost here as I was with the weather map and black sharpie explanation on TV. How does the fact that someone I have known for 10+ years recommended that we use Amazon for any / all types of batteries make anything irrelevant ? In what possible way does battery design restrict who can sell it ? Which of these is acceptable ? Only one ?

After my laptop supplier suggested I consider Amazon as a source for all types of batteries, I looked into it and "since then I been getting UPS batteries from Amazon"
After "Ask Woody" suggested I consider Amazon as a source for all types of batteries, I looked into it and "since then I been getting UPS batteries from Amazon"
After "my electrical contractor" suggested I consider Amazon as a source for all types of batteries, I looked into it and "since then I been getting UPS batteries from Amazon"
After "my mother-in-law" suggested I consider Amazon as a source for all types of batteries, I looked into it and "since then I been getting UPS batteries from Amazon"
After "Bill Bright" suggested I consider Amazon as a source for all types of batteries, I looked into it and "since then I been getting UPS batteries from Amazon"

Yes, we all agree that there is little similarity between the design of a laptop battery and a UPS battery ... but as such was never stated or implied, why do you see it as justification for irrelevancy ? How does the fact that "a guy who builds laptops for a living " recommended I consider getting any / all types of batteries from Amazon make my actual experience buying UPS batteries there and recommending them as a source of UPS irrelevant ?

Yes, I'm sure its possible that a particular battery might not be available. The relevant facts however are, in my experience:

a) No other supplier I looked at offered any indication of delivery date. Amazon said "next day". Everyone else was vague on when it might be delivered with "usually 2-4 weeks" being the most common statement. To my mind, that's extremely relevant as not many folks want to go without a UPS during Hurricane season for "usually 2 - 4 weeks".
b) By your own statement "all of the sources you listed" had only 1 year warranty, I'd think the option for a 3 year warranty (4 with AMEX) would be relevant to most purchasers.
c) I did look at other sites ... I was unhappy with the warrantees, unhappy with not knowing when I'd get it....unhappy that i had to 'add to cart" before i could get any information at all.
d) Yes, Amazon might not have a particular model number in stock, but most of the other sites had few choices and when they say 2 - 4 weeks does it matter if it's in stock ... is it in stock, if it is why so long ? However, there were dozens upon dozens of alternative choices of varying warrantees, brands, etc you can see on screen. Remember, a large % of these purchases are via storefronts. Given the number of dollars coming in thru these storefronts, rest assured that every vendor has Amazon listed as a higher priority than any of us.

By all means shop at various sources, I always do ... I looked at other sites ... but no 3 year warrantees, no guaranteed next day delivery. I'm not saying look only at amazon, I'm saying don't leave Aamzon off ya list of places to check.

 

[silkstone]

Laptop batteries use a totally different technology (lead acid vs Lithium Ion) and there are a totally different issue and totally irrelevant to this topic for many many reasons.

UPS use industry standard "SLA" 6 or 12V batteries. Laptop batteries are always proprietary and of course, are typically Li-Ion and come in all sorts of different voltages, shapes and sizes.

As for Amp hour ratings being higher, that is not a problem. You can always go higher there but not lower. It is the voltage that must be the same. FTR, several of my UPS came with 12V7Ah batteries. When time came to replace them, I put 12V9Ah cells in there. The advantage is significantly longer run times.

So I finally got around to opening the UPS. Inside there was only 1x 9Ah battery, but space for 2.
I bought 2x 7.2 Ah batteries as there is space for a second battery in there. Do you see any problems if I connect these 2 new cells in parallel? They should add to 14.5 Ah or so.


I'm assuming I'd just have to watch/compare the power input and heat before using it.

Should the two batteries, apart from being identical, be at similar charges before hooking everything up?

I believe it. Those transformers are heavy as hell.

I'm betting it only takes one, the 1400VA model takes the APCRBC113, which is two RBC17 batteries.

You were 100% correct.

UPSes don't really care much about what battery you put in them as long as they are the correct voltage. I've seen units modified with cables running out of them connected to full on car batteries. The only spec that matters is voltage, and most of them either take 12v or 24v(two 12v in series). You obviously have to worry about size too if you want the battery to still be inside the unit. But all the other specs don't really matter, just voltage and maybe size.

