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 From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Russ & Melody via CnC-List Sent: Tuesday, February 07, 2017 00:41 To: cnc-list@cnc-list.com Cc: Russ & Melody <russ...@telus.net> Subject: Re: Stus-List Battery test Hi Len, If you're 100 percent full and have a coffee in your hand, may I suggest some advice from Bobby... and words I live by. Don't warry. Be Happy. Cheers, Russ Sweet 35 mk-1 At 07:28 PM 06/02/2017, you wrote: I think the CBA would work well so far from the little reading I have done. I have four 6 volt deep cycle batteries for my house bank and a Link monitor. I also have a simple analogue load tester. The problem is the solar panel masks any shortfall in the bank by fully charging usually before I make coffee in the morning. The house bank isn't quite as full on a rainy day and everything works but I would like to know how well. I probably should just leave it alone but if the bank is 100% charged but at 50% amp hour capacity I want to know. Len
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