This might be informative to anyone with an electric Kayak or anyone who uses electric motors to power your boat. It's been talked about here in other threads, usually in relation to Kayaks.
Last fall I installed a Pulse Width modulator on my two motor, minn kota 35 lb/thrust, electric catamaran. Homemade of course. (see lower thumbnail) I originally had one motor connected directly to 12 volts. The second used the 5 speed controller that came on the motor that I relocated to a console. The controllers have limited lifespan located outside of the motor for some reason. I had gone through two of them.
The Pule Width Modulator is an electronic device that is basically a motor variable speed control. As I understand it, it sends rapid pulses to control the speed that is very efficient. For the first time I've put about 6 hours on it this spring and I must say, that if it holds up I'm impressed. And the thing is available on amazon or ebay for about 17 bucks. Many of them have a reversing switch wired in. Wiring and incidentals add another $5. And it's simple. Two wires connect from the battery and two connect to the motor. Screw down connectors marked motor + and -, and battery + and -.
The variable resistor is smooth and very linear. i.e. it goes from 0 to max with a smoothly variable speed increase.
Comparing it with my other motor which is turned on full with a switch or off, no in between. I'd say the PWM produces about 90% of the thrust of the direct connection. I expected that. The nature of the unit and the way it works should give about 10% longer battery life though from what I've read.
This is the one I got. They come in many varieties. Look up 'pulse width modulator' on amazon. I chose this one even though I had to add my own DPDT reverse switch because it was 60 amps. Many of the others are 30-50.
