Kirkland battery question (amp hours)
Hey everyone! Will be picking up my battery monitor next week and I will have to enter how many amp hours my battery bank holds. I have 2 Kirkland (Costco 6volts ) 2-GCS The only real info on...
Forum Discussion
naturist wrote:Canuck_in_NJ wrote:
Can you teach a man to fish?
Is there a calc to get it from the 75 amps? Is it usually listed with a 25/amp draw?
Love to, but the problem is that there is no calculation to get there from either of those datapoints.
Both the 75 and 25 figures are a function of "wire size" or rather terminal and buss-bar size while amp-hour capacity is a function of plate surface area, thus they are completely independent and unrelated variables.
RC is at 25 amps. EG, a battery with RC of 160 minutes has 66.6AH. (at the 25 amp rate--NOT the 20 hr rate)
(25 x 160 = 4000 amp- min or 66.6 AH)
Golf car batts use 75 amps as their rate, not 25. RC 107 is 133AH at the 75 amp rate. (not the 20 hr rate for AH)
The 75 and 25 are just the "rates" in amps like the 20 hr rate is in amps. Peukert calculation will get the AH to compare the 75 and 25 with the 20 hr rate.
The 20 hr rate for 208AH is 208/20 = 10.4 amps. Naturally the battery will go flat sooner with a 25 amp draw and much sooner with a 75 amp draw.
A 100AH battery has 5 amps as the 20 hr rate. But at 25 amps it will only do 2.7 hours
Going from either RC rate in minutes to AH at the 20 hr rate can be different with different battery brands and types because of different Peukert Factors among batteries.
It is all in this bible:
http://www.bestconverter.com/Books_c_67.html
