Electric Fan Voltage Drop

There must be little or no voltage drop at the fan motors.

Electric fan voltage drop.

I have never had any problem with the battery going dead or any long term charging issues. When the air is on and the auxiliary electric fan kicks in my voltage drops from 14 2 down to about 12 5 13. 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. The alternator is tricked into working harder to compensate for the 1 2v difference it is 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. When electric fan installs don t perform as expected the problems are often traceable to under wiring and or poor splices and grounds. You may double the fan belt or use a serpentine belt so it won t slip. If dip to 11 volts then your alternator is either not delivering the 100 amps or the fan belt is slipping.

The actual voltage drop can vary depend on the condition of the wire the conduit being used the temperature the connector the frequency etc. It is recommended that the voltage drop should be less than 5 under the fully loaded condition. Put a diode in series at the alternator on the excite trigger wire. What the diode does is drops the voltage by about.

Basic voltage drop law v drop ir. If does not drop then run a heavyer gauge wire between the alternator and junction terminal.