I've read some forums advising people not to go with too big a battery. . . well not hooking up a second battery in parallel. Do the charge characteristics of bigger batteries matter very much?
Just thinking how big of a deal it will be going from 1x battery to 2x batteries.

for reference. This one is what mine looks like inside (the bigger one):

This

and this

are the 2 battery versions

 

[Bill_Bright]

Inside there was only 1x 9Ah battery, but space for 2.
I bought 2x 7.2 Ah batteries

Do you mean 12V 9Ah and 12V 7.2Ah? That is, are you 100% sure the old and new are the same voltage?

Batteries in parallel add current so it should work fine - just triple check your strapping and verify with a meter that you are outputting the correct voltages BEFORE connecting to the UPS. You don't want to accidentally connect a 24V battery to the charger.

Should the two batteries, apart from being identical, be at similar charges before hooking everything up?

No, that should not be necessary. But if one is fully discharged and the other fully charged, it would not hurt to strap the batteries, then let them sit for about 30 minutes to give them a chance to "level out" before connecting them to the UPS charger.

I've read some forums advising people not to go with too big a battery. . . well not hooking up a second battery in parallel. Do the charge characteristics of bigger batteries matter very much?

The problem with going with a bigger capacity battery is when discharged, they are going to demand more charging current. In a really cheap and poorly designed (or faulty) charger, that might result in the charging circuits getting too hot. But if you consider a "trickle charger" often used on car batteries - those are tiny chargers connected to monster batteries and they don't have any over heating issues. They just take a lot longer to fully charge the battery.

If the new battery demands too much current all at once, the charger "should" simply shutdown. Assuming your new cells are good and there are no internal shorts, I doubt that will be a problem. APC is not known for cheap, poor designs.

 

[silkstone]

Do you mean 12V 9Ah and 12V 7.2Ah? That is, are you 100% sure the old and new are the same voltage?

Batteries in parallel add current so it should work fine - just triple check your strapping and verify with a meter that you are outputting the correct voltages BEFORE connecting to the UPS. You don't want to accidentally connect a 24V battery to the charger.

No, that should not be necessary. But if one is fully discharged and the other fully charged, it would not hurt to strap the batteries, then let them sit for about 30 minutes to give them a chance to "level out" before connecting them to the UPS charger.
The problem with going with a bigger capacity battery is when discharged, they are going to demand more charging current. In a really cheap and poorly designed (or faulty) charger, that might result in the charging circuits getting too hot. But if you consider a "trickle charger" often used on car batteries - those are tiny chargers connected to monster batteries and they don't have any over heating issues. They just take a lot longer to fully charge the battery.

If the new battery demands too much current all at once, the charger "should" simply shutdown. Assuming your new cells are good and there are no internal shorts, I doubt that will be a problem. APC is not known for cheap, poor designs.

Yeah, both types are 12V. I confirmed via a voltmeter that the terminal voltage is around 13.8 V and identical for each.

I actually just browsed their website and found that they do sell a 9 Ah version, which wasn't offered, but also a 14 Ah, which while is wider, will fit if I cut out the center compartment divider.
For what I understand, going with a single 14 Ah battery would be better than 2x 7.2 Ah ones in parallel.

 

[Bill_Bright]

For what I understand, going with a single 14 Ah battery would be better than 2x 7.2 Ah ones in parallel.

I don't see why - except for less chance the user making a strapping mistake. I personally would not want to be cutting up my UPS.

Remember, even these batteries are made up of cells. So while those 2 x 12V 7.2Ah batteries are batteries, they become two cells in a single battery when strapped. My point being, that 12V 14Ah battery probably has a couple more cells internally. In other words, same difference.

As far as what ultimately would be better - that would be to get the proper replacements from the start.

 

[Grog6]

If the 14Ah battery fits, it will work fine.

There are issues with hooking two separate batteries together; the voltages my not match, so one cell will discharge the other one, causing heat.
This happens when a charge cycle ends, so it may or may not be a problem.
It's riskier than one larger battery.

If you go with the larger battery, it will hold up power longer.

I've fed a UPS from a large car battery, it lasted for over an hour.
You just have to use large enough cable (same size as internal wiring to the battery) to go to the external battery.

 

[Bill_Bright]

There are issues with hooking two separate batteries together

Nah! It is common practice to use multiple batteries or cells to make one big battery. All my UPS use at least 2. My biggest uses 4 x 6V 7Ah batteries strapped in series parallel to make one big 12V battery.

