[HH] UPS batteries

[Tom Metro]

Jack Coats wrote:
> I do monitor all the UPS I can...

I've underutilized monitoring. Like a decade ago when I had more
infrastructure running Windows than Linux, I hooked up the cables and
ran the software (OPTI and APC). It was buggy and provided a
disappointing amount of information.

I haven't bothered hooking up monitoring to any of my Linux servers. The
effort didn't seem justified, given that the impact of an uncontrolled
shutdown is usually insignificant. (If the power outage outlasts the
battery, you've got bigger problems.)

If I thought I could get SMART-like pre-failure warnings from it, then
it might be worth while. Do you actually get analog battery health
metrics from your monitored UPSs? Not just a post-failure "bad battery"
indication?

It would be great if you could see a graph of battery voltage over long
time periods. Or discharge curves from the battery test cycles. (Most
UPSs don't seem to run a periodic battery test. My large OPTI, which is
currently out of service, did. I have read that it is bad to test your
batteries frequently, but the built-in test only ran for a few seconds.)

Ideally the UPS should test the battery every few days, capture the
discharge curve, as well as the charge current required to recharge it,
and distill that into a battery health metric that it reports back to
the monitoring computer.


> ..expect 3 years of service.

Right. As I said, the expected minimum life. But typically they last longer.

I have some UPSs in a remote location that I replace on schedule. The
rest I wait until the UPS trips a battery fault and then deal with it.

I do wish that all UPSs had a mechanism to silence the battery alarm.
Usually when it trips, I have to either swap out the UPS for another one
I have previously refurbished, or temporarily move the equipment over to
a power strip. The bigger UPS do have alarm silencing mechanisms.

Eventually I'd like all th UPSs I use for servers to be wired for
monitoring, and support hot swap batteries. It really seems to defeat
the purpose to have to shut down equipment to change batteries. Even
some of the UPSs I have that do support hot battery swaps electrically,
they aren't mechanically designed to make it practical.


> ...plan on replacing UPS about every 6 years...for UPS I put on our
> TV/DVD Players, etc.

I have some "power strip" style UPSs that I use for phones and A/V
equipment that are on the 2nd or 3rd battery. I don't see the point in
replacing the UPS itself until it fails. The downside to a UPS failure
for those devices is minor. The surge protection shouldn't be diminished
with age.


> Our power is still 'iffy', brownouts or surges 2 to 4x/month on the
> average.

For a few years someone in my neighborhood had some oversized equipment
that would glitch the power daily, and caused my OPTI UPS to switch to
battery (apparently bad enough that the AVR circuitry couldn't
compensate). This led to premature failure of the batteries. This went
on during summer months most days around the same time in the morning. A
big whole-house A/C unit, I assumed. I was rather annoyed that NSTAR
refused to do anything about it,


> ...they did protect the equipment...even after a close lightening
> strike (about 400 ft away).
> ...they did what we asked.

Indeed.

 -Tom