Re: Backup power supply

On Thu, 14 Mar 2024 21:00:49 +1300
nospam.Vincent.Coen@f1.n250.z2.fidonet.org (Vincent Coen) wrote:

Assuming it is fully charged which would be normal (assuming no outage in
the preceding 2 - 3 hours 95% or better.
 
Otherwise do you mean the estimated run time if so then system under
power in watts per
hour

You have units confusion. Watt is a unit of power, a rate of
movement of energy. Watt-Hours and similar units are units of energy. Watts
per hour is meaningless.

under the rated size - 25%  so lets say :

Assuming you are talking about an APC SMT750I or similar they are
rated for a power output of 750VA or 500W. At full power the battery is
good for about five minutes.

750 w
----  = 150 = long time :)
5 w

Make that 5 minutes * 500W/5W or 500 minutes which is indeed a long
time but a lot shorter than the 150 hours you were expecting.

Also e.g., my desktop / server system with an estimated consumption of
250w (and it is lower as using modular PSU, 85% eff or better )  would be
around 3 hours but that assumes there is nothing else under load and

No it would be maybe 15 minutes.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
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