I have a 2000VA ups that contains 2 batteries ( 12V 9Ah ). I think that something happened to the batteries, since now they can barely handle an average laptop for about 3 minutes before shutting down the whole ups. there is any way to resurrect the batteries, or should I just buy new ones?


closed as off-topic by Kaz, Daniel Grillo, placeholder, Chetan Bhargava, Nick Alexeev May 26 '14 at 21:20

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  • 3
    \$\begingroup\$ Wow, that's a really wimpy set of batteries for an UPS that large. Are they original? A 9-Ah battery isn't really intended to support an 80+A load! \$\endgroup\$ – Dave Tweed Dec 27 '12 at 22:34
  • 2
    \$\begingroup\$ How old are the batteries? Was the UPS ever placed in storage for a long time? It sounds like either the batteries are end of life or the charger in the UPS is not working properly. \$\endgroup\$ – HikeOnPast Dec 27 '12 at 23:01
  • \$\begingroup\$ The UPS was bought 3 years ago, and when it was new, it was able to sustain my 700w desktop (at least for the briefly times I needed it during outages). I went to another country for the last 2 years but the ups was being conencted to the pc all the time, and my brother was using it from time to time, until I came back and noticed that the ups was not able to keep the computer online anymore. How can I check if the batteries could be still charged? should I unmount the batteries from the ups and charge them manually? how? \$\endgroup\$ – Terix Dec 29 '12 at 3:19

UPS batteries usually do not last much more than 3 years, it's that easy really.

To check the battery or batteries: As your UPS is a large one I'm assuming that it is actually has a separate battery compartment which you can access without dissembling the whole thing.

Connect as many batteries as you need in series to get 12V and load test it which a common 12V lamp.

Charge the 12V pack with a normal automotive charger. As there most likely are several batteries in that UPS, repeat for all batteries.


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