Darnc73 said:
The BMS is 50amp and I disconnected the discharge as it was cutting out battery at 72v and wouldn't come back on until I charged it. Now it has a little more torque and no issues but BMS is still connected for charging. The battery is 20s/12p and from what I can see the Samsung 35E cells are 5 amp continuous 8amp max discharge. Cheers.
What does "disconnected the discharge" mean?
If you mean that you bypassed the BMS's ability to shut off the output to protect the pack when there are problems, by connecting directly to the cells, then that's a bad idea when it's cutting out like that. (If you want the BMS's protection against overdischarge and unbalanced cells, it's also a bad idea because it can't protect them if it's discharge port is bypassed).
If it was shutting off at 72v, it means it was likely detecting a problem with a cell or cell group, usually one that has a bad cell or cells, or an interconnect issue that's decreased that group's capacity and capability, so it's likely overstressing that group (or groups), and making the root problem worse, just masking it.
It could just be that below 72v the cells and/or the BMS can't handle the current you were drawing, in which case you need either a better BMS (but not one that exceeds the cells' capabilities), or better cells.
If you mean something else, be very specific and we can help you find the problem and fix it.
Either way, if the BMS is 50 amp, then that's the limit your controller can pull from the pack, regardless of what the cells can do.
The cells aren't made to handle what you want out of it either, so at this point you should probably either replace the pack entirely, or buy a second one to keep in parallel with it while riding, so you don't overload the pack and damage it (which has the potential to cause a fire, as unlikely as that is it's still possible, especially if you bypass the BMS's protection).