APC Back-UPS battery

[PlainName]

Got an APC Back-UPS 1400 which doesn't do anything. It did before I left it in a corner for 3 or 4 years, and that occurred because the owner complained that it sometimes turned the PC off.

So, thinking I would sort it out I have it apart and see a battery pack comprising two batteries en bloc connected in series. No markings to identify what the batteries are. There is 14V across them: one is measuring 10V and the other 4V. So 12V batteries and the charger would be putting around 24V into them.

Power up the UPS without the batteries and look at the battery leads. There is 13VAC there, which suggest the batteris are 6V each! But... a 6v battery can't read 10V so that seems a pretty solid clue. But 13V is just too close to being a decent 12V battery charge (bit low, perhaps, but it's AC) and where APC uses 12V batteries they are usually in parallel, so without the 10V reading I would have gone for 6V batteries.

Anyone know either what the batteries should be, or how to tell if they are 6V or 12V?

[Ed.Kloonk]

Is this it?

https://www.apc.com/shop/my/en/products/APC-Back-UPS-1400VA-230V-AVR-Universal-and-IEC-Sockets/P-BX1400U-MS


https://www.apc.com/shop/my/en/products/APC-Replacement-Battery-Cartridge-113/P-APCRBC113

[gnuarm]

Ed's photos show the caps on each cell.  So the ones in his links are 12V, 6 cells x 2V each.  Do your batteries have the six caps? 

But you should not be measuring AC on the battery leads.  What is that about???

I recently worked on a lead acid charger and the chip we had picked sensed when the battery was too low to be charged at full rate, then it would trickle charge at a very low current until the voltage came up.  I'm sure 14V is too low to be charged at full rate.  Since you are measuring with no battery connected they may be pulsing the power.  If the power to the battery is truly AC, going positive and negative, I'd say your charging circuit it bad.

[Monkeh]

But you should not be measuring AC on the battery leads.  What is that about???

Lack of smoothing. Rectified and slammed into the batteries without a care in the world. It's a cheap APC UPS after all, their business is in selling batteries.

[gnuarm]

But you should not be measuring AC on the battery leads.  What is that about???

Lack of smoothing. Rectified and slammed into the batteries without a care in the world. It's a cheap APC UPS after all, their business is in selling batteries.

If that's what he is seeing fine, but that's not AC.  It's DC with an AC component. 

[pqass]

Alternate source for RBC113:  https://www.upsbatterycenter.com/apc-rbc113-compatible-replacement-battery-pack


You can confirm the correct battery for your unit by choosing "UPS BATTERIES" menu, "APC Back-UPS" item, and drill-down from there.
Be sure to use the name on the front of your unit. eg. Back-UPS XS 1300

[Klondike Mike]

DON'T cheap out and buy a non-APC branded battery. Just like buying ANYTHING Chinese, you risk burning down your house. Spend the extra required for the brand name and have peace of mind that it won't catch fire and burn down your home with you in it. 

[wraper]

DON'T cheap out and buy a non-APC branded battery. Just like buying ANYTHING Chinese, you risk burning down your house. Spend the extra required for the brand name and have peace of mind that it won't catch fire and burn down your home with you in it. 

Certainly buy non APC branded battery. As they usually are cheap Chinese crap as Kung Long sold at 4x the price. You will get overpriced CSB if lucky. Buy CSB, Yuasa, Panasonic or whatever good quality battery you can get at reasonable price.

[Monkeh]

DON'T cheap out and buy a non-APC branded battery. Just like buying ANYTHING Chinese, you risk burning down your house. Spend the extra required for the brand name and have peace of mind that it won't catch fire and burn down your home with you in it. 

Don't be daft. There are many good battery manufacturers and APC aren't even a manufacturer.

[james_s]

DON'T cheap out and buy a non-APC branded battery. Just like buying ANYTHING Chinese, you risk burning down your house. Spend the extra required for the brand name and have peace of mind that it won't catch fire and burn down your home with you in it. 

