svmc e-brake/regen brake with 18650 battery pack / agm

[gbruhin]

Hi,

Is regenerative brake recommended/possible with li-ion 18650 battery packs. Just bought a chinese 72v 22ah 3000w 18650 battery pack that has 5a charging port, the seller told be it supports regen. Do cheap BMS usually support regen ?

What current limit should I set if any, 5a ?
What would recommended value be for AGM batteries ?

If I enable e-brake without regen where does the energy go ? does the controller dissipate the heat ?

Best regards

 

[AHicks]

Will be watching with interest, but I don't think the BMS will be in the circuit when considering power from the regen. This power will be back feeding the battery output wires.

Yes, for sure there is stress on the controller (and everything else e.g. motor, battery) when it comes to handling this power.

My understanding is the e-brake and regen are one and the same, and cannot be uncoupled so you get just one or the other.

 

[Trumplestilskin]

I'm interested in this as well.
I have a Sabvoton 72150 which I've configured with variable regenerative braking using a second throttle.
Depending on how hard I apply the regen brake, I've seen as much as 2000 watts going back into my 72 volt battery.
Even though it's typically only for very short bursts, I wonder how healthy this is for my battery. This is way more power being input to the battery than I would ever charge it at.

 

[fechter]

Teslas do it all the time. As long as you aren't running high currents long enough for things to get hot, I don't think it does significant damage. Reducing the depth of discharge each cycle even a little bit has to help the cells.