alternator conversion

Hello all,
I'm new to this page which explains why I posted this message in the intermediates page first. I am currently rebuilding a '62 CJ5 and have it down to the frame. The engine is on a stand and while its out I was thinking about replacing the generator with an alternator. Is there an advantage to this conversion? I was goig to use a Delco system, does anyone recommend any other system?
Thanks,
Brad

 

Hey Brad, 1st welcome.
Alot of the guys seem to run the 1 wire GM style. I'm leaning that way myself.
Gens are ok but alternators are readly available at parts houses. Also more amps made.

 

i'm new, but the jeep i just bought has the delco 1 wire, and it seems to be working well.

 

Go for it. Delco is very adaptable. 1 wire might be simpler, but the conventional si type with 3 wires is very simple.
-Hill

 

This discussion was just covered pretty well last week - one wire vs three wire. Seems the real difference is that with a three wire alternator you get the Warning (Alt) light to work on the cluster. With a one wire you need to monitor a gauge.

I use a one wire with a volt gauge.

 

Brad, yes, there are advantages. Mine just seems to run better overall with a the alt plus you can get a LOT more amperage out of an alternator than you can a generator. I ran the original gen in mine for awhile but I've been glad I switched it. I'm using a 10SI or 12SI (can't remember which) but it's an 80 amp, standard-issue Delco unit. Note that while we call these "one-wire" alts, there are actually 3 wires you hook up. There are true 1 wire units, but that's not what I used. Plenty of juice for extra lights and stuff. Easy to do. Willys Works in Arizona sells an adapter bracket kit that you'll need.

Stan

 

i have had zero problems with anything since i put my gm 140 amp 1 wire in.... i will never go back to a 3 wire again

 

This subject does come up regularly. But since it didn't seem to get correctly answered I thought I'd kick it back to the top. My conscience is getting to me as I recall reading an editorial in an 4 wheel drive magazine recently about how much mis-information is out on the forums. Let's work to keep this site a leader.

First, you don't want to use a 1 wire alternator. That is unless you are building a show quality hot rod with very few electrical accessories. If you have a 1 wire it does not matter what the amperage rating is. You will NEVER get anywhere near capacity out of it.

In a one 1 wire, the sensing wire is internal. Basically not much different from the 3 wires that have the sensing wire jumped directly to the batt post (output) on the back of the alternator. Yes the factory has done it this way. I was helping a friend install a Painless kit and was disappointed to see that even they suggest the jumper.

With the sensing wire attached to the post (or internally on a 1 wire) the alternator never gets a good "feel" for system voltage. Load draws the voltage down, the sensing wire "feels" this and starts to produce more current. As soon as it does the the sensing wire "feels" it and drops the current. It's similar to rapid cycling.

Consider this analogy. You have a furnace in your house and some "genius" mounts the thermostat right beside the heat output vent. Guess he wanted to save on wire!! Some cold winter night you set the thermostat and go to bed. As the temperature drops the thermostat senses this and turns on the furnace, which immediately begins to expell hot air from the vent. Of course the thermostat now senses the warmth and shuts off the furance. Rapid cycling. You are cold all night because the furnace is never on long enough to warm the house, it's only warming the thermostat!! That is very similar to how a 1wire alternator works.

Do your self a favor and move the "thermostat" to the other side of the house. Get a three wire (or 2) and route the sensing wire at least as far as the battery. Better yet, beyond, like the fuse panel. I re-call a good tech page that suggested running the sensing wire to the horn relay. Essentially, out into the far back corner of your electrical system.

That way the battery and alternator can do the work they were designed to do. Your system voltage will be higher (should be around 14.2 volts with the engine running). Your headlights will shine brighter, your electric fan will run faster and that HEI that you paid good money for will be producing the spark it should.

And if you have an upgraded alternator, absolutley increase the wire size from the alternator output to the battery. If it's over 100 amp use 8 or 10 gauge.

 

Boy Joe you don't post much, but when you do it's great stuff.

 

Something seems fishy about the above soliloquy. If those symptoms were the case, I or others would notice predictable symptoms. Has anyone? Not this cat. I've never noticed any lack of charge, and I run accessory lights, accessory heater, and a winch. And I'm running a 78 alt one wire. No probs here, and I'm delighted as all get-out to not deal with the multiple posts on the previous alt. It's why they call it an "upgrade".

CJ Joe, you raise the discussion to a high level, props for that. :stout:

 

when i changed the external reg for interal, the electerical shop guys told me to run both wires from the plug under the dash. install cheapie light on one leg and put both on the key on position on the ignition switch. works real good, "buries" volt meter on start up (gauge stops @ 18 volts) then drops down to 14 about 2 seconds later.

 

here's a drawing that may make this more clear:



This is another instance of our friend, the voltage divider. The loads are the things on your Jeep like lights, horn, engine, etc. The alternator will both charge the battery and directly power the load through the charge wire. I've shown the places you can connect the sense wire. When the load calls for current, there will be a voltage drop between the battery and the load due to the resistance of the wiring. This is the block labeled "wiring". If the sense wire is attached between the wiring and the load, whe sense wire will "see" the current drawn by the load, due to the voltage drop due to the wiring. This is the preferred connection. If the sense wire is connected at the battery, the circuit will still work, but the battery voltage will need to drop before the alternator is turned on. The preferred connection operates so that the alternator handles the load directly. I'd expect the preferred connection also is better for the battery, since after the Jeep starts, and the juice drained by starting is replaced, the battery only serves as a voltage reference for the rest of the system.

hth

 

What Tim said.

Joe didn't say the other ways wouldn't work, he just said to get the most out of the alt. capacity it should be hooked up like Tim is showing.

 

http://home.comcast.net/~jeepboy7/alternator.htm


Try this link

 

i'd have to go look at how mine is wired and where, but i do know that when my engine is at idle i have 14.2-14.4 volts at the battery. (checked with a fluke) i dont rememeber where my volt meter is reading from that that too reads 14 volts when running. so where would the best place be to get power from for your volt meter?

 

You and Joe have it right. This is the best way to do it. The one wire or the three wire hooked right to the Batt post work, but having the sensor wire reading from the fuse block or such is the textbook way to do it.
The alt conversion is a great idea for any old gen equpipped Jeep and it's easy to do.

 

He has a point here. However, I feel that the sense wire should be connected directly into that 10ga (or 8ga) wire that should be coming from the starter post. Where we hope that there is a really decent battery cable. This way the alternator is metering the battery. If you actually had the sense connected to the fuse box then there is a chance that the alternator would overcharge the battery. With the costs of Optima batteries these days, I prefer to sense the battery voltage. Works well on my rig! (until the wire fell off this weekend....) I was wondering what that red glow in the dash was... Hmmmmm.

-Hill