More info is needed for debugging:
Current at WOT (wide open throttle)
Same for RPM and battery voltage drop
Motor velocity konstant Kv (expressed in rpm/volt, it has a massive effect, cubed, on current and power drawn)

Note that Kv says nothing about max.continuous power, the motor in your toothbrush and the the motors in a 1:1 train can have same Kv.

With the above info you can try
www.rcgroups.com/electric-power-systems-13

Prettig weekend Ron
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