In article ,
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.

I have not done this but your expectation sounds reasonable.

Many UPS units produce a trapezoid shape output but again I do not see a
problem plugging one UPS into another.

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Telamon
Ventura, California