JH> Yep, and I don't know that I've seen a reply to his question
 JH> about putting a diode in the recharge circuit, which would
 JH> prevent recharge, but what good would that be - to have a UPS
 JH> which couldn't keep its own battery (ies) recharged?

not its batteries... they'll still be on the internal circut... the
externals... to charge them... hummm, and now i just thought about how to
keep the seperate charges from getting out to the others... maybe the relay
idea isn't so bad... i built a bench power supply that uses a relay driven
by 12 vdc off a rectifier to know when to open the drain shorting resistors
i place on the capacitors when power if off... its a rather simple
design... using a wallwart as an external power supply detector should be a
relavtie no brainer... now to locate info on something that can handle the
current thru the contacts... possibly a heavy duty automotive fog lamp
relay?

)\/(ark