If you peel the APC sticker off of the battery, you'll find it's whatever cheap brand they could get that week. The only reason to buy an APC batter is if you've got money to burn and are feeling charitable to APC. I've had reasonably good luck with Power Sonic batteries, there are only a few companies that actually make small SLA batteries though, they get labeled with dozens of different brands.

I've fixed probably 20 UPS's and every single one of them just had bad batteries and nothing else wrong with it. Every one I've fixed also had 12V batteries, either one or a series pair.

As far as safety, UPS's can be dangerous, but if it's going to burn your house down it's not going to be the battery that causes that. I've seen the MOVs catch fire more than once, power surges are rare here and MOVs are marginally useful under the best of circumstances so I usually remove them.

[pqass]

If you peel the sticker off you won't likely find an ampere-hour rating.  I've never seen one on APC branded batteries.
It will probably state its nominal voltage and chemistry (sealed lead-acid).

Then measure the size (length width height) of your battery and compare it to other sealed lead-acid batteries of the same size.
From that, you'll get the ampere-hour rating.  And don't forget the terminal/lug size too.

Then go buy a battery from your choice of vender.  Good brands: Yuasa, Panasonic, Interstate. 
I've also used lesser brands: Power Patrol

[natman69]

They are two 12V 9Ah sealed lead acid batteries in series, with 6.3mm connectors. I am sure because I have done manteinance to this UPS in the past.

I can suggest to replace with a battery that can supply high current for short period, designed for UPS application. I use FIAMM 12FGH36 but you can use any brand with same specs.

 

[PlainName]

Is this it?

https://www.apc.com/shop/my/en/products/APC-Back-UPS-1400VA-230V-AVR-Universal-and-IEC-Sockets/P-BX1400U-MS


https://www.apc.com/shop/my/en/products/APC-Replacement-Battery-Cartridge-113/P-APCRBC113

Yes, that's the one. And that's the cartridge. But what is the cartridge?

[PlainName]

Ed's photos show the caps on each cell.  So the ones in his links are 12V, 6 cells x 2V each.  Do your batteries have the six caps?

Yes, same. They don't appear to be actual caps so I figured they could be just molding marks and didn't want to rely on them.

[PlainName]

But you should not be measuring AC on the battery leads.  What is that about???

Lack of smoothing. Rectified and slammed into the batteries without a care in the world. It's a cheap APC UPS after all, their business is in selling batteries.

If that's what he is seeing fine, but that's not AC.  It's DC with an AC component.

Confession time: that's not what I'm seeing. At least, not now.

I had inadvertently removed the battery power connector after dismantling (forgot at the start), so the negative lead of the meter was floating. No power gave no reading and turning the mains on showed 13VAC. Duh.

Fixed that now and I get an actual DC reading of 4V. However, I get that with no mains too, so not sure wtf is going on - perhaps some capacitor holding a charge, but why bother when there's a BFO battery at the end of the wire? Whatever, it makes much more sense now (in the way it doesn't change). Sorry to have laid a false trail...

[PlainName]

They are two 12V 9Ah sealed lead acid batteries in series, with 6.3mm connectors. I am sure because I have done manteinance to this UPS in the past.

I can suggest to replace with a battery that can supply high current for short period, designed for UPS application. I use FIAMM 12FGH36 but you can use any brand with same specs.

Thanks very much

[james_s]

I actually have a dead APC battery cartridge right here that I saved for rebuilding with new batteries so you can see exactly what they are. Oddly they don't have the Ah rating but this physical size is standard and comes in 7.5 and 9Ah variants. Note the "HR" in the part number, that indicates High Rate, although one battery manufacture I contacted a while back stated that all of their batteries are built as HR, so who knows. If you look up the datasheet for a reputable brand like Power Sonic you'll see that the ratings are pretty much worthless in a UPS application. At the full rated load you'll get only a small fraction of the stated Ah capacity and even at more sensible levels you will get nowhere close. The capacity printed on the battery is assuming something like a 10 hour discharge which you will never get, even with no load plugged into the UPS at all. They abuse the hell out of the batteries even under the most ideal of conditions.

