[TriLUG] reason not to mix batteries in UPS

[shay walters via TriLUG]

I've run across those problems as well - all the individual things you
mentioned at various times.  Depending on the construction of the UPS,
it can be a real challenge to get the battery packs out when they get
swollen.  I've become an advocate of replacement on a schedule rather
than waiting for them to die.  I think that when they get old they'll
accept a charge and get to a good voltage, so they "look" good to the
UPS, but have very little actual stored capacity, and by the time they
are showing failure in the UPS logic, they've been bad for a while and
they're getting swollen.  I try to replace on a 3-year schedule, but
I'm such a procrastinator that the actual dates end up more like 4 (or
5) years - that's why I try for 3.  :-)

-Shay

On Sun, Jan 8, 2023 at 5:13 PM Joseph Mack NA3T via TriLUG
<trilug at trilug.org> wrote:
>
> My UPS started beeping, so I replaced the batteries. There were two banks
> of 4 12V7AH SLAs. The banks were
>
> o 4 Duracells from Batteries Plus
>
> o 4 PowerStars (presumably some generic brand) from Amazon. (about 25%
> cheaper than the Duracells)
>
> The PowerStars were hot and the plastic cases bulged out and had melted
> together (all four coming out of the UPS as one block), but miraculously
> weren't leaking.
>
> One of the Duracells leaked and badly corroded the contacting F2 lug.
>
> I don't give either brand good marks here.
>
> I assume the PowerStars failed first, but the circuitry which detects a
> failed battery gave a pass, as the Duracells were still accepting charge.
> Presumably the PowerStars then got beaten to death, getting hot, till the
> Duracells failed and the circuitry declared the batteries dead.
>
> I assume if the batteries has been from the same manufacturer, they would
> have all failed about the same time and the batteries wouldn't have got
> hot.
>
> Joe
>
> --
> Joseph Mack NA3T EME(B,D), FM05lw North Carolina
> Don't upgrade a working machine - it won't work any
> better - it could work worse; it may not work at all.
> Homepage http://www.austintek.com/ It's GNU/Linux!
>
> --
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