> Keep in mind that the batteries are not the only thing on small cheap > Domestic UPS's that are rated for minutes. Same goes with their > electronics, Heatsink etc.
If you are interested in times measured in hours, you will be running a typical small UPS at well below full load. For example, if full load is 5 minutes, 2 hours will be 5%. That's assuming time*load is linear. From what I've lower loads load are more efficient. For example: Typical Backup Time at Half Load 15.9 minutes (250 Watts) Typical Backup Time at Full Load 4.6 minutes (500 Watts) That's for an APC SUA750 from: http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA75 0&total_watts=50 Somebody pointed out that low loads are inefficient. That doesn't match the numbers I'm seeing, Maybe I'm not looking at low enough loads. From their chart: Watts * minutes 50 * 103 = 5150 100 * 50 = 5000 250 * 15.9 = 3975 500 * 4.6 = 2300 I wonder where the knee is. 20w? 10w? That's also from the data sheet rather than measured. It probably assumes a new battery. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