As I noted previously, all these SLA batteries are already made up of multiple cells internally - most often 6 x 2V cells in series to make the one 12V battery. No way each of those cells are producing exactly 2.00V. They are all slightly different but "level off" to about 2V.

Common flashlights use 2, 3, or 4 cells. Many trucks and boats use 2 x 12V car or marine batteries. Laptop batteries are made up of multiple batteries (cells).

In this case, as long as they are rated for the same voltage, it is fine. And the OP said they were both 12V. The only way one will discharge the other is if one is bad or shorted out completely. Otherwise, they will simply level each other out.

 

[silkstone]

Nah! It is common practice to use multiple batteries or cells to make one big battery. All my UPS use at least 2. My biggest uses 4 x 6V 7Ah batteries strapped in series parallel to make one big 12V battery.

As I noted previously, all these SLA batteries are already made up of multiple cells internally - most often 6 x 2V cells in series to make the one 12V battery. No way each of those cells are producing exactly 2.00V. They are all slightly different but "level off" to about 2V.

Common flashlights use 2, 3, or 4 cells. Many trucks and boats use 2 x 12V car or marine batteries. Laptop batteries are made up of multiple batteries (cells).

In this case, as long as they are rated for the same voltage, it is fine. And the OP said they were both 12V. The only way one will discharge the other is if one is bad or shorted out completely. Otherwise, they will simply level each other out.

In series, it shouldn't really matter. The EMF of each cell will just add up and the amount of charge in one cell shouldn't have any effect on another. The batteries are all 6 cells in series.
Good to know that there are actually UPS' that have their batteries hooked up in parallel, up to now, i'd not found anything and so was a little more worried about doing it myself.

I'm more worried about the end of life, when hooking them up in parallel, rather than it all working initially. Currently, the EMF of each cell is identical when fully charged, and it remains stable down to an estimated 20%. When the batteries dry up/wear out is more of a concern. If one battery ages quicker than another, or if one ends up dying earlier, then any energy in good battery would be converted to heat in the second. If hooked up to the mains, and the UPS doesn't have a way of catching this, then I'd be worried it'd be a potential fire risk.

An example of what I mean. One of the batteries dies, giving it a much higher internal resistance and lower terminal voltage (I'm not 100% sure whether the terminal voltage drops in dying batteries or just the load voltage) while the second (good) battery retains a 12 V terminal voltage. The good battery continually works on charging the bad battery to balance the terminal voltages. Then the UPS notices the overall voltage drop and tries to charge them both, converting all that energy to heat in the first battery.

For that reason, I'm going to try and swap out one of the batteries I have for a 14 Ah one, then break the internal plastic divider (the separator between the gap for the 2 batteries) and hook that up inside). The wires 'should' be long enough to accommodate the new battery and I've checked that the internal dimensions of the space fit the battery, with a little room to spare down the length.
The second battery, I'll just swap out for a 9 Ah battery to keep as a spare for when another of my UPS' need it. My place of work also has a bunch of old, dead UPS, and I may ask for one so I can replace the battery and use it on a different system.

I'll post pics of the modification I do and post it here. Unfortunately, It's a dumb UPS, so there aren't really any charts or stuff that I can generate

 

[Bill_Bright]

In series, it shouldn't really matter. The EMF of each cell will just add up and the amount of charge in one cell shouldn't have any effect on another.

Regardless if strapped in series, parallel or in some series-parallel configuration, this all assumes these cells are in proper working order and have no internal shorts.

Good to know that there are actually UPS' that have their batteries hooked up in parallel, up to now, i'd not found anything and so was a little more worried about doing it myself.

There are dozens if not 100s of different UPS on the market designed for all sorts of uses and intended loads, from small life-support monitoring devices, to full large scale, whole facility UPS. How the batteries are strapped is determined during the design, based on the intended use. I do not recommend changing how an UPS battery is configured unless one has a basic understanding of how batteries and UPS work.

If one battery ages quicker than another, or if one ends up dying earlier, then any energy in good battery would be converted to heat in the second.

No sorry, but you are making assumptions based on more assumptions (and "what if" scenarios) you really don't fully understand. Batteries fail for a variety of reasons and the resulting symptoms are often very different. For example, if an "open" occurs with one of the cells in a series strapped battery, no current will flow. No current means no heat at all.

