MH>TW> All of them I know about use sealed Lead Acid Batteries.
MH>TW> They are "Float" type Batteries and they do not tolerate deep
MH>TW> discharges very well so if you run them all the way down too many times
MH>TW> they need to be replaced.

MH>True.  I have an extra UPS that I'm not using at the moment, but I leave it
MH>plugged in and charged all the time.

MH>If you leave them off for long periods of time, they will end up not working
MH>anymore.  We have had "spare" UPS batteries sitting in our
computer room at
MH>work sometimes for up to 2 years.  When you go to use them, they almost neve
MH>work after sitting that long with no charge.

MH>- Mark

That reminds me of whan i worked in hte engineering Department of the
Local VA Medical center. We topped off any spare batteries on the
charger every three months. And any Batteries in use in Critical Patient
care devices was Test Discharged and Recharged every three months
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 þ SLMR 2.1a þ 0