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Mod | | | Forums66 Topics128,036 Posts1,055,454 Members48,422 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Nov 2009 Posts: 110 Wrench Fetcher | | Wrench Fetcher Joined: Nov 2009 Posts: 110 | I am curently working on putting together my own wire harness for my 51 1/2 ton chevy. The engine is a 250 with a one wire alternator. After searching and reading almost every post on wiring a one wire alternator...I am confused. Previous posts give two options to wire a single wire alt. 1. Take a wire from the alt terminal and connect it to the wire on the "B" terminal on the old regulator. The old regulator gets thrown away and the remainig wires get cut. This leaves the (correct me if I am wrong) alternator connected to the "b" terminal on the ignition switch. 2. Take a wire and connect the alt terminal to one of the posts of the amp meter and take another wire to connect from the second amp meter post to the starter.
Are these both connections correct and will these achieve the same goal while keeping the amp meter working?
Thank you, this is my first time ever working on electircal and I just want to get things right. | | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | Ya'll might want to read this article before you get to far into your project. Denny Graham Sandwich, IL
Denny G Sandwich, IL
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Here is a write-up on a one-wire alternator. At the bottom of the information is: How to wire to your vehicleAll that is "required" is to run a heavy, at least 10 gauge wire from the BAT terminal to the positive (+) post of your battery. I would suggest you connect it through the AMP meter. Depending on the information you want, there are a couple of ways to wire the meter. The first, and preferred, is to measure the charge/discharge of the battery. The other is to measure alternator output. The alternator output also includes the current draw of the lights etc. of the vehicle. Alternator output is best measured by voltage not current. The charge/discharge method tells whether the battery is charging or discharging. Here is the schematic shown in that article. This has worked well for me for 13 years (with ammeter working fine, the battery charges, no external voltage regulator, and the alternator "excites" at about 800 rpm). | | | | | Joined: Oct 2006 Posts: 9,671 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 9,671 | But Tim, I hope your not idling at 800 rpm after she's broke-in? That's the problem that the article poses. It's not charging at idle. I've been stuck at some large annual town car show while they staged us for an hour or more idling before they got us parked. With my generator I do just throttle it up to keep the battery charged. Nothing more embarrassing than to hit the foot switch and just hear that groan come from under the hood. There is always that guy with the muscle car next to you that someone else built for him that offers sage advice about the necessity of proper grounding. DG
Last edited by Denny Graham; 10/23/2010 5:16 PM.
Denny G Sandwich, IL
| | | | | Joined: Nov 2009 Posts: 110 Wrench Fetcher | | Wrench Fetcher Joined: Nov 2009 Posts: 110 | That was some good reading and inside on how an alternator works. I wasn't aware of the rpn requirement prior to start charging deal, it is a good thing you mentioned this article I am going to replace the internal regulator just to be on the safe side. I was wondering if the internal regulator for the one wire and three wires are the same, since I have a one wire without the field and sensing plug on top? | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Denny,
Once a one-wire alternator "kicks-in" at between 600-1200 rpm (a fast idle at start-up does it), it continues to charge at all RPMs. An alternator typically charges in the "+" range at much lower RPMs than a generator does.
I do not use an alternator on my "restored" 6v trucks, they use 6v original generators (and are often in the "-" range when idling, especially with the lights or radio on).
| | | | | Joined: Nov 2009 Posts: 110 Wrench Fetcher | | Wrench Fetcher Joined: Nov 2009 Posts: 110 | Are all one wire alternators self-energizing? Those that mean that they don't need to reach a certain level of RPM to work? The article above mentioned that to make a 3 wire self energixing one has to change the regulator....that left me wondering if that means the one wire is self energixing. I guess this other article also opened up the question for me. http://www.classictruckshop.com/one_wire.php | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | | | |
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