Dave,
If you used a resistor, you’d need 0.6 ohms at least 240 watts. Probably not practical. You could put a load on your batteries by turning on most of your lights, cabin fans and other loads. Ron From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of David Knecht via CnC-List Sent: Tuesday, February 7, 2017 11:32 AM To: CnC CnC discussion list Cc: David Knecht Subject: Re: Stus-List Battery test I have been following this discussion and would like to do this for my batteries. Can you suggest what would be an easy/appropriate ~20A load generating device? Dave Aries 1990 C&C 34+ New London, CT cid:image001.png@01D28138.02844420 On Feb 7, 2017, at 10:15 AM, Della Barba, Joe via CnC-List <cnc-list@cnc-list.com> wrote: Easy cheap way. If you have accurate volt and amp meters, a 20 amp (or near enough) load applied for enough time to drain the batteries 50%*. You should see 12.2 for wet cells and 12.3 or so for gel/agm. Light loads like 1-5 amps and heavy loads like 50-100 amps both will be inaccurate because of Peukert’s law. This law deals with the fact that a 100 AH battery can supply 100 amps for 1 hour or 1 amp for 100 hours in theory, but in practice 1 amp will last longer than 100 hours and 100 amps won’t make the full hour. 20 amps is a good value for these tests. * (AH capacity of batteries/load in amps) /2 = time in hours for 50% discharge
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