# Rate of discharge for a battery

## Main Question or Discussion Point

I am designing an electric vehicle and choosing the batteries. For this i want to model some inefficiencys into the batteries. I came across the formulae T=C/I^n where

T=battery life
C = capacitence
I= current
n= Peukert's number

would 1.1 for n be ok for lithium ion, it seems to take quite a lot off with large currents, i couldnt find a general number for li-on only that lead acid use 1.2-1.3.....

Battery = 100 Ah
Voltage motor = 156 v
cell voltage = 3.3v
average current = 36 Amps

the current was calulated from power requirements at any given time P=IV

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mheslep
Gold Member
I am designing an electric vehicle and choosing the batteries. For this i want to model some inefficiencys into the batteries. I came across the formulae T=C/I^n where

T=battery life
C = capacitence
I= current
n= Peukert's number

would 1.1 for n be ok for lithium ion, it seems to take quite a lot off with large currents, i couldnt find a general number for li-on only that lead acid use 1.2-1.3.....

Battery = 100 Ah
Voltage motor = 156 v
cell voltage = 3.3v
average current = 36 Amps

the current was calulated from power requirements at any given time P=IV
C is not capacitance, it is battery capacity. Re n, I don't know but a good Li-ion should be much less than 1.1.

C is not capacitance, it is battery capacity. Re n, I don't know but a good Li-ion should be much less than 1.1.
Actually from reading the wiki on this it looks like the equation is meant for lead acid only, so probaly thats why i cant find a number. I would like to find a general alogorithm just to make things simpler in my spreadsheet!