Quote:
Originally Posted by onewheelcop
I was just going by simple math. May not be 100% correct, but it has to be in the ball park.
6 8volt T875's have 1020AH, and 8 6volt T105's have 1800AH. If you divide 1020AH by 20ish miles= 51AH per mile.
1800AH divided by the same 51AH per mile=35 miles.
going from 20 miles to 35 miles is way more than 32% increase. roughly 75% increase
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First, learn how to calculate the AH of a 48V battery pack. (Volts add in series, AH stay the same.)
Not quite sure where you get the 20 mile range figure for the 6x8V T-875 batteries. Have you ever ran a T-875 pack in that specific cart?
You're also assuming you can get 100% of the stored energy out of lead acid batteries without irreversibly damaging them. Trojan, and some other deep cycle battery manufactures, say you can do 80% discharges (20% SoC - State of Charge), but they sell batteries and the lower the average SoC maintained, the shorter the cradle to grave lifespan of the batteries, so most electric cart owners try not to discharge their expensive battery pack lower than 50%.
Measuring the At-Rest voltage before and after driving measured distances over mixed terrain, with different amounts of aggressiveness, my cart gets from 3.3AH/Mi to 5.6AH/Mi, the average AH/Mi being slightly higher at 42V than it was at 36V over the same course. The tests include a both stock controller and an Alltrax DCX400 running at 36V with stock PDS motor.
If you want a fairly accurate guesstimate as to how much the range difference is between a T-875 48V pack and a T-105 48V pack you at the differences in the runtime published by Trojan for their T-105 and T-875 batteries with the same discharge rate. Unfortunately, Trojan does not publish the capacity minutes for the 56A and 75A discharge rates, which is
average amp draw range for most relatively stock carts, so we have to go with the 25A rate
T-105 = 447
T-875 = 295
447 - 295 = 152
152/295 = .5152542 = 52%
IF, and that is a big if, the cart will get 20 miles with a T-875 pack, it will get (mathematically) 30.3 miles with the T-105 pack. It will be less than that due to the Amp draw averaging upwards of three times the rate that was used for comparison and the Peukert factor and peaking at ten time or more that amount.
FWIW: The increased range going from a 225AH 36V pack to a 245AH 42V pack tracked the increase in kWh stored fairly well, but the 225AH 36V pack was not the picture of health, so it may have been less.