There's really no such thing as a dumb UPS though some are certainly smarter than others. All UPS have to at least be smart enough to detect a mains power outage in order to kick over to battery power. And all UPS have to be smart enough to prevent running on battery until 0% charge, and to prevent overcharging.

Any decent UPS "should" detect a fault in the battery and/or should have thermal protection features built in to prevent an over heating scenario. Some UPS simply refuse to turn on and/or charge the batteries. Others will refuse to kick over to battery power should mains power go out. Others will alarm when a fault is detected.

Years ago I used to maintain air traffic control radio systems and our transmitter and receiver sites had whole facility UPS that maintained power during a power outage, hopefully long enough for the backup generators to fire up, stabilize and kick in. The battery rooms had about 40 marine 12V batteries strapped in series parallel configurations to make one big 48VDC battery. And once a week, we had to take hydrometer reading for the specific gravity of each cell in each battery. This was a real PITA, but at the same time, it allowed us to detect and replace a failing battery before it actually failed. Of course having open cell batteries presents it own set of health concerns (fumes, lead exposure, acid burns) and fire risks - hence the reason car, marine and UPS batteries are all "sealed" lead-acid batteries today.

 

[silkstone]

Regardless if strapped in series, parallel or in some series-parallel configuration, this all assumes these cells are in proper working order and have no internal shorts.
There are dozens if not 100s of different UPS on the market designed for all sorts of uses and intended loads, from small life-support monitoring devices, to full large scale, whole facility UPS. How the batteries are strapped is determined during the design, based on the intended use. I do not recommend changing how an UPS battery is configured unless one has a basic understanding of how batteries and UPS work.

No sorry, but you are making assumptions based on more assumptions (and "what if" scenarios) you really don't fully understand. Batteries fail for a variety of reasons and the resulting symptoms are often very different. For example, if an "open" occurs with one of the cells in a series strapped battery, no current will flow. No current means no heat at all.

There's really no such thing as a dumb UPS though some are certainly smarter than others. All UPS have to at least be smart enough to detect a mains power outage in order to kick over to battery power. And all UPS have to be smart enough to prevent running on battery until 0% charge, and to prevent overcharging.

Any decent UPS "should" detect a fault in the battery and/or should have thermal protection features built in to prevent an over heating scenario. Some UPS simply refuse to turn on and/or charge the batteries. Others will refuse to kick over to battery power should mains power go out. Others will alarm when a fault is detected.

Years ago I used to maintain air traffic control radio systems and our transmitter and receiver sites had whole facility UPS that maintained power during a power outage, hopefully long enough for the backup generators to fire up, stabilize and kick in. The battery rooms had about 40 marine 12V batteries strapped in series parallel configurations to make one big 48VDC battery. And once a week, we had to take hydrometer reading for the specific gravity of each cell in each battery. This was a real PITA, but at the same time, it allowed us to detect and replace a failing battery before it actually failed. Of course having open cell batteries presents it own set of health concerns (fumes, lead exposure, acid burns) and fire risks - hence the reason car, marine and UPS batteries are all "sealed" lead-acid batteries today.

So I added 2x 9Ah batteries to the UPS. I had to break the center partition to make sure it would all fit. Joining/reconnecting the wires also meant that it's 'squished' a little bit, but they are heavy duty wires so it shouldn't matter.
I checked the power input while charging 1 battery vs. 2 and it is pretty much the same, 40 Watts. It all seems to have gone well so now I have a 18 Ah UPS

 

[Bill_Bright]

but they are heavy duty wires so it shouldn't matter.

I'd watch this. Crimped/kinked wires can create a resistance point where heat could build up. Plus, SLA batteries are known to swell a little when they get warm - and swell a lot when they wear out. If they swell too much, they will even crack and leak. Not good.

I am glad it works. The higher Ah rating should give you longer run times.

 

[silkstone]

I'd watch this. Crimped/kinked wires can create a resistance point where heat could build up. Plus, SLA batteries are known to swell a little when they get warm - and swell a lot when they wear out. If they swell too much, they will even crack and leak. Not good.

I am glad it works. The higher Ah rating should give you longer run times.

