1 wire Alt and electric fan

37pickupproject

37pickupproject

Member
Put a walker radiator in my 37 and the mechanical fan does not clear the top tank. I'm running a 60 amp one wire Alternator on top of my flattie(12volts). I was going to use a cooling components 2 speed electric fan capable of pulling 2500 CFM (CCI-1770) in place of the mechanical fan. (Open to other electric fan suggestions)

The fan pulls 60+ amps on intial startup and has a normal operating range of 16-22 amps. Will my alternator be large enough if it only pulls high amperage on startup? Will the original wire that went to the cutout be a large enough gauge for the alternator or should I run a seperate wire straight to the starter solenoid? I wanted to retain the ammeter If I could using the original wire.
 
I put one on my 53 Victoria, running lights and etc I was on the edge of not having enough amperage to operate everything, put on 100 amp alternator took care everything.
The wire I assume is for 6 volts if it is should handle all.
 
You would have to do a charging system output test, most alternators are rated cold, the hot output is quite a bit less, and the belt/pulley may not be able to spin the alternator at full load without slipping (this is why I say to do output test of the charging system on the car so you know what you have to work with)
 
Your starter pulls about 200 amps on startup, which it gets from the battery.

Your fan will also get it's start from the battery. The alternator is about replenishment of battery, not source of running current, unless your continuous draw exceeds alternator output. The rest is just the arithmetic of adding up everything that will draw current while driving. I'd say that unless you're running a high output sound system, these early cars draw very little current while running and 60 amps is probably plenty.
 
If you consider the original generator output in the 20 Amp range and the alternator at 60 Amps there is a 40 Amp difference. Now the question is what is the alternator actually producing and are there any additional current draws added to the car?
 
Thinking out loud again, how come these late rice burners have alternator big as a
base ball and a lot have two fans and they work?? I would have a relay with 10ga.
wire, wired direct to batt or solonoid. do you have a temp sensor? If not I have
used a Napa adjustable sensor (probe type stuck in the radiator) then that wired into
the relay. New alum radiators claim direct fit not so they have no cut out underneath
the tank for the fan. And then my loader has like 18 or 20 inch fan and it has also
a 60 amp alt and with all lights on fan on the alt is still maintaining..
 
The battery will handle the fan start-up surge if the alternator doesn't. I have a 65 amp alternator and used #8 wire for both power out and a ground off the case of it.
 
37pickupproject said:
Put a walker radiator in my 37 and the mechanical fan does not clear the top tank. I'm running a 60 amp one wire Alternator on top of my flattie(12volts). I was going to use a cooling components 2 speed electric fan capable of pulling 2500 CFM (CCI-1770) in place of the mechanical fan. (Open to other electric fan suggestions)

The fan pulls 60+ amps on intial startup and has a normal operating range of 16-22 amps. Will my alternator be large enough if it only pulls high amperage on startup? Will the original wire that went to the cutout be a large enough gauge for the alternator or should I run a seperate wire straight to the starter solenoid? I wanted to retain the ammeter If I could using the original wire.
Click to expand...
Relative to your mechanical fan not clearing the top tank are you sure you have the correct intake manifold? The made several heights and the '37 was one of the shortest. How about a picture?

Charlie Stephens
 
I am running a 4 barrel manifold so the manifold height could be a factor but it doesn't clear because the tank doesn't have the fan cut out. I was going to use a pulley on the alternator allowing the bolt on of original fan. I'll just use the regular pulley on the alternator now.

I was mostly concerned about idling in traffic as the alternator wouldn't be spinning fast enough to allow for a full load and the fan may kick on and off often. Sounds like I will have to wait until I get it running to do an alternator output test so I really know how much it is producing.

The truck won't have any other aftermarket accessories just the lights, no radio. I think the original wire for the cutout is only about a 12 gauge, not sure what that can hande.
 
Amen on the relay, preferably operated by a coolant temperature sensor. Look for a current demand number on your fan or with the printed material. Fans usually require from 20 to 50 amps, depending upon the size. We use #8 wire to the battery side of the starter solenoid. Most require a 12 volt system with a high output alternator if you plan to carry the lighting load, particularly driving at night in traffic.
 
37pickupproject said:
Put a walker radiator in my 37 and the mechanical fan does not clear the top tank. I'm running a 60 amp one wire Alternator on top of my flattie(12volts). I was going to use a cooling components 2 speed electric fan capable of pulling 2500 CFM (CCI-1770) in place of the mechanical fan. (Open to other electric fan suggestions)

The fan pulls 60+ amps on intial startup and has a normal operating range of 16-22 amps. Will my alternator be large enough if it only pulls high amperage on startup? Will the original wire that went to the cutout be a large enough gauge for the alternator or should I run a seperate wire straight to the starter solenoid? I wanted to retain the ammeter If I could using the original wire.
Click to expand...
I'm running a 58A GM alternator with elect. fan, heater. CD player/amp, halogen lights, running lights, 3rd brake light and gauge never goes to discharge.
 
Recommend (1) at least a 30 amp relay, better a 70 .... just google on internet, and (2) you should be able to shut-off the fan(s) after you shut-off engine .... such as with a manual switch at dash or better yet using a relay wired to your ignition switch .... reason ? fan controls can fail allowing the fan to continue to run, draining your battery, long after you park in front of a TV.
 
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