People say that "local" UPSes (uninterruptable power supplies) reduce the life of their batteries while other, "branded" UPSes are better and do not affect the battery life.

I have noticed that a battery with a "local" UPS lasts only 2 years, but batteries with "branded" UPSes (in which good technology is used) last 2-and-a-half to 3 years.

My question is: A UPS consists of an inverter and charger (along with other things I have not mentioned), so how can a bad UPS affect its battery life?

  • 2
    \$\begingroup\$ Are they the same batteries? I'd expect a cheap UPS to have lower quality batteries as well. \$\endgroup\$
    – pjc50
    Jan 8, 2013 at 15:20
  • \$\begingroup\$ yes batteries are same, i have compared my ups(with same batteries) with my relatives UPS which is imported and have a company tag( i cant remember the company name but it has same batteries as i have) \$\endgroup\$ Jan 8, 2013 at 15:35
  • \$\begingroup\$ It will depend greatly on the battery being matched to the UPS's expectation/design. This is like asking why a poorly designed or unsuitable battery charger would damage a battery. \$\endgroup\$
    – John U
    Feb 8, 2013 at 9:16

2 Answers 2


I do know that even the quite expensive ones (rack-mount 3kVA APC) tend to destroy batteries.

The reason UPSes kills batteries is that in an UPS you(or the manufacturer) prefers to have faster charging of the batteries than long lived batteries. In practice that means the the charger part of the UPS charges the battery with a higher voltage than the voltage a normal charger(build for "normal" use, that is something more like longevity)

At the few discharge cycles an UPS battery usually has, it should last way over 2 years (say 10 maybe?). The common type of batteries is UPSes is AGM or adsorbent glass mat. This type of battery survives a larger number of deep discharges than most flooded batteries and AGM also has the pro of being storeable in any position you like it to be at.


Answer yes absolutely the quality of the UPS can alter battery life.

Any quality UPS should do a periodic self-test. For APC kit it will normally click and clunk for 10-15 seconds every 2 weeks from when it was powered on. A UPS that does this should get 5-6 years off its batteries before they need replacing.

A budget UPS will not do these tests itself. Some can be forced to do a battery test by software, but that relies on the user setting up said monitoring software and connecting a serial/USB cable.

Secondly, a good UPS will have a fan for when the inverter is operating. A budget UPS tends to skimp.

So a budget UPS with 1-2 12V batteries will get about 2 years.

HOWEVER the budget UPS won't tell you when the batteries are expired. Your first clue might be a tiny flick in the power, enough to make the UPS jump in but not enough to upset non-UPSed gear.

The UPS makes a leap onto battery, but it finds theres nothing in the battery, so it turns straight off and takes the load with it. The UPS can generally be turned back on and services resume, but its only function is trim of overvoltages. In this state, it has no reserves and can't boost a low voltage, and can't carry the whole lot in the event of no utility.

Example "budget" UPS (this model is rebranded by multiple companies, and retails for about $100)

Image has been edited to remove branding - multiple companies add their own branding.

By comparison, a quality UPS is a brand name, and if new costs 10-20 times as much as the budget one. Your requirements should dictate what kind of UPS you choose - sometimes a budget one is the right thing to have.


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