Carguy3J
Explorer Addict
- Joined
- June 21, 2008
- Messages
- 1,525
- Reaction score
- 3
- City, State
- North East New Jersey
- Year, Model & Trim Level
- '99 4dr. XLT SOHC A4WD
Ok, so I did an e-fan on my '93 Ranger. I used a Volvo fan. It was, I think, out of a V70/V90 or something. It pulls a ton of air. Unfortunately, it also pulls a ton of amps. Too much for the the alternator to keep up with while sitting in traffic at idle. The fan is a single speed fan, in that there is only a single power wire, and a single ground wire going into the motor.
My truck doesn't currently have a/c, but I just bought a parts truck with all the parts I need. Typically, when a/c is turned on, it triggers a relay to power the e-fan, on vehicles factory equipped, in order to ensure airflow over the condenser. However, I don't think I need the full speed this fan is capable of, for that purpose. I also don't think the electrical/charging system could handle it running all the time I would want the a/c on. I know that there are expensive fan controllers capable of regulating speed via PWM, but I don't want to spend a bunch of money on one.
The question is, can I safely run the e-fan at a slower speed, by reducing the supply voltage too it? I'm thinking the A/C clutch wire would trigger a relay supplying a secondary power supply to the fan, with a voltage reducer inline. Then, when the regular temp-based controller turns on, it can just send normal full voltage to the fan.
Will this work?
A.) Will reduced voltage also equal slower fan speed and reduced current draw (amperage)?
B.) Will this harm the fan motor?
D.) Do I need to worry about or protect against "backfeeding" full 12-14v, from the temp controlled circuit, into the reduced voltage circuit, when the full voltage side activates?
E.) What is the approximate relationship between voltage reduction and fan speed reduction, as well as current draw reduction?
It appears that the fan currently draws about 40amps.
My truck doesn't currently have a/c, but I just bought a parts truck with all the parts I need. Typically, when a/c is turned on, it triggers a relay to power the e-fan, on vehicles factory equipped, in order to ensure airflow over the condenser. However, I don't think I need the full speed this fan is capable of, for that purpose. I also don't think the electrical/charging system could handle it running all the time I would want the a/c on. I know that there are expensive fan controllers capable of regulating speed via PWM, but I don't want to spend a bunch of money on one.
The question is, can I safely run the e-fan at a slower speed, by reducing the supply voltage too it? I'm thinking the A/C clutch wire would trigger a relay supplying a secondary power supply to the fan, with a voltage reducer inline. Then, when the regular temp-based controller turns on, it can just send normal full voltage to the fan.
Will this work?
A.) Will reduced voltage also equal slower fan speed and reduced current draw (amperage)?
B.) Will this harm the fan motor?
D.) Do I need to worry about or protect against "backfeeding" full 12-14v, from the temp controlled circuit, into the reduced voltage circuit, when the full voltage side activates?
E.) What is the approximate relationship between voltage reduction and fan speed reduction, as well as current draw reduction?
It appears that the fan currently draws about 40amps.