Capacity Testing and 20 HR Rating
I'm thinking about doing a capacity test on my four GC2's. They have a 20hr rating of 215Ah. One thing I'm curious about is how the 20hr rating would have been determined. Being 6v, would they h...
Forum Discussion
pnichols wrote:BFL13 wrote:
...20 amp draw was twice the 20 hr rate, so the capacity at that high rate would be much less than 200AH if you had run it to 10.5v
I do have a 120 V AC personal heater that I could have used to load the 200 AH AGM battery bank with around 10 amps, but I didn't want to take that many hours for the capacity test.
Are you saying that my test gave an artificially high indication of capacity left because I drew high current over less hours instead of low current over long hours?
If so ... boy ya can't win at this game and I guess I'll have to step back in ancient times by putting on some old trousers, drilling a hole in the tops of the batteries, and then try to suck up enough acid to float that colorful little glass tube inside a hydrometer. :B
P.S. I was just kidding in the sentence above, so please don't you AGM battery owners drill any holes in them!
Phil, I don't know what your test showed for what the capacity is on your batts at their 20 hr rate. The Peukert reduction in capacity by using a higher rate isn't so bad when you don't run the higher rate for very long, as I found when running a test on that some years ago, but it does screw things up in some way even so AFAIK.
Your test did show the batteries still work quite well though.
