On Thu, Apr 14, 2011 at 6:06 PM, Bill Campbell <centos at celestial.com> wrote: > We lose power fairly frequently here, and need the UPSs to keep > things going long enough to get generator backup started. I have > found that the APC UPSs really don't like cheap generators. We > had a week long power outage after the 2001 Clinton Inaugural > windstorm, and I got an inexpensive generator from Sears which > didn't work at all with APC equipment. Cheap generators are just that - cheap. If you look at the output on a 'scope then you'll never want one anywhere near anything delicate. Your UPS is probably manfully trying to smooth out the spikes and if it's really clever trying to correct the frequency of the AC. All that gets soaked up by the batteries and it knackers them in no time. For regular outages it's far better to store DC instead of doing the full AC - DC - AC - DC cycle. Shame that there isn't a good way of doing that with standard computer equipment.