On Sat, 10 Mar 2007 16:50:58 GMT, Ron Hardin
wrote:

Brenda Ann wrote:
You're not going to extend your runtime near as much as you might think. If
you had an UPS with a clean enough pseudo-sine waveform to even get the next
one in line to power up stably (and you have to get into some very very good
ones to do that, they basically have to be generator rated), then you have
to deal with the issue of the other UPS'es in the chain not being 100%
efficient, so you lose a lot of what you would have gotten from that first
unit in the line. This of course follows up the chain.

Doesn't the UPS just pass along the input to the output as long as it's ok power?
So I don't see the loss. The second UPS just passes along the output of the
first UPS.

That's more of a battery backup than a real UPS.