Regulate a 12V Water Pump with a Motor Speed Controler (PWM)

During our trip to New Zealand, we bought a little Camper Van. For some reason, the built-in water pump had too much power so that the water shot out of the tap and splashed everything around it.

To restrain the pump, one could probably install a resistor. Resistors burn off unused current as heat and therefore are inefficient, which is annoying. But more importantly is the question: How much resistance is needed to slow down the pump to a desired level?

A better alternative is using a motor speed controller based on Pulse-Width-Modulation (PWM). Once a motor gets switched on, it takes a while to reach full speed. The controller uses this fact and turns the motor on and off really quickly to reach the desired speed. This way is possible to control the speed of a motor from 0 to 100 %, which makes it easy to find the ideal configuration. Such controllers can also be used as LED dimmers, which is great because after the time in our Van I can give the not-so-cheap device a new purpose!

Such a motor speed controller is the solution I settled on for slowing down the water pump in our van. And I must say it worked out really well!

The installation looks a bit messy. But hey, it just for a year (and it was messy before).

~ 2024-11-01