Follow-up: alternator opinion

Well,
I put a Delco-Remy 63 amp Alternator into the '68 CJ5. It fit perfectly, but I'm having trouble wirh the wiring. There is the large BAT terminal on the backside. That one was easy it went to a fat 10 or 12 guage wire which went to the Starter which went right to the positive cable on the battery.
Here is the problem, I started it and it is not putting out any charge. I'm about 99% certain that this is because the 2-pronged terminal coming out the side of the case is not wired up. I found out these are- field (#1 on left) and sensing (#2 on right). I am not 100% sure where these should go to. I dont have an ampere guage on the dash or anywhere else. Does anyone know where I should wire these to?

Sorry about all the reading.
Josh.

 

Let me get this straight. The red wire coming out of the two prong terminal can just be run to the back side and attached to the large BAT terminal? And the white wire does not need to be hooked up at all if you don't have a guage?

What did he mean by #2 on case? Just ground the #2(white) wire on the case of the alternator?

Thanks,
Josh

 

Anyone there? Help please.

 

It's been so long since I did this I can't remember the theory behind it, but...

The red wire can go to the Bat Terminal.

The white wire has a couple options. What is needs is 12 volts (well kinda) when the ignition is switched on. THIS IS THE WIRE THAT WILL MAKE THE AMP LIGHT WORK ON YOUR SPEEDO GAUGE. Run a wire from the ignition switch that is 12 volts hot when the key is on, run it to one side of the light bulb for the amp indicator on the speedo face, and then run the other wire from the bulb to the white wire on the alt. When you turn the key on the light will light up. When you start it the light will go out indicating the alt is charging. If it stays on it indicates a fault in the alt. Good diagnostic tool! The light bulb provides a slight resistance to the alt that it uses to "turn on" and start charging, that's why I said "12 volts kinda". If you don't want to run the light you still need some resistance in the wire and you can just go to radio shack and get a resistor and wire it inline on the white wire (again hot when ignition is on). Can't remember the specs on the resistor now but have it somewhere, can get it if you need.

I have read technical writeups that suggest that it is better to run the red wire to a 12 volt source away from the Bat terminal. This is because the alt uses this wire to adjust amp output. By looking right at the back of the case, it is seeing the results at the source, lke water flowing from a hose. By hooking up the wire at a 12 volt hot connection somewhere else, like on a junction block on the firewall somewhere, you are sensing further donwstream, like looking at the water at the end of the yard that you are watering with the hose, and can more accurately determine required output. WHEW, hope that makes some sense!

For the record, my white wire runs as described to the amp light on the speedo, and the red wire is hooked to Bat, and it works perfect. And has for 5 years.

The fat wire coming off the bat terminal can run to Bat positive, either straight to it or commonly to the starter where the Pos bat cable attaches. use whichever looks neater I say. I would recommend use a fusible link at the Bat terminal, you see that on some factory apps. Get a fus link rated just slightly above rated output, attach it to the bat terminal, and hook the other end to the 10-12 ga charge wire. Now if you ever get a short on the charge wire (rubs against frame and grounds out) instead of the alt sending its max amperage output downstream (which it will!), the fuse link will burn in half just like a fuse. This can save an expensive wiring harness meltdown at the least and a vehicle totaled by fire at the worst.

 

http://www.oldengine.org/unfaq/10si.htm

Good info.

 

instead of a fusible link, I would install a fuse and carry spares.

 

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

Another excellent write up touting the benefits of a standard 3 wire hookup over the 1 wire hookup, explains some of the theory on remote sensing I bumbled through earlier.

 

66cj5, I had a fuse link burn one time, due to a faulty regulator that had the alt putting out close to 18 volts. It was actually on a Chevy Blazer, and it totally died, no power anywhere. I ran a wire from the Bat to the HEI terminal and arced over the starter with a screwdriver. It ran but nothing else had power! This was at night, snowing, going up hill both ways, etc etc.
Next day found the burnt fuse link on the firewall, replaced it, replaced (actually home rebuilt, they are really simple) the alt, and motored on.

I understand the fuse idea. 10si alternators come in 42, 63, 80 amp outputs (that I have seen) I am sure there are others but these are ballparks. I think you would have to use one of those "big" fuses to get a rating that high. I would want a "sealed" fuse holder to prevent corrosion where the fuse plugged into the holder since it is under the hood. Keep in mind that fuse links are replaceable in the field with only a crimper and a butt splice. I guess you could even do the "twist together and electrical tape" for a "get home" situation. I carry a spare fuse link with the proper ring terminal on one end and the correct size butt splice the other. I think that is how a lot of them come from the store anyway. I would just need a wrench for the nut on the bat term and a crimper or pliers for the butt splice. I always carry both.

 

if i were to use a fuse setup i would go to your friendly (not really) local car audio place and get one for a amp. they can carry ALOT of current. IIRC mine for my old system was 200amp but then again that was a big one because i ran over 1000 watts. i know you can get 100 or so amp ones also. easy to replace the fuse when they break but the fuses are not cheap like $14 per fuse

 

What size fuse would you put in there?

Josh

 

Two things to keep in mind. First, to get the alt to start charging, in addition to hooking it up as outlined, you will probably need to rev the engine a bit to get the alt to start charging and get the alt light to go out. This is normal and no big deal.

The other thing is most of the time when people refer to a "one" wire alt, they are actually referring to a three wire GM style alt (i.e., a 10SI/12SI). There are true 1 wire alternators, but from what I've read these are best used on tractors and that sort of thing.

Stan

 

i would think if you had a 80 amp alt you would run something with more amps so 100 would be good( i cant think of a fuse inbetween). if this is what i am thinking you all are talking about. something about a fuse going to the battery from the alternator( or the other way around? i would talk to the electronics nerd( no offence to anyone) at the shop to see what they say.

and no sparky when i had one of these fuses it was 200 amp. but that went strait from my battery to my distribution block.

 

Thanks guys, it is working great! I just jumped #1 to BAT. It was putting out 14.27 volts on high idle.

Josh.