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Hi folks,
I am new to this forum, but not new to EV's. I have had an EV on the road for over two years now and I wanted to pass on some calculation I have done on FLA batteries. I often see discussions that FLA batteries will last much longer if they are not discharged very much. However, my calculations suggest that overall the longevity is not reduced very much in terms of total miles driven on a battery pack.
The US batteries web site has information on the number cycles vs. DOD for their batteries. They show that at 20% DOD their batteries are good for 3300 cycles and at 50% DOD they are good for 1150 cycles. That may initially seem as a big difference, but overall the amount of energy cycled through the batteries is not that different (only 13% less energy cycled at 50% DOD - this means only 13% fewer miles overall).
Here are the calculations I have made (for simplicity let us just do the calculation for one 6volt golf cart battery of 230 Amp hrs).
At 20% DOD the battery will have put out 276 Watts
At 50% DOD the battery will have put out 690 watts
276 Watts for 3300 discharges = 910 Kilowatts over the life of the battery
690 Watts for 1150 discharges = 794 KW
So the actual difference between the two discharge rates over the life ofo the battery is only 13%.
I am new to this forum, but not new to EV's. I have had an EV on the road for over two years now and I wanted to pass on some calculation I have done on FLA batteries. I often see discussions that FLA batteries will last much longer if they are not discharged very much. However, my calculations suggest that overall the longevity is not reduced very much in terms of total miles driven on a battery pack.
The US batteries web site has information on the number cycles vs. DOD for their batteries. They show that at 20% DOD their batteries are good for 3300 cycles and at 50% DOD they are good for 1150 cycles. That may initially seem as a big difference, but overall the amount of energy cycled through the batteries is not that different (only 13% less energy cycled at 50% DOD - this means only 13% fewer miles overall).
Here are the calculations I have made (for simplicity let us just do the calculation for one 6volt golf cart battery of 230 Amp hrs).
At 20% DOD the battery will have put out 276 Watts
At 50% DOD the battery will have put out 690 watts
276 Watts for 3300 discharges = 910 Kilowatts over the life of the battery
690 Watts for 1150 discharges = 794 KW
So the actual difference between the two discharge rates over the life ofo the battery is only 13%.