Electric Fan Voltage Drop

When the air is on and the auxiliary electric fan kicks in my voltage drops from 14 2 down to about 12 5 13.

Electric fan voltage drop. 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. There must be little or no voltage drop at the fan motors. The alternator is tricked into working harder to compensate for the 1 2v difference it is seeing.

The actual voltage drop can vary depend on the condition of the wire the conduit being used the temperature the connector the frequency etc. The voltage drop test is a dynamic test intended for use mainly with high current draw systems such as the starting system charging system or items such as a heater fan electric fuel pump or. If dip to 11 volts then your alternator is either not delivering the 100 amps or the fan belt is slipping. What the diode does is drops the voltage by about.

It is recommended that the voltage drop should be less than 5 under the fully loaded condition. I have never had any problem with the battery going dead or any long term charging issues. Put a diode in series at the alternator on the excite trigger wire. Grab a volt meter and measure the voltage at the alternator.

Basic voltage drop law v drop ir. You may double the fan belt or use a serpentine belt so it won t slip.