Ebike going up a hill controller and motor gets hot causing a circuit break Motor: satellite down gearing, 350 watts, rated @36 volts.
Pack: 40.2 volt 10 series by 7 parallel.
Lately the last 3 times I go up steep hill the battery wires, controller, and motor are hot to the touch, not burning but very warm and a heat sensor kills the power. As I sit half way up a hill waiting for it to cool off I have to disconnect the battery for it to reset. I always assist the uphill climb by pedaling as much as I can on seat not standing. I often check for the correct tire pressure. And my ebike is 100% throttle controlled but it's not easy modulating a throttle when you're pedaling vigorously.
This has only been occurring since I fixed my battery pack by replacing a defective parallel row 18650 batteries in my 70 battery pack. Since I fixed the pack my ebike has never been so torquey. I get the same top speed but it really throws you back when you floor it from zero like never before. The main reason I got this ebike was mainly due to living at the top of a hill.
I can't figure out what would be the best solution to fix this problem.
Any ideas?
As one commenter suggested, the issue is likely not that the voltage is incorrect, as a 36V battery means 10 typical Li-Ion cells in series, which will have a fully charged voltage of 42V.
It is possible that your battery pack had a BMS or some kind of current limiter or fuse system that prevented too much current from being drawn, or that some of the motor controller settings, such as current limiting were changed.
It is also possible that when you modified the battery pack you used a different type of 18650 cell that those originally present in the pack, or used a different type of conductor to add those cells to the pack, which has a different amount of resistance.
To debug I would first suggest using a current and voltage meter to measure the power output and current draw to ensure that your usage is below 350W, and then possibly adjusting the settings on your motor controller.