> I'd like to get a setup going here which would do that.  I thought about
> adding more capacity to this UPS I have here,  but asking them at the
> factory about it they nixed the idea,  told me it'd burn up the inverter.
> They said "some" of their models would deal with more battery,  but it'd
> cost me maybe $1000 to find out.  I don't think I'm gonna do that,
> though...   
 
More battery hooked in parallel isn't going to change a stinking
thing except how long the load (computer, monitor, whatever) will
work. The extra batteries can't supply more voltage than the
computer is designed to handle and they won't supply more amps than
the computer is capable of handling except in the case where the
UPS might short out. You'd get some real fire going that way and
each bank should have a fuse in it which is rated at the max
current that the computer can handle so that does not happen.
The only real problem that would occur by using extra batteries
would come if you had a power outage that lasted for more than
about 8 hours (guestimated.) Then you are going to be looking at
an extremely long recharge time which might be unacceptable.
In the event of an extended power outage, I would want to cut
the external batteries out of the circuit when the power comes
back on and recharge by other means. Since I am looking at
recharging 8 12 volt batteries (8 6v in series equals 4 12 volts
in series) in series (with 4 12 volt batteries in series) that
gives me an effective total of 8 12 volt batteries in series.
Since thats about 2 batteries short, I would simply add two more
12 volters in series with those and rig up one of my homebrew
battery chargers to the whole mess and plug them into the wall
and let them charge for about 10 to 18 hours if necessary. Then
they would be ready to go for the next emergency.
 
Don't see any way for any problems to develop that way. I have been
doing it that way for a couple of years now with never a problem
of any kind.
 
Bill Bauer
--- DB 1.58/004358
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