Swe wrote: ↑
Dec 30, 2017 3:37 pm
How do I know my battery supports regen? Is it depending of what BMS is used? I have a battery a few years old from BMSBattery "bottle-09". I have not opened it up to look at the BMS but according to the link below this is the BMS that I have. It has a charge and discharge port. And with regen how to know if it supports charging through discharge port?
Depends on the design.
Most common way to implement separate charge and discharge protections is with a single FET on each, each blocking the appropriate direction. If this is the case then the discharge port can carry as much charge current as discharge current but you will have no overcharge protection. In other words, it will work just fine as long as your controller does a good job regulating regen voltage. If it fails and you see an overvoltage AND the battery is near full you could see damage or a fire.
Note that even if you set regen to "off" you can still see regen if you exceed the base speed of the motor (i.e. you are going down a hill.) In that case you will be feeding back through the discharge port and there's not much you can do about it; the diodes in the controller FETs will conduct and feed back voltage.
If the discharge output has two back-to-back (NOT parallel) FETs then it will likely protect against overcharge there as well, in which case no worries.