Originally Posted by
mpetry912
I get the part about the internal shorting of an individual cell.
OK, if that's true, then let's consider a battery that is fully charged - to say 48v, 100%.
Now you ride it and get it down to 50 % remaining. The voltage is something less than 48 volts. With me so far ?
So new explain why, even at 50 % indicated battery capacty - or 25% for that matter - the bike is really no slower than it was at 100%
if the current draw from the battery does not change with regard to voltage, then you have either violated ohm's law or the laws of physics.
explain !
/markp
My comment was directed toward what the individual cells can do. The voltage and current the cell is capable of putting out depends on the state of the cell itself. Any downstream electronics won't change that.
To answer your question, the motor controller sits downstream of the battery. If controls the current applied to the motor. It is only going to allow a certain amount of current into the motor. If the battery has excess capacity, then you may not see a drop in performance with the state of charge. When the battery gets weak enough that it can no longer supply the desired current flow, you will see a drop in performance.
FWIW I feel a drastic difference in performance when charged to full volts vs. even 80 or 90% charge. I have a 50 amp battery while the controller on my bafang limits the motor current to 30 amps. So if the current stays constant, the power into the motor drops as the battery voltage decreases. Your bike has more limiters, it is my understanding that bikes such as yours are limited to some power level. My guess, and it is only a guess, is the motor controller varies the current limit with battery voltage to keep the power in the same. Since your bike almost certainly isn't allowing 1800 watts into the motor, you will need to really discharge the battery to a low state before you will see any drop off in performance.