[alanw]

Originally Posted by beef78

If you use math and stuff you should figure out that when you use a pump rated for 12 volt on a 6 volt system, it will draw twice the current. Which means a 6 volt 10 amp battery would last half as long as a 12 volt 10 amp battery.

That just doesn't sound right according to Ohm's Law.

V = I * R

Voltage = Current * Resistance


The resistance of the motor is a constant, so the only things that can change is volts and current which means that as voltage goes down so does current.

That means that a 6 volt 10 amp battery should last longer than a 12 volt 10 amp battery.