Yeah, if the wires get broken, but the internal wiring to the battery uses really really thick cable, aluminium I am guessing, that is around 3-4 mm in diameter. So thick, it wouldn't fit in the spade connectors I'd bought so I made a linesman's with the copper wire.. The extension wire I put in is designed to wire 240 V AC, 7 strands of 1 mm diameter copper inside. I also added solder to each connection I made, the splices and the connectors. I also gave a few wraps of 3M tape and the 1-2 layers of heatshrink around each.

I'll keep an eye on the swelling, there is still additional space in there, if they do swell. When I took the original APC battery out, I noticed it had leaked slightly as, while they were sealed, there were of the type with the circular plastic plugs at the top that can be removed to refill the battery. The replacements are completely sealed.

 

[Bill_Bright]

The worry is not about them getting "broken". It is about them getting pinched.

 

[Grog6]

You can't really refill a gel cell battery; most of the time, those plugs are there as a safety, to keep it from exploding under a bad problem, usually a charger failing.

Liquid batteries want water occasionally, gel cells just die.

 

[silkstone]

So with the 2 batteries in parallel the unit draws a constant ~20W from the wall, when nothing else is plugged in. It is also a fair bit warmer than my other single battery unit (same model).
Is this something to be concerned about?

 

[Bill_Bright]

UPS batteries are SLA ("sealed" lead-acid). They are not vented. They are intended to be "Maintenance free". They are not meant to be opened or refilled with water. In fact, because they are sealed, no water should evaporate out. If it does, that suggests a crack in the seal or case and the battery should be replaced. I note too opening sealed UPS (or car) batteries will typically void the warranty.

So with the 2 batteries in parallel the unit draws a constant ~20W from the wall, when nothing else is plugged in. It is also a fair bit warmer than my other single battery unit (same model).
Is this something to be concerned about?

How are you measuring this?

Did you give your new batteries in the UPS plenty of time to fully charge?

Some consumption is normal due to the UPS monitoring and regulation circuits which are active whenever the UPS is plugged in turned on - even if nothing is connected to the output side of the UPS. So in normal operation, some heat is also normal.

I just looked at the spec sheets for several APC and Cyberpower UPS and none list power consumption when sitting there doing nothing. So I don't know what might be considered normal. And sorry, but I am not prepared right now to shutdown any of my systems and reconfigure them to see what they do.

But I just felt 5 different UPS here. Two are connected to equipment that is up and running and 3 are connected to equipment currently in standby (sleep) mode. All have small spots that feel slightly warmer to the touch than surrounding areas, but nothing alarming. I don't know if yours is normal for that model UPS, or if you have a bad cell.

If you are sure your batteries have had enough time to fully charge (at least 8 hours should do it, you might take the cells out and feel them. Or better yet, use a IR thermometer to measure them. Are they warm? Are they equally warm.

Use a multimeter to measure and record their voltages. They should read a bit above +12VDC. Leave them out of the UPS for 24 hours and measure them again. The voltage should be almost the same and NOT drop more than a tenth of a volt or two.

 

[silkstone]

UPS batteries are SLA ("sealed" lead-acid). They are not vented. They are intended to be "Maintenance free". They are not meant to be opened or refilled with water. In fact, because they are sealed, no water should evaporate out. If it does, that suggests a crack in the seal or case and the battery should be replaced. I note too opening sealed UPS (or car) batteries will typically void the warranty.

How are you measuring this?

Did you give your new batteries in the UPS plenty of time to fully charge?

Some consumption is normal due to the UPS monitoring and regulation circuits which are active whenever the UPS is plugged in turned on - even if nothing is connected to the output side of the UPS. So in normal operation, some heat is also normal.

I just looked at the spec sheets for several APC and Cyberpower UPS and none list power consumption when sitting there doing nothing. So I don't know what might be considered normal. And sorry, but I am not prepared right now to shutdown any of my systems and reconfigure them to see what they do.

But I just felt 5 different UPS here. Two are connected to equipment that is up and running and 3 are connected to equipment currently in standby (sleep) mode. All have small spots that feel slightly warmer to the touch than surrounding areas, but nothing alarming. I don't know if yours is normal for that model UPS, or if you have a bad cell.

If you are sure your batteries have had enough time to fully charge (at least 8 hours should do it, you might take the cells out and feel them. Or better yet, use a IR thermometer to measure them. Are they warm? Are they equally warm.

Use a multimeter to measure and record their voltages. They should read a bit above +12VDC. Leave them out of the UPS for 24 hours and measure them again. The voltage should be almost the same and NOT drop more than a tenth of a volt or two.

