Motor dieing off when throttle is give on low battery

Erikxbg

New Member
Hi there! Basically when I give too much throttle or the battery is too low the system shuts down and I need to reconnect the battery to fix it
I have a 14s 2p mj1 cells (10a 3.5ah) and 42v 1500w
The problem mostly occurs under 52v
Thanks in advance
 

PDXzap

Well-Known Member
I'm not Court but your problem has all the symptoms of a battery that's getting old, has a bad cell/cells, or possibly was under specced. It could also point to a bad BMS (Battery Management System) in the battery.
When pulling too much current this can drop the voltage causing voltage sag and your BMS is shutting the battery down to keep the battery from being severely discharged. Removing and reconnecting the battery gives the battery enough time for the voltage to build back up i.e. the bad cells can get recharged by the good cells and the BMS once again senses a proper voltage.
Just my theory.
 

harryS

Well-Known Member
Under spec. The cells in his battery max out at 10A, and with only 2P, that's 2 cells in parallel, he gets 20A. That's enough for a lot of bikes, but 1500watts at 48 volts will require over 30 amps.

In addition, pulling the maximum rated amps out of the cells will shorten the life. I would suggest a 14S-4P or 14S-5P.
 

Court

Administrator
Staff member
Thanks so much @PDXzap and @harryS, great answers! Sorry I'e been a bit offline and unable to respond as quickly or thoroughly as I'd like. You guys are heroes :D