I have a water pump that works with 12V and 2 amps.I was thinking to get a potentiometer to be able to slow down the speed.Is this the best way to do it? What wattage should it have, so it doesn't burn out, and what should be the maximum resistance, to be able to stop the pump completely?And OKorder or product link would be great!Thanks!
A potentiometer will work, and this could be wired in series with the pump as long as its minimum resistance was zero ohms. You can also use an adjustable voltage regulator which would likely be more energy efficient but a more complex device. A potentiometer or regulator would need to have a minimal rating of 12V * 2A = 24 watts. A potentiometer, that is made for 12 volt applications, should be available at a local auto parts store. It has a simple, ceramic insulated, wire-wound resistor, and should have a 5 to 10 amp rating Sources below are to more sophisticated controllers than a simple potentiometer.
You need to be aware if you slow do a pump it will pump less and produce less pressure. Running slower it might not be able to overcome the resistance in the discharge piping.
A more efficient way would be to use a PWM controller which wastes less energy. Luckily these are available as modules now for motor speed control, so are plug and play with a variable control knob on the front. Just make sure you pick one suitable for your voltage range.
