I have a small water pump to water my flowers. To control it, I want to know how much power is used. So I put it in a jar and powered it on.
I connect the pump to my bench power supply and test:
|3.3||0.33||1.1||Slow, but working|
|8.4||0.77||6.4||Even more flow|
|12||1.25||15.0||Very strong flow|
The flow seems to increase exponentially with the voltage and is corresponding with the Wattage. Since my project uses li-ion batteries which can provide 6.6 to 8.4 volts with 2 batteries the flow is ok, but not too strong. Maybe another battery would be an idea to increase the voltage to 9.9-12.6 volts.
On the other hand my batteries are solar powered and should therefore have enough power when the weather is nice and more water is needed.
I will use a IRLD024 mosfet which can switch 1.8 amps to control the pump since the relay was not reliable enough and drained too much power.