I had a UPS battery die today. I guess better today than tomorrow during a potential power outage. I pulled the battery and confirmed it was reading low - 10-something volts.
What bugs me is that the battery was last replaced in June 2009, so it is just over 3 years by a bit. That's generally considered the minimum lifespan for a SLA. It hasn't been particularly stressed. Only once fully discharged, to my recollection. The battery was a bit on the warm side when remove. It's possible the charge circuit might have failed and isn't regulating the current properly. According to my notes (an email complaint to the vendor), this battery was part of an order that came poorly packed, and showed some physical damage to the battery (bent terminals). It's possible it had some internal damage that contributed to its short lifespan. Another possibility is that the Universal Power Group manufactured batteries, which is what has ended up being at the best price point the last few times I've ordered replacement UPS batteries, just aren't up to the same quality standards. Anyone else noticed problems with Universal Power Group (UB) batteries? Do you have a favorite battery vendor? I've possibly had other problems with Universal Power Group batteries ordered around that time. On that same 2009 order I bought a batch of 3 batteries to go into a larger UPS, and a month later ordered a pair of batteries for another UPS. In both of these cases, the UPSs failed to function correctly after the batteries were replaced. I went as far as pulling the batteries and checking the voltage, which was within the expected range. I had enough other functioning UPSs at the time that I didn't dig any deeper, and just put the batteries aside for future use. But I was left feeling rather suspicious of the batteries. I could see the electronics in one of the UPSs failing, but it seemed a bit more than coincidental that both would be bad. (Each was taken out of service at a different time. I believe both indicated a failed battery.) I'll have to take a closer look at them someday. I'll charge the batteries first, and monitor battery voltage and current to see if the charger circuit is working properly. (Has anyone else noticed that typical UPSs make it very difficult to distinguish between a battery failure and an electronics failure? Once the battery voltage drops below some threshold, most UPSs seem to act flaky and the warning lights and power switch behavior becomes erratic. I've seen this on several APC models, and I believe on some other brands as well. When I first ran across this I thought he electronics were fried, but tried a good battery anyway, and was surprised to see it magically start to behave normally. Seems like a pretty stupid design. Logically, the electronics should be powered by both the AC and the battery through isolation diodes, and should operate normally, even with no battery installed.) I grabbed one of the batteries from the July 2009 order that happened to be the same size as the small UPS uses, and the voltage checked out. Theoretically you're supposed to charge SLAs about once every 3 months to keep them in good condition, which I hadn't been doing. Given the battery is already 3 years old and hasn't been properly stored, I guess I shouldn't expect much life from it, but for the time being it is working. -Tom _______________________________________________ Hardwarehacking mailing list Hardwarehacking@blu.org http://lists.blu.org/mailman/listinfo/hardwarehacking