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Don; I totally agree with your last statements about “misleading Ah claims” Here is a formula I got from Peter F which is really close to the “usable” range on
my 65 Datsun. >> (Total pack voltage X AH rating of each battery) = watt-hours (whr) stored >> whr stored X 0.57 (adjustment for Peukert effect) X 0.80 (useable DOD for >> floodies or Gels) = usable whr >> useable whr divided by watt-hours per mile used.
My 65 Datsun has (13), 12 volt, 65Ah Odyssey AGM batteries. It averages
~ 275 Whr’s per mile (13) Batteries * 12.65V * 65Ah = 10,689 Whr’s. 10,689 Whr’s * 0.57 * .80 = 4,874 “usable” Whr’s. 4,874 / 275 Whr’s per mile = 17.7 miles. This is right on the money for my usable range. Not sure how this works for tractors, but it’s really close for my
electric vehicle. I’ve been told that you don’t even have to consider the Peukert effect
for the Lithums, but there is some loss of range due to cold weather. Thanks; Dennis
What is misleading with lead is the AH claims by manufacturers. 200 amp hours at a 5 amp load
is just not how most people use batteries. With significant loads your 200AH rated lead is really closer to 100AH. If you expect to get close to the claimed cycle life with lead your use should be 50% of that. So 50AH of capacity DOD would be your best chance
at maximum success. You could do about the same thing with a CALB 60AH cell. Your cost would be reduced by 40% of
the 100AH cells and it is highly likely to still way out last the lead pack. What is the amp load and for how long? Don Blazer |