Trying to be budget conscious I recalled that my office UPS (APC) is 1500VA and 865W, and has lead acid batteries inside. It claims 2 hours of runtime at 50W. I got it on sale for $120 or so.
So, I pulled out the Kill-A-Watt and plugged it inline with my laptop, and got a 42W load mostly idle (10% CPU). So, I pegged the CPU's with a tight loop and ran some disk activity and it jumped to 65W. Now, and this was surprising to me, I pulled out the battery while the CPU was at 100%, and it fell to 40W. This battery is supposedly fully-charged. I put it back in and it went back up to 65W. I'm very surprised it's constantly using 25W of power to keep the battery topped off. That's not very green. So, to the original point of demo'ing linux in the field without AC, this is likely to be a cost-effective option (must cut speaker wire! ... use NUT). Among the membership it ought to be possible to borrow a few UPS's for a demo day, should that be necessary. I'm curious how noisy of an inverter APC puts in those things. I'd hope it's better than the one that plugs into my cigarette lighter socket in the car, but I don't have a scope to measure it (I know it's not pure-sine). I'll plug my microphone into it and the sound should give me a pretty good idea. I'm also now curious about using a bigger battery with the COTS UPS since they've already done most of the work for me. I realize the inverter is electrically inefficient, however assuming hot-rodding a UPS can work, bigger batteries are more economically efficient than any of the other solutions I've found, in a $/VA calculation, and they get pretty good runtimes out of relatively small batteries, so they've done most of the hard engineering work I'd be unlikely to replicate. -Bill ----- Bill McGonigle, Owner Work: 603.448.4440 BFC Computing, LLC Home: 603.448.1668 [EMAIL PROTECTED] Cell: 603.252.2606 http://www.bfccomputing.com/ Page: 603.442.1833 Blog: http://blog.bfccomputing.com/ VCard: http://bfccomputing.com/vcard/bill.vcf _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
