Meat Plow writes:

On Tue, 08 Dec 2009 23:32:19 +1100, Sylvia Else
wrote:

Meat Plow wrote:
It was purchased around 2004
and last time I tested it in Oct it ran for an hour unplugged.

That's a long time for a UPS, and suggest's it's not heavily loaded. The
self test would be similarly undemanding.


The 350va powers a cable modem, two USB hard drives and a Linksys
network storage server 24/7/365.

The self test on the two 1000va units simulate a power failure
allowing them to run off battery power for 10 seconds or so. Enough
time for the unit to evaluate the state of the batteries according to
how it was designed. One 1000va unit provides power for a SA Explorer
HDTV cable DVR and a Panasonic 51" rear projector TV. The other
powers a 3 yr old desktop PC and 22" monitor and a 32" LCD HDTV.

I don't think you understand the principals of demand or load well
enough.

My APC SmartUPS 700 successfully ran selftests up until one of the
batteries failed and everything it supplied went down. :-(

It runs with a maximum load of 30%.

I have been contemplating using two full size 60Ah car batteries
externally instead of the small 7Ah internals.