I want to build a motor speed controller PCB using an 18650 battery for input power and I need adjustable output 1-12 volts to run 21 volt, 2-4 watt DC brushed motor.
I tried mt3608 boost converter. I was able to adjust voltage to motor and the motor runs but when put a load on it the motor stopped. It doesn't have good torque even when I put voltage up to 18 volts.
In the beginning, the motor runs fine but when battery level go down motor starts running slow.
what can I change or add to PCB so it will provide constant power to motor even when batteries are low and motor just cuts off rather than slowing down?