On Tue, 07 Oct 2008 21:39:02 -0700, Bruce L. Bergman
wrote:

On Tue, 07 Oct 2008 23:42:46 -0400, clare at snyder dot ontario dot
canada wrote:


Get a pair of 7 or 8 ah AGM batteries commonly used in alarm systems,
emergency lighting systems, computer UPS, and other rechargeable
devices. Should cost about 25-30 each - possibly as much as 35
depending where you buy them. Put the pigtail from the old battery on
and GO!

Note that the batteries made for UPS Systems have special codes
added to the standard model numbers, with a higher discharge rate, and
a corresponding higher price cause they cost more to make. And they
have different terminals (usually bolted lugs instead of QC Tabs) that
can pass the higher current levels.


Not true.
I replace at least 50 UPS batteries a year - many different
manufacturers - and they all use either PE12V7.2 or NP4-6 batteries
with 1/4 or 5/16" push-on spade connectors.(or as you call them, QC)
Same batteries as in the emergency exit lamps, the burglar alarm, and
my rechargable spotlight. Same battery in my old cordless weedwacker
too. Same as in my kid's electric scooter, too.
When you get up into the 16AH batteries lugged connectors are more or
less standard (like the ones in my Black and Decker cordless lawn
mower)
Your standard 7AH batteries have a 20A fuse and will see a 6A - 10A
max load for an hour or two - the same size batteries in a UPS might
see 40A to 60A load, but only for three to ten minutes.

A 600 va UPS draws approx 60 amps at full load (Blazer with one
PE12V7.2 battery) An 800 va unit usually runs on 24 volts (2 PE12V7.2
batteries or 4 NP4-6 batteries. so sees a draw of 50 amps The 1000VA
units I service run on 36 volts (6 NP4-6) except the extended run
capable system which runs on 42 volts (7 of the same) and sees about
27 amps draw at full load. Most UPS systems run at less than 1/2
capacity.

For a while we could only get the 1/4" tabs, and we saw a few where
the connections heated up under load. My supplier now stocks the
proper 5/15" (nominal) tabs.

The 24 volt scooter (350 watt) draws approx 15 amps (and runs about
1/2 hour on a full charge, pretty well flat out, or an hour just
tooting around)

About the only other place this would be useful is driving an
electric starter for a small (under 10 HP) gasoline engine, where the
battery size and weight is an issue.

-- Bruce --

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