- Aug 13, 2011
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- vr commo
You are some watt correct. But amps will not flow without volts. If a load only has half it's rated volts not all the current will flow.Not how electricity works. If you increase the voltsge it will draw less current. The power (watts) is constant.
P=VI - at 14.4V the power consumed is 14.4V x 40A = 576W
If you add the diode and take it to 15V output the current will reduce as the load has not changed - it will still require 576W to power it
I=P/V so 576W/15V = 38.4A - less current is required as more voltage has been applied.
This 15V is now overcharging your battery - it won't kill it today but you won't be getting 4 years out of it either. It is a slow and painful death for the poor old thing.
The draw on the alternator's power has not changed - theoretically. In practive you need to provide additional power to the field windings in order to increase the magnetic field to produce the additional voltage so the motor has to work harder to drive the armature to cut the field so the additioanl power requred to do this comes from the engine (motive power) not the alternator Nothing is free.
The resistance is constant regardless of the voltage - resistance from the cables and components does not change (theoretically) however, heat and other variables come into effect in real life situations.