Charlie Young wrote in a message to Roy J. Tellason:
> 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.
 CY> You can connect a big battery to a little UPS and run it for 
 CY> many hours, but you have to limit your power draw to 1/4 to 1/3 
 CY> of the rated power. The UPS can supply full power for 10 to 20 
 CY> minutes, or 1/4 power almost indefinitely.  
Interesting.  This particular unit being a model "520ES",  I would assume 
that the output is rated at 520 watts (or maybe 520 VA?).  I'm currently 
running only this computer,  which has a 230W power supply in it (but isn't 
loaded down all that much),  a modem,  and this monitor off it.  Hmm...
 CY> During a power failure, you can also connect a 12V inverter to 
 CY> your battery if you need more power than 1/4 UPS power. When 
 CY> the power comes back on you might want to disconnect your big 
 CY> battery and charge it with a 2 to 8 amp charger.  The UPS will 
 CY> eventually charge a big battery, but it might take a week or 
 CY> so. 
That shouldn't be a problem here,  as except for the occasional short glitch, 
when we lose power,  it's typically for a matter of a few hours at most,  and 
then they fix it.  I don't recall ever being without power for more than a 
minute or so more than once in a week or longer...
I'll have to look at the loading here and see if it looks like it'll fit into 
that 1/4 - 1/3 rating...
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