I have a very similar looking controller:
https://imgur.com/a/Z2u2Zfv
Mine controller is 48v, and I want it to run on my 36v battery. If I have the 36v battery charged to 42 volts it will run until I try to hit a high speed or climb a hill, when it cuts out from the voltage drop.
I tried to do the same thing as you, so first I soldered a in a 3.3k ohm
resistor in parallel with the "2001", but this made the battery cut out way faster (a split second after I hit the throttle, each time). Then I desoldered the "2001" and put in the 3.3k in that spot on it's own. This made it work again, but it cuts out with exactly the same behavior. Maybe mine needs a different value, or my PCB is different enough that it is adjusting the HVC instead of the
LVC, or something? I'm stumped.

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