On Tue, 06 Feb 2007 09:07:37 -0800, Larry Blanchard
wrote:

Dick wrote:

Brief interruptions are problem the UPS can handle.**If*you*anticipate
outages of longer duration, then other solutions must be used.



I agree. The problem was that the packaging/advertising doesn't mention this.
Just a watthour or amphour figure. That's the way they're rated. So I
expected mine to last for a longer period if the drain was low. I was wrong.

If you can use more accurate prediction of how long your UPS will
carry your tank load, buy a UPS by OPTI/UPS. It comes with management
software that will test your actual load and provide an estimate of
how long it can carry the actual load. In a test situation you could
turn the heater thermostat so the heater is on during the test. OPTI
has some large capacity UPS models.