On 02/05/2009 05:39 PM, (PeteCresswell) sent:
Per 1PW:
In a previous life, I oversaw many systems with UPS protection.

Here's a question that's been in the back of my mind since I
found out that my APC unit uses a proprietary battery: How about
a UPS that uses a plain old non/vented automobile battery?

- Definitely non-proprietary.

- Probably has a lot more capacity than most consumer-level UPS's

- Quickly replaceable

- Probably cheaper, since it's a commodity

??

Hello Pete:

We never had to try something like that. We only needed something to
absorb sudden dips and spikes. Our UPS systems just needed to last long
enough for our banks of big diesel driven generators to start, stabilize
and switch in.

However, your question is excellent. The problem lies in the design
differences of the batteries.

Typical thin plate automotive batteries will not withstand many deep
discharge cycles.

I believe the old adage that an automotive battery looses one year's
life for each deep discharge, is still mostly true. I believe that
sulphate damage begins with the very first deep discharge and would
accumulate with each additional deep discharge.

Industrial grade Sealed Lead Acid (SLA) batteries are constructed to
withstand these cycles with extra thick plates. This is not to say that
an automotive battery couldn't be used in a rare emergency, but to see
continued use would call for the proper industrial deep cycle type battery.

Someone may post a follow-up in this thread regarding the unmodified
UPS, sensing the automotive battery's soon dwindling voltage as an
unanticipated/early battery discharge.

I suppose you could look into using true/real marine/RV batteries, and
possibly modifying your UPS. However, UPS manufacturers are usually not
very forthcoming with their product's maintenance manuals, schematics,
piece parts, etc.

I encourage you to Google this for a deeper understanding.

My warm regards to you.

Pete
--
1PW @?6A62?FEH9E=6o2@=]4@ [r4o7t]