It's measured with a well meter. I have exactly the same model UPS and it does not get as warm in it's original configuration, but it is definitely warmer on the top than the surroundings. I'll unplug everything connected to that one when I get chance and see what its unloaded behaviour is in terms of idle power draw.

They've had plenty of time to reach full charge. I'll take it apart again this weekend as well and see what the batteries read. If they have significantly different voltages, then I'll know that there is a problem

 

[Grog6]

The batteries are fighting each other; constantly overcharging one, discharging the other.

Pick the one with the highest voltage, and stick with it.

 

[silkstone]

The batteries are fighting each other; constantly overcharging one, discharging the other.

Pick the one with the highest voltage, and stick with it.

I checked the unaltered one I have and that also appears to draw ~18 W from the wall, though I've not had time to properly test, I will spend more time this weekend on it.
I'll also verify whether the voltages of the 2 batteries are identical or not.

 

[Bill_Bright]

The batteries are fighting each other; constantly overcharging one, discharging the other.

Pick the one with the highest voltage, and stick with it.

Yeah, that's what it sounds like. But it should be noted this is only a problem if the fully charged voltages are more than a few 1/10s of volt different.

I'll also verify whether the voltages of the 2 batteries are identical or not.

Slight differences are normal. But again they should be within a few 1/10ths when fully charged.

You need to check to see if they can hold a charge by testing them out of the UPS as I noted in my previous post.

As an example, I have a brand new 12V 8Ah SLA battery here. Yesterday at 11:01 my time, I measured the voltage and it said 12.83V. Today, just now, I measured it again. It measures 12.82V.

 

[silkstone]

Yeah, that's what it sounds like. But it should be noted this is only a problem if the fully charged voltages are more than a few 1/10s of volt different.
Slight differences are normal. But again they should be within a few 1/10ths when fully charged.

You need to check to see if they can hold a charge by testing them out of the UPS as I noted in my previous post.

As an example, I have a brand new 12V 8Ah SLA battery here. Yesterday at 11:01 my time, I measured the voltage and it said 12.83V. Today, just now, I measured it again. It measures 12.82V.

The voltage difference between the two is 0.01-0.02 V. They are both over 13 V so it doesn't seem to be an issue.

I opened it up and found the transformer to be really hot, when touching the iron core, it was a little too hot to keep my finger on, but not hot enough to burn. I removed one of the batteries and left it running overnight, this morning, I just checked and it is still really warm. Maybe I should be adding some sort of fan to the case of this.

On a side-note I got gifted a APC SMC2000L yesterday. It just needed the battery replaced and have ordered a new 36 Ah one. I'm just waiting for the adapter plugs so I can actually use it, it takes a server power cable (C20) and the rear has no regular style outlets, so I've ordered some plug converters (C14) I think I'll hook this thing up to my main rig.

 

[Bill_Bright]

opened it up and found the transformer to be really hot, when touching the iron core, it was a little too hot to keep my finger on, but not hot enough to burn. I removed one of the batteries and left it running overnight, this morning, I just checked and it is still really warm. Maybe I should be adding some sort of fan to the case of this.

I think you should return the UPS to its original, designed configuration. With fully charged, good condition batteries, the transformer should not get that hot. Something is not right. You don't want to risk a fire.

Oh, BTW. Just checked that battery again today and it still measures +12.82V.

 

[silkstone]

I think you should return the UPS to its original, designed configuration. With fully charged, good condition batteries, the transformer should not get that hot. Something is not right. You don't want to risk a fire.

Oh, BTW. Just checked that battery again today and it still measures +12.82V.

So I put it back in it's original config and it was still reading pretty hot. I moved it to another location and it's cooled down significantly so i think it's just a lack of airflow in the area.
I added the 2nd battery back in and will test it for a while like this and monitor heat.

With the single battery, in the new location, I was getting 65 C on the Iron core, measured with an IR thermometer, which seems reasonable.

 

[Bill_Bright]

65°C (149°F) is well above the threshold that would cause 2nd degree burns to the skin. That temp does not seem reasonable to me.

The UPS should not be placed in a confined space but it does not need to be in a place that receives a "flow" of cool air ventilation. It only needs to be placed where air can freely radiate off it.

I would not trust that UPS in my home.