

| Subject: | Re: Battery Demand Calculator |
| From: | neil n |
| Date: | Sat, 10 Jul 2010 09:49:14 -0700 |
On Sat, Jul 10, 2010 at 8:15 AM, Mike "Rocket J Squirrel" <camping.elliott@gmail.com> wrote: > Neil was asking an Ohm's Law questions about calculating appliance current > draw. > > Herewith, formerly on the old wiki, then lost, and now placed back on the > wiki for all to use, is the handy Battery Demand Calculator: > > <http://www.vanagonwiki.net/wiki/Living_Off_The_Grid_Articles> > > Written for the fine folks in the VW Vanagon Westfalia community, > but useful wherever fine living from lead-acid batteries is found. > > -- > Rocky J Squirrel > > > > > neil n wrote: >> >> Hi all. >> >> Viewing this: �http://tinyurl.com/23utmeo in the store, I wondered how >> many amps it would use. On the back it says: 12 Watts, 12 Volts. Only >> vaguely recalled Ohm's Law at that moment, didn't obviously know the >> resistance of the unit, so couldn't calculate amps used. Bought it >> anyway. >> >> At home checked current draw. Low - �0.45 amps. High - 0.6x amps >> >> But entering 12 volts and 12 watts here, >> http://www.the12volt.com/ohm/page2.asp shows 1 Amp. Here: >> http://www.csgnetwork.com/ohmslaw2.html �0.58 amps. hey neat. Thanks for posting that Mr. Mike. I found it interesting to compare the same wattage appliance on 12 volt and inverter operation. Though as the page say's, "measure, measure, measure", the amps drawn are more than double on inverter operation. This is something I was already aware of, and it has been pointed out in the past (inverter inefficiency), but great to get a ball park comparison. Neil. -- Neil Nicholson '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/ http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
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