[HH] UPS batteries

[Phil C.]

I'm not positive of the composition but I think the ups batteries are some
sort of lead acid gel type.  Unfortunately the only way to tell what
happened would be to dissect the battery and look at the electrodes and the
electrolyte.

-----Original Message-----
From: hardwarehacking-bounces+charlestek=rcn.com at blu.org
[mailto:hardwarehacking-bounces+charlestek=rcn.com at blu.org] On Behalf Of Tom
Metro
Sent: Sunday, October 28, 2012 9:56 PM
To: hardwarehacking at blu.org
Subject: [HH] UPS batteries

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
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