Hey guys, I've got a problem to solve.
I'm currently turning a small and very old uncontrolled boat with a little outboard motor (not really, the electric motor is in the boat's stern and drives the outboard motor through a complicated set of gears which I'd like to get rid of) into a little RC boat with a BETTER little outboard motor which has the motor where the engine would sit on the real thing and thus a whole lot less gears.
The problem is that the motor of that thing is rated for 3 Volts (which, on the other hand, does come in handy for keeping the 2 C-size batteries in the bow as a power source) and I so far I couldn't find an ESC for that thing.
Now I had the idea of taking the control board out of a standard size servo (whose motor was only slightly smaller than that of the outboard motor) and simply leaving the potentiometer as a way to adjust the "neutral" or "off" position.
As we all know said potentiometer usually tells the servo the orientation of the servo arm and makes it run one way or the other until the servo arm reaches the position it was told to assume by the incoming PWM-signal, so my thought was that since the motor would just continue to run if the poti didn't change, and its speed proportional to the user's stick / trigger / wheel input no less, I could simply connect the whole thing to the throttle slot of the receiver and solder the outboard motor to the outputs.
And it does indeed work quite well, apart from these 2 problems:
1. The "dead zone" is extremely slim and seems to shift with every input, sometimes resulting in the motor suddenly going backwards at slow speed instead of stopping when I returned the input to neutral, despite the poti not being moved one bit.
2. When I dip the prop into some water in my sink and let it stirr it around I can throttle up until at some point the motor slows down again instead of accelerating any further, even tho I try to keep the water resistance low by holding the motor parallel and close to one side of the sink so that the water runs in a circle. My guess is that holding the motor in a fixed position causes a bigger water resistance than if it was driving the freely movable boat instead, but I also think the electronics may not be suitable for sustained running periods of the motor.
Can anyone point me at my mistake if I made one?
Or maybe u know where I can get an ESC that can run on 3 Volts and can run motors that only need like 0.7 amps (the readings on my amp-meter were pretty erratic, which may have been caused by the huge range jump from 200 mA to 10 A (200 mA didn't seem to be enough, but 10 A was too much to measure the current accurately I think).