Electric Fan Voltage Drop

Might help you a lot with the voltages your are seeing.

Electric fan voltage drop.

If dip to 11 volts then your alternator is either not delivering the 100 amps or the fan belt is slipping. 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. When the air is on and the auxiliary electric fan kicks in my voltage drops from 14 2 down to about 12 5 13. There must be little or no voltage drop at the fan motors.

Grab a volt meter and measure the voltage at the alternator. 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. What the diode does is drops the voltage by about.

Basic voltage drop law v drop ir. 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. When electric fan installs don t perform as expected the problems are often traceable to under wiring and or poor splices and grounds.

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. If does not drop then run a heavyer gauge wire between the alternator and junction terminal.