The Stovebolt Site Forums The Shop Area The Electrical Bay Electirc Fan

I'm thinking of installing an electric fan on my radiator to get some extra cooling when I'm sitting still or in stop & go traffic. Will an axillary fan work off my stock generator, or will I have to change over to an alternator.

I'll hook it up to a switch under the dash and use it only when necessary.

Thanks
George

Whatever you do, you need a relay.

You will need an alternator. The gen. doesn,t put out enough curent at idle & slow speed to power the fan. Inky is right about the relay.

I am going to disagree with the other responses.

An average electric fan draws about 15 amps. There are some 30A killer fans you can buy as well as some 10 amp ones. For example:
Fans - take your pick

You can buy toggle switches rated at 30 amps which should eliminate the need for a relay. (The Bosch relay everyone is fond of is rated at 30 amps)
Heavy duty switch

I assume you must have already converted to 12 volt if you are considering the fan. I don't know if there are 6 volt radiator fans available.

If your generator puts out 40 amps (typical) you should be ok as long as the battery is good and you don't operate a lot of other things and you probably won't need the fan at night when the lights are on.

So I say go ahead, but keep an eye on the ammeter. We all do that anyway, right? if the ammeter is constantly on the discharge side, turn the fan off.

I have an electric fan on my '49 with a 12 volt generator. Yeah, it'll discharge if you stop at a stop sign, but, it comes right back.

Thanks guys I think I'll give a try. I only need the extra air flow when it gets real hot, other wise I have no problems.

My radiator has never boiled over but the guage goes up midway into the red sometimes. I probably should check the actual temp of the water in the radiator when the guage shows hot before I go to the expense of buying a fan.

The radiator has been rodded out and a new filler neck installed so that I can run a 7lb cap.

Thanks
George

How do you intend to check the actual water temp when the gauge shows hot? Removing the radiator cap at that time can be dangerous.

I replaced my mechanical fan with a 16-inch electric fan and had some problems with pwer surges (when it kicked on) even with a 90 amp alternator ... until I installed double relays AND switched from circuit-breaker to fusible link.

All my info can be viewed Here

And, if you aren't fully aware about fusible links, Read This

Both 6-volt and 12-volt electric radiator cooling fans are available. Also most important check to see how the fan motor is made. Most are made using bushing motors which are less efficent and draw more current. By contrast a ball bearing motor will draw less current and have a much longer service life. They do cost more to manf but like most things you get what you pay for.... The fan motors I use to build fans with are ball bearing motors and draw five amps at 2587 rpms. A bushing motor will typically draw about twice that. In the case of 6 volt it makes quite a difference how efficent things are. A 30 amp toggle switch and inline fuse are included along with real mounting brackets to mount the fan to the radiator instead of the wire ties that will wear a hole in your core.

If the fan motor is efficent you can run a cooling fan with a generator, I have for going on 20 years, we do it on the Great Race cars every year. WE also do not use a relay but instead use a heavy 30 amp toggle switch. Over the years I have learned to believe in the kiss principle....

You can read more in the tech tips page at fifthaveinternetgarage.com Thanks Randy