Electric Fan Voltage Drop

What the diode does is drops the voltage by about.

Electric fan voltage drop.

The alternator is tricked into working harder to compensate for the 1 2v difference it is seeing. Might help you a lot with the voltages your are seeing. I switched to a 170 amp holley alternator along with a new drive setup on my ls and added a 4 awg feed wire. If dip to 11 volts then your alternator is either not delivering the 100 amps or the fan belt is slipping.

Put a diode in series at the alternator on the excite trigger wire. The actual voltage drop can vary depend on the condition of the wire the conduit being used the temperature the connector the frequency etc. Voltage would start off at 14 0 and drop down to 12 5 with both fans on entropy fans are big power hogs and everything else on. You may double the fan belt or use a serpentine belt so it won t slip.

Basic voltage drop law v drop ir. If does not drop then run a heavyer gauge wire between the alternator and junction terminal. There must be little or no voltage drop at the fan motors. Grab a volt meter and measure the voltage at the alternator.

It is recommended that the voltage drop should be less than 5 under the fully loaded condition. When the air is on and the auxiliary electric fan kicks in my voltage drops from 14 2 down to about 12 5 13.