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Discussion Topic:
Electric cooling fans .
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Gary M. |
06-11-2012 @ 5:41 PM
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Posts: 218
Joined: Oct 2009
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Is it possible to convert a 12v cooling fan to use on a 6v system so that it spins at the correct rpm`s . I already have the fan and would like to put it to use as an auxillary cooling source. Thanks....
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supereal |
06-12-2012 @ 7:15 AM
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Senior
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Joined: Oct 2009
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The short answer is no. Electric fans draw high current, often thirty or more amps, so the usual voltage droppers can't handle the load. In any case, a relay is required, as most switches are too light.
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joe b |
06-12-2012 @ 7:55 AM
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Gary, I know you asked about converting but if you want to buy an electric cooling fan try Scott's Cooling Fans. They have a large selection of 6 volt fans and offer either pos or neg ground. scottscoolingfans@yahoo.com
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Gary M. |
06-12-2012 @ 6:48 PM
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Posts: 218
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If I do use the 12v fan with a 6v system it will only spin at half speed,which is still helpful in cooling. However,Im mot sure if this is damaging to the fan or the electrical system. Any ideas? Thanks...
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fomocoloco |
06-15-2012 @ 5:03 AM
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if in fact your fan spins at half speed, i would think that would greatly reduce the cooling, heat the fan up, and be in the way of the air flow. buy a 14" 6v fan. install it behind the radiator (pulling), and install a 6v, neg. ground, two wire alternator to power it.
weezer
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daoust |
06-15-2012 @ 12:48 PM
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They certainly make 6V elerctric fans because I just un-installed one to get ready for concourse judging.
David Daoust
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Old Henry |
06-15-2012 @ 3:05 PM
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If you have a 6 volt alternator you could probably run the 12 volt fan at half speed but a 6 volt generator will probably not be worth the effort, especially since the generator doesn't put out much below 30 mph anyway which is when you would benefit most by the fan. Bench test the fan hooked up to your 6 volt battery and see what you get on the battery alone. Then run it with the engine running and watch the amp gauge. If the amp gauge shows the battery discharging even at high RPM's you'll know the generator isn't carrying the load and isn't going to work. The fan motor won't be harmed by running on 1/2 voltage. If the generator puts out enough to charge the battery and run the fan at the same time it won't hurt the generator. You just may not get enough cooling assistance when you need it at low speed to be worth the effort. I know that in the winter when I'm driving at night with the brights on, the spot light on, the heater fan on full, and the radio on if I don't leave home with a fully charged battery the generator will not charge it up and eventually the battery is dead. That's how weak the 6 volt generators are. And that's a newly rebuilt one. I believe that's why we don't even have electric windshield wipers but just vacuum operated ones. Old Henry (The older I get, the better old looks.)
This message was edited by Old Henry on 6-15-12 @ 3:41 PM
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Gary M. |
06-15-2012 @ 6:18 PM
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Posts: 218
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The car has the original 6v pos grnd system,however,I have a 12v power inverter that runs only a modern radio and nothing else. I dont know how many amps the inverter puts out but i would think that it can handle the radio and the fan. I will check the specs on everything and see if its possible. Does anybody else run more than one item on a 12v inverter ? Thanks...
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supereal |
06-15-2012 @ 6:45 PM
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Senior
Posts: 6819
Joined: Oct 2009
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Most inverters can't produce the required current for electric fans. They usually demand 30 or more amps, more than most generators provide. If you go to an alternator, be sure it is a two wire type. A one-wire variety usually won't do it. I don't like electric fans, anyway. They block radiator air flow. If your cooling system is in good shape you don't need it
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Old Henry |
06-15-2012 @ 11:19 PM
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You can find out how many amps your fan will draw by measuring its resistance in ohms and use this calculator to figure it out. That will give you more of an idea what is going to draw on your generator. Fans I've checked into are anywhere from 15 amps to 25 amps. Your stock generator is rated at 30 amps or 220 watts so if your fan draws 25 amps it would be close if you run the fan and almost anything else even at high speed. Below 30 mph you'd most likely be draining the battery. Here's the calculator: http://www.the12volt.com/ohm/ohmslawcalculators.asp Old Henry (The older I get, the better old looks.)
This message was edited by Old Henry on 6-15-12 @ 11:23 PM
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