Is it worth buying a replacement battery for a UPS or better to buy a completely new UPS? I have heard a UPS is never the same after the original battery dies and is replaced.

Is it OK to use a third party after-market replacement battery or should you always go with the original manufacture's replacement battery?

My question is specifically about the APC XS 800 (a small business/home UPS) but I'm interested in your thoughts about UPSs in general.

  • The statement "never the same after the original battery dies" is worthless without a reason. If the replacement battery is incorrectly specced then this will of course cause problems, but if it is correctly specced then there is no reason for the UPS to suddenly misbehave with a new battery.
    – RoG
    Commented Aug 22, 2018 at 9:09

4 Answers 4


I've never heard about replacing a battery causing the UPS to never be the same. The only UPS units that I've ever seen are just sealed lead acid batteries that wouldn't cause issues with the UPS electronics unless they weren't specced right (proper voltage and amperage rating). I've used APC and third party batteries and had luck with both. The third party batteries are generally cheaper so that is the way I would go. You don't need to replace the UPS unless there is something inherently wrong with the UPS electronics.

  • +1 for just replacing the battery. The UPS itself shouldn't need to be replaced as often as, say, a workstation. I haven't had good luck with 3rd party batteries though...the common issue with them seems to be swelling. The battery will go bad and I can't get it out of the UPS. Has happened with a couple different 3rd party battery mfrs, but never with APC brand.
    – user78940
    Commented Jun 12, 2011 at 17:05
  • If you do buy 3rd party replacement batteries be sure they're equivalent sizes. I recently shopped for a replacement battery for an APC 1300VA UPS. All the 3rd party batteries I saw were called "compatible" but listed an capacity (amp hour?) rating equivalent to the low end 1000VA model in the family. These batteries were also sold as compatible with the 1500VA model that was the top end model in the family. I assume they'd work as long as you weren't maxing your UPSs load out; but you'd only get the run time of the low end model. For an equivalent rated battery I had to buy genuine APC. Commented Jan 16, 2012 at 19:21

I would say that it's definately worth buying a replacement battery. Not to mention is probably better on our environment if you're only changing the battery and not the entire unit.

  • +1 A replacement battery from the original vendor should a don't care to the UPS electronics. Of course, my vendor is currently recommending that I replace the entire UPS (it's oooold).
    – Bob Cross
    Commented May 17, 2009 at 18:32
  • I agree- the controller is solid state, so I don't see how a legit replacement battery could possibly cause trouble. Commented May 18, 2009 at 0:34
  • Except that they age and get dusty like everything else. 3 UPSs that we replaced batteries in burned out (with sparks and smoke) within 3 months of the battery replacement.
    – Jay R.
    Commented May 19, 2009 at 18:36
  • 3 months later? Time for a new UPS vendor. We've done several battery replacements with no issues.
    – kmarsh
    Commented Jun 29, 2009 at 12:19
  • If the UPS was not abused, and less than 10 years old I agree. Older UPS controllers / inverters may be less efficient than more modern ones, but you need to consider the specifics in the particular case.
    – mctylr
    Commented Mar 6, 2010 at 22:39

We've replaced the batteries in our oldest UPSes 3 or 4 times, and I don't see any reason not to keep them going for a while longer. These are a 5U form factor, 3000VA, 120V input and since it doesn't look like they're available any more, I hope they keep running for a while.

We have about 8 of the smaller 1200-1400 VA SmartUPSes and over the years the electronics on 2 of them have failed, but other than that we've replaced the batteries in those a few times as well.

I've bought 3rd party SLA (sealed lead acid batteries) for my electric bike, but it never occurred to me to look for UPS batteries from those suppliers. Next time we need replacements, I'll look into it. As far as I know, there aren't a lot of secret design techniques for SLA batteries, so I'd expect batteries with the same ratings to be just as good no matter where you buy them from.

  • The batteries in UPSes are almost universally completely standard size and spec lead-acid batteries, as they are cheap and easily obtained. The UPS manufacturers just like you to buy from them as they charge a lot more. Commented Jun 29, 2009 at 15:05
  • We've had a few CyberPower UPSs that have silenty failed on the charging end. Brand-new batteries replaced just months before and we got just seconds power out of them when the building main popped. They are 1000w AVR units, but the load was never showing anywhere near peak and so shouldn't have been using battery power to supplement.
    – Magellan
    Commented Jun 15, 2011 at 14:54
  • This may mean nothing. As in: you got 2 bad loading Systems - good. Bad luck ;)
    – TomTom
    Commented Oct 7, 2012 at 14:54

Industrial UPS usually cost 2 times more, seems logical that they would last longer. APC's web site says to change your UPS if its 5+ years old. i've seen a few forum where people replaced capacitors and MOV's to squeeze more time out of their's, but i wouldn't try if you've never had basic electronic training.

If the 5+ years old seems a bit early for an equipment that cost so much, its probably a conservative estimate of when the caps are going to start failing.

I've had just one cap fail on my APC Back-UPS XS 1300, and my PC's power supply failed just after a few repetitive power drop out. (That's usually when you figure out you have a problem with your UPS right?)

i'm more of an hobbyist though but i think that even if the repetitive switching from inverter to main, along with a bad cap, could've caused my issue, its also possible that a simple surge got through to my equipment. i'm also wondering if the switching itself could've caused a surge, i might eventually buy a Probe 100 Plus from Powertronics so i can detect a failing UPS in the future.

MOVs being what they are, sacrificial surge protector, you might want to look for a Series Mode Filter to protect your UPS from surges as well. i've been looking at the products from Zerosurge and the technology looks pretty nice. I'm also replacing my UPS, i'm not taking any chances...

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