> Help this stranger to your US terminolgy- are the trolling batteries 
 > gel type or liquid type? Lead- acid type ie 2v per cell?
Trolling batteries are automotive-package deep cycle batteries, meant for use 
with a recreational vehicle, running an electric trolling motor for fishing, 
etc. They're liquid lead-acid.
 > On what basis do you decide to retire an aged battery? If you 
When it won't run the UPS for any length of time. I always attempt to charge 
it with my regular battery charger first. This last time, I fooled around for 
several days and couldn't get the one battery to hold over 8 volts under 
ad.
 > Highly- regulated *should* mean, that the output is exactly matched 
 > to the needs of the battery ie fast recovery when flat. It seems though 
Highly regulated means that the voltage is closely controlled to hold the 
battery in a "ready" condition. The normal duty cycle of a computer UPS is to 
sit there for weeks, then hold the power for long enough to do an orderly 
shutdown or keep things running through a short outage. There is no need for 
fast recovery, as that's not the usual method of operation. Even my 100AH 
batteries could be charged in 3 or 4 days from near-dead at the 1-amp rate of 
the UPS's charging circuit.
[[regarding equalizing the cells with a 5-amp charge rate:]]
 > That's better. Is 5 amps enough? Assume that the battery is good for 
Everything I've read says that batteries should be given a periodic 
equalizing charge of between C/10 and C/20, so 5 amps is enough for my 100AH 
batteries. The idea is to get all the cells gassing freely for some time in 
order to be certain that all cells are fully charged.
 > I wonder what a COCO is?  The other three starting batteries you mention 
s
 > having good lifetimes, are well matched to their duty; momentary discharge
 > followed by brief vigorous recharge. Deep discharge [standby power] is 
ery
 > wearing and such batteries are not expected to have long lifetimes.
A COCO is the affectionate term people gave to the old Radio Shack COlor 
COmputer. Mine is connected to a home-made interface box and controls the 
draft on the woodstove that heats my shop. Of course, with nearly 1200 watts 
of computers running all the time, there's much less need for wood heat these 
days. If you're interested in the details, you can obtain STOVE.ARC by 
FidoNet F'Req from 1:234/100 or anonymous ftp from toltbbs.com in the 
directory \PUB\FREQ.
 > you have not used the same batteries as were provided with the UPS then 
he
 > volts- per- cell on standby duty may not now be optimum. Especially if the
 >batts you chucked, were nicads. Important that you keep your chosen 
rolling
 > battery, at the manufacturer's recommended "floating" voltage.  
These batteries are seldom discharged to amount to anything at all. The 
originals were sealed lead-acid type, but may or may not have been gel cells. 
Some of these things that I've fooled with have had what appears to be a 
garden tractor battery with sealed caps. I've removed the caps, added water, 
and sometimes gotten a bit more life from them. I'm floating a pair of 
12-volt batteries in series at 28 volts; that should be high enough to keep 
them fully charged, but not enough to cause excessive water usage. Which is 
the case, I only have to add water 2 or 3 times per year.
 
I'm also beginning to feel that cycling (discharging) the batteries once in a 
while might not hurt them. Perhaps run the UPS for 15 or 20 minutes every now 
and then. Give them an equalizing charge afterwards.
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