I have a 12v DC (rotary vane type) pump that is connected to a 12v auxillary battery. The battery is 12vDC 70Ah and it charges itself with the truck's alternator, which is 12 volts, 35 amps. the pump is 1/4 hp, and it draws 20 amps max. The problem is, the discharge output of the pump is very low(8-10lpm), whereas the pump is designed to have a max discharge of upto 57lpm. What is the reason of low discharge? Is there any way to increase the speed of the pump so that the discharge rate is increased?