Charging or discharging a battry harms the battry. That’s why thay have life span. The thing is how much is reasonable. If you can take 2 motors at -60 battry amp and stay on the board your doing a lot better than me I’d be in the bush 5m in front of it.
On a street board with urethan I have -35 per motor (-45 per single drive is max for me any higher and the wheels just skid for me) I see up to battry at -20 amps Reguarly and that’s only for a few seconds.
On a very basi level
To see max battry - = max motor amp- you need to be applying full brakes at max duty cycle With out slowing down. By braking you reducing the duty cycle by slowing down.
During regen the battry needs to see a higher voltage coming back than it has as the time so the vesc steps the voltage up to match
You need to think of it in watts see how thay match below.
Motor sees
Full speed 40v at 40A is 1600W
3/4 speed 30V at 40A is 1200W
1/2 speed 20v at 40A is 800W
1/4 speed 10V at 40A is 400W
Battry sees
Full speed 40V at 40A 1600W
3/4 speed 40V at 30A is 1200W
1/2 speed 40V at 20A 800W
1/4 speed 40V at 10A 400W
Now let’s say the motor amp max is now 80A the battry regen max is 40A (total of 1600W cap)
Motor sees
Full speed 40v at 40A is 1600W
3/4 speed 30V at 53.3 is 1600W
1/2 speed 20v at 80A is 1600W
1/4 speed 10V at 80A is 800W
Battry sees
Full speed 40V at 40A 1600W
3/4 speed 40V at 40A 1600W
1/2 speed 40V at 40A 1600W
1/4 speed 40V at 20A 800W
Now let’s say your been less stupid and not slamming full brakes on from full speed because you don’t want to be superman flying off the board and use use 3/4 the brakes On the remote
Motor sees
Full speed 40v at 40A is 1600W
3/4 speed 30V at 53.3 is 1600W
1/2 speed 20v at 60A is 1200W
1/4 speed 10V at 60A is 600W
Battry sees
Full speed 40V at 40A 1600W
3/4 speed 40V at 40A 1600W
1/2 speed 40V at 30A 1200W
1/4 speed 40V at 20A 800W
Hopefully you see most of the time having a higher motor max than battry max doesn’t affect us much due to the duty cycle that needs to be taken in to consideration and why it’s often said you only lose a little top end braking that has little practical use.
The other argument is how long dose it take to get from full speed to 1/2 duty cycle most of us it takes seconds a battry can happily take few 100amps for a few seconds with hardly any noticeable detrimental affect. The max charge rating on battery’s is ther fast continues full charge 4-6amp per cell. For this reason some say don’t set a max battry regen because we only applying that high amp age charge for a few seconds at a time in normal use