[madires]

Certainly buy non APC branded battery. As they usually are cheap Chinese crap as Kung Long sold at 4x the price. You will get overpriced CSB if lucky. Buy CSB, Yuasa, Panasonic or whatever good quality battery you can get at reasonable price.

Long time ago APC used also Panasonic SLAs in their battery packs. Only the standard types, not the ones specifically designed for UPSs.

[EHT]

The only thing slightly tricky, at least in the Smart-UPS 750s that I have is that the 'cartridge' is two batteries glued together with a wiring harness & fuse. Often the UPS is eBayed without the battery for obvious reasons, but then you might be missing the wiring harness. It has a special plug which allows the pair of batteries to side into the connector on the UPS chassis. Might be a bit of a pain if you don't have one off the old batteries...

FYI, I used Yuasa Y7-12 for the Smart-UPS 750. Decent brand and *way* cheaper

[james_s]

The only thing slightly tricky, at least in the Smart-UPS 750s that I have is that the 'cartridge' is two batteries glued together with a wiring harness & fuse. Often the UPS is eBayed without the battery for obvious reasons, but then you might be missing the wiring harness. It has a special plug which allows the pair of batteries to side into the connector on the UPS chassis. Might be a bit of a pain if you don't have one off the old batteries...

FYI, I used Yuasa Y7-12 for the Smart-UPS 750. Decent brand and *way* cheaper

That's the reason I saved this dead cartridge I have, it's the most convenient way to store the other bits. If you are buying a used UPS it's worth asking the seller if they're willing to yank the hardware and wiring off of the batteries, otherwise you might have to buy an OEM cartridge and then re-cell it next time around. I'm not a fan of the cartridge format in general, it makes swapping batteries by non-skilled users marginally easier but most people seem to just buy a new UPS anyway judging by the number of perfectly good ones with dead batteries that I've been given.

[m k]

My experiment is that differences start showing when batteries are in "wrong" orientation.

Some models last pretty short time.

[james_s]

A lot of UPS's really cook the batteries too, they charge them aggressively to get the low cycle time, and they use batteries that are grossly undersized for the stated rating of the UPS. I've also had some batteries that were defective right out of the box.

[CJay]

A lot of UPS's really cook the batteries too, they charge them aggressively to get the low cycle time, and they use batteries that are grossly undersized for the stated rating of the UPS. I've also had some batteries that were defective right out of the box.

That's been my experience, if you have an outage that lasts long enough to result in scripted shutdown (I.E. takes a decent amount of charge out of the batteries) the kind of size UPS you would fit in a rack with the servers tend to cook the batteries while recharging.

They don't survive many cycles of that.

The building UPS on the other hand...

[james_s]

I think at some point we'll start seeing a lot more UPS's using lithium iron phosphate batteries. Those are far more tolerant of the sort of high discharge rate experienced by the typical UPS. A LiFePO4 battery with half the rated capacity of the Pb counterpart will likely provide higher real world capacity in that application in addition to much greater cycle life. IIRC with a 30 minute discharge a SLA battery gives only about 50% of the rated Ah capacity which is specified for something like a 10 hour discharge. You'll NEVER get a 10 hour discharge with a consumer UPS.

[CJay]

I think at some point we'll start seeing a lot more UPS's using lithium iron phosphate batteries. Those are far more tolerant of the sort of high discharge rate experienced by the typical UPS. A LiFePO4 battery with half the rated capacity of the Pb counterpart will likely provide higher real world capacity in that application in addition to much greater cycle life. IIRC with a 30 minute discharge a SLA battery gives only about 50% of the rated Ah capacity which is specified for something like a 10 hour discharge. You'll NEVER get a 10 hour discharge with a consumer UPS.

They're out there but they're *expensive*.

The design goal for most UPS isn't to run stuff for hours, just long enough to get everything down safely or to get your standby genny up to speed.