UPS - single points of failure

[markw at mohawksoft.com (markw at mohawksoft.com)]

>> I read this post and it made me think. I am a big fan of both Triplite
>> and
>> APC, having no problems with the units I have had for many years. Old
>> and
>> new work perfectly. I also did not see in this message what the exact
>> failure was.
>
> I did not diagnose the failure beyond the fact that it was *not* in the
> batteries, and that all 3 of the internal fuses were still intact.
> Something
> in the electronics failed, symptom was no-power.

I've dealt with litterally hundreds of these types of devices and have
NEVER seen a failure that wasn't directly battery related.

>
> I've had plenty of failures like this--particularly during my stint at
> Shore.Net--and it's almost never a problem with the batteries themselves.

Really, that's odd. Every time I've seen a failure, a battery replacement
fixed the problem.

> In
> my experience, gel lead-acid batteries don't seem to suffer from lack of
> maintenance (indeed, I'm hard-pressed to see any possible way to perform
> user-level maintenance on UPS units beyond throwing them out and replacing
> them every few years. ;-)

Every UPS unit I have seen, save for the injection molded type, have a
panel closed with a screw, on the back or bottom, that can be opened and
the battery removed and replaced.

It is true that the gel type batteries, themselves, require no
maintenence, but they do wear out. About 3 years is the best you can hope
for and still have a reasonable percentage of their "new" life. Remember,
this is an "emergency" power system, it has to have power for it to work,
you don't get rid of the battery when it no longer holds a charge, you get
rid of it when it is just below acceptable capacity.

The cheaper UPS systems also have cheaper batteries, so they don't last as
long. Also, lead acid batteries have a very bad behavior with deep
cycling, getting down to about 30% to 40% of charge is bad for the battery
and reduces its overall capacity.



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