One wire alternator hook up

Birch motor cars · 03-17-2017, 11:24 PM

Anyone running a one wire alternator on a small block chevy ? My battery is in the trunk,do you run the wire to the battery or to the disconnect switch at the rear of the car ?

Jeff Stout · 03-18-2017, 10:16 AM

Ive run my to the battery for years with no trouble. I did forgot to reinstall wire once when I pulled motor and batteries were up in the beginning of race and later in the day batteries went down and wouldn't start. Checked things out and saw the alternator wire just sitting next to battery and not connected. Dumb mistake.

Eman · 03-18-2017, 08:56 PM

You can run it back directly to the battery...but it defeats the purpose of having a cutoff switch at the back of the car. The cutoff will shut the car off but it obviously won't kill all power since that alt wire will still be hot. And for the alt to charge properly you really should use a heavy cable like a #4 all the way back.
There's a few ways to accomplish shutting off all of the power. One is with a continuous duty solenoid or relay. It will only activate when the batt switch is on and shut power to the alt. when the batt switch is off. you can also buy a double pole single throw cutoff switch like a Moroso 74102 or a Cole hersee 75912. it has an extra set of contacts that shut the alt power off

FireSale · 03-19-2017, 01:13 AM

I run a 1 wire from East Coast Auto Electric in my Mustang. Wired directly back to the battery through a double pole cutoff from Moroso. Switch on the back kills everything. No run on. The only thing I don't like is that I lost my cockpit cut off lever in the setup. I could rig it back in but NHRA says one cutoff only.

Barneyb · 03-20-2017, 08:48 AM

When I wire cars I run 6 gauge wire from the alternater to a relay back by the battery then from it to the battery. I hook the relay wire up to your ignition so the wire going all the way up the car to the alternator is dead unles you have your ignition on.
BB

Rusty Davenport · 03-20-2017, 10:47 AM

Not trying to steal the post but does it damage the alternator when routinely charging the battery ???

Eman · 03-20-2017, 10:59 AM

It's never hurt mine to charge. I run a one wire alt but I hook the charger up while cooling with water pump and fan on. My alt has been hooked directly to the battery and didn't give problems.
One side note about hooking directly to the battery. If your 1 wire alt does go bad it usually creates a drain on the battery. It will still charge but when the car is off it will drain the battery down.

03-17-2017, 11:24 PM	#1
Birch motor cars Junior Member Join Date: Jul 2016 Location: NW Iowa Posts: 40 Likes: 1 Liked 3 Times in 1 Post	One wire alternator hook up Anyone running a one wire alternator on a small block chevy ? My battery is in the trunk,do you run the wire to the battery or to the disconnect switch at the rear of the car ?

03-18-2017, 10:16 AM	#2
Jeff Stout VIP Member Join Date: Dec 2001 Location: phoenix Posts: 1,409 Likes: 53 Liked 655 Times in 255 Posts	Re: One wire alternator hook up Ive run my to the battery for years with no trouble. I did forgot to reinstall wire once when I pulled motor and batteries were up in the beginning of race and later in the day batteries went down and wouldn't start. Checked things out and saw the alternator wire just sitting next to battery and not connected. Dumb mistake.

03-18-2017, 08:56 PM	#3
Eman Member Join Date: May 2014 Location: E TN Posts: 441 Likes: 14 Liked 105 Times in 60 Posts	Re: One wire alternator hook up You can run it back directly to the battery...but it defeats the purpose of having a cutoff switch at the back of the car. The cutoff will shut the car off but it obviously won't kill all power since that alt wire will still be hot. And for the alt to charge properly you really should use a heavy cable like a #4 all the way back. There's a few ways to accomplish shutting off all of the power. One is with a continuous duty solenoid or relay. It will only activate when the batt switch is on and shut power to the alt. when the batt switch is off. you can also buy a double pole single throw cutoff switch like a Moroso 74102 or a Cole hersee 75912. it has an extra set of contacts that shut the alt power off

03-20-2017, 08:48 AM	#5
Barneyb Junior Member Join Date: Feb 2017 Location: Wadsworth, Ohio Posts: 9 Likes: 0 Liked 0 Times in 0 Posts	Re: One wire alternator hook up When I wire cars I run 6 gauge wire from the alternater to a relay back by the battery then from it to the battery. I hook the relay wire up to your ignition so the wire going all the way up the car to the alternator is dead unles you have your ignition on. BB

03-20-2017, 10:47 AM	#6
Rusty Davenport Senior Member Join Date: Jun 2005 Location: Nashville N.C. Posts: 505 Likes: 4 Liked 100 Times in 26 Posts	Re: One wire alternator hook up Not trying to steal the post but does it damage the alternator when routinely charging the battery ??? __________________ NHRA AND IHRA STOCK ELIMINATOR 2772

03-19-2017, 01:13 AM	#4
FireSale VIP Member Join Date: Feb 2014 Location: Lakewood Washington Posts: 1,407 Likes: 29 Liked 236 Times in 127 Posts	Re: One wire alternator hook up I run a 1 wire from East Coast Auto Electric in my Mustang. Wired directly back to the battery through a double pole cutoff from Moroso. Switch on the back kills everything. No run on. The only thing I don't like is that I lost my cockpit cut off lever in the setup. I could rig it back in but NHRA says one cutoff only. __________________ Dale Shearon 68 Mustang 6394

03-20-2017, 10:59 AM	#7
Eman Member Join Date: May 2014 Location: E TN Posts: 441 Likes: 14 Liked 105 Times in 60 Posts	Re: One wire alternator hook up It's never hurt mine to charge. I run a one wire alt but I hook the charger up while cooling with water pump and fan on. My alt has been hooked directly to the battery and didn't give problems. One side note about hooking directly to the battery. If your 1 wire alt does go bad it usually creates a drain on the battery. It will still charge but when the car is off it will drain the battery down.