The Ford Barn

EDavid · 09-09-2023, 10:43 AM

I've had my 31' for over 60 years. When I purchased the car (mostly at my dad's urging I believe he wanted it more than me). It Needed lots of work. My dad was the "Chief" mechanic and I learned by watching, listening and doing. My issue is I've decided to convert from the generator to an alternator, I never took notice before but my generator has 3 wires connected. One to the terminal box (standard), one to horn and one to the battery button within the lighting switch, Is this standard? Never had issues in the electrical system, Headlights (low and high beam) tail and stop lights OK and the little dash light OK. So just wire the alternator as the generator was.
Thanks
Edgar Smith Austin, Texas

jrelliott · 09-09-2023, 12:16 PM

Wire the three wires on the generator to the output terminal of the alternator. If you do put in an alternator you must disconnect the battery from the circuit or will run down your battery as the alternator draws current to energize the field. If you have a fuse mounted on the starter you can pull this fuse. Also the alternator will not start charging like a generator as the alternator needs to be sped up to start working. Have some information on how to solve the latter problem if you would like. You can email me at [email protected]

TomInCologne · 09-10-2023, 02:08 AM

Quote:

Originally Posted by jrelliott

Wire the three wires on the generator to the output terminal of the alternator. If you do put in an alternator you must disconnect the battery from the circuit or will run down your battery as the alternator draws current to energize the field. If you have a fuse mounted on the starter you can pull this fuse. Also the alternator will not start charging like a generator as the alternator needs to be sped up to start working. Have some information on how to solve the latter problem if you would like. You can email me at [email protected]

Hmm, my alternator has some diodes to prevent the alternator discharging the battery when the engine is off. I think that is standard, is it not? And from about 420rpm my alternator (Powermaster) charges my battery says my ampmeter...

nkaminar · 09-10-2023, 07:10 AM

An alternator has diodes and diodes have a small reverse voltage leakage current. So the alternator has a small leakage current that should not bother the battery if the car sits for a short time (a couple months). The battery has a small leakage current too that will cause the battery to discharge over a year or more. If the car sits in storage for a while (months) hook up a battery maintainer. Do not use a battery charger as it can overcharge the battery and ruin it.

Regarding the wires. Just hook up the wires as they were on the generator. If you want to be extra cautious use fuses in the lines for the horn and lights in addition to the fuse that goes to the ignition system. One problem with having one fuse for the entire car is that if the lights short and blow the fuse, the engine will stop running. That could be a problem in the middle of an intersection.

Y-Blockhead · 09-10-2023, 08:38 AM

Quote:

Originally Posted by nkaminar

One problem with having one fuse for the entire car is that if the lights short and blow the fuse, the engine will stop running. That could be a problem in the middle of an intersection.

Yes, my car "tested" that theory one evening.

I now have a circuit breaker on my headlights and a fuse box hidden under the gas tank.

MAG · 09-10-2023, 01:30 PM

Sponsored Links (Register now to hide all advertisements)

"If you do put in an alternator you must disconnect the battery from the circuit or will run down your battery as the alternator draws current to energize the field."

If the back resistance in one or more of the diodes in the diode pack is bad it can run the battery down. But if they are are all good they will not cause a discharge of the battery. If the car is going to be put in storage it might be well to disconnect the battery.

ndnchf · 09-10-2023, 03:28 PM

You've had your car for over 60 years and never had an electrical problem. That is fantastic - well done. But I have to ask - why do you want to change to an alternator after all this time? The generator has proven itself. A properly rebuilt generator will offer many more years of trouble free service.

09-09-2023, 10:43 AM	#1
EDavid Junior Member Join Date: May 2021 Location: Austin, Texas Posts: 6	Generator/Alternator I've had my 31' for over 60 years. When I purchased the car (mostly at my dad's urging I believe he wanted it more than me). It Needed lots of work. My dad was the "Chief" mechanic and I learned by watching, listening and doing. My issue is I've decided to convert from the generator to an alternator, I never took notice before but my generator has 3 wires connected. One to the terminal box (standard), one to horn and one to the battery button within the lighting switch, Is this standard? Never had issues in the electrical system, Headlights (low and high beam) tail and stop lights OK and the little dash light OK. So just wire the alternator as the generator was. Thanks Edgar Smith Austin, Texas

09-09-2023, 12:16 PM	#2
jrelliott Senior Member Join Date: May 2010 Location: Pine, AZ Posts: 794	Re: Generator/Alternator Wire the three wires on the generator to the output terminal of the alternator. If you do put in an alternator you must disconnect the battery from the circuit or will run down your battery as the alternator draws current to energize the field. If you have a fuse mounted on the starter you can pull this fuse. Also the alternator will not start charging like a generator as the alternator needs to be sped up to start working. Have some information on how to solve the latter problem if you would like. You can email me at [email protected]

09-10-2023, 07:10 AM	#4
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: Generator/Alternator An alternator has diodes and diodes have a small reverse voltage leakage current. So the alternator has a small leakage current that should not bother the battery if the car sits for a short time (a couple months). The battery has a small leakage current too that will cause the battery to discharge over a year or more. If the car sits in storage for a while (months) hook up a battery maintainer. Do not use a battery charger as it can overcharge the battery and ruin it. Regarding the wires. Just hook up the wires as they were on the generator. If you want to be extra cautious use fuses in the lines for the horn and lights in addition to the fuse that goes to the ignition system. One problem with having one fuse for the entire car is that if the lights short and blow the fuse, the engine will stop running. That could be a problem in the middle of an intersection. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

09-10-2023, 01:30 PM	#6
MAG Senior Member Join Date: May 2010 Location: Austin, Texas Posts: 925	Re: Generator/Alternator Sponsored Links (Register now to hide all advertisements) "If you do put in an alternator you must disconnect the battery from the circuit or will run down your battery as the alternator draws current to energize the field." If the back resistance in one or more of the diodes in the diode pack is bad it can run the battery down. But if they are are all good they will not cause a discharge of the battery. If the car is going to be put in storage it might be well to disconnect the battery. __________________ I noticed the harder I work the luckier I get!

09-10-2023, 03:28 PM	#7
ndnchf Senior Member Join Date: May 2012 Location: Fredericksburg, Virginia Posts: 762	Re: Generator/Alternator You've had your car for over 60 years and never had an electrical problem. That is fantastic - well done. But I have to ask - why do you want to change to an alternator after all this time? The generator has proven itself. A properly rebuilt generator will offer many more years of trouble free service.