i have been using a snap-on "alternator starting and charging systems tester".it checks about everything you want.

 

Does the fluctuation increase with the RPM's, this could be bad diodes, 1 phase out will cause a fluctuation.

Have you load tested with a carbon pile on the battery yet?

 

Which model?

Do you have the manual for the tester? I woud be interested in how it describes the expected result of a normal alternator based on how you hooked it up.

 

work with me on this.i have very little electrical knowledge. that is why i need your help.JIM LANE-, yes, the fluctuation increases with the rpms.i did not load test the battery.i just switched batterys.same thing with both batterys.i use a group 31 battery.i took the alternator to an alternator shop to have it bench tested.i wonder if the bench test that gave me good results is in fact wrong! i'm thinking a bad diode may be the problem.could it bench test ok,but act up on the truck (vibration of engine)? CLASS A4x4-the tester: you clamp the two heavy wires on the battery.then i clamped the induction probe ( i guess tha is what it's called) over the large (hot) wire running from the alternator to the battery.the tester has a digital amp and volt meter.it also has a rheostat to load test the alternator. it's a common style most everyone uses.it's not some elaborate scientific machine. i really appreciate the time and help you are giving me.

 

A one wire alternator is a step backwards from any stock system with remote sensing.

 

My 1 wire alternator has worked flawlessly for years now but it does make for a primitive charging system, I want to upgrade mine to a Balmer Multi Stage Regulator, this way I can properly charge all of my batteries.

http://www.defender.com/product.jsp?...1713&id=711619

Todays batteries all have different parameters for charging.

You need to find out why and fix the problem before you make any upgrades.

One phase out or low will show a pulse every revolution, the more current produced, the higher the detected pulse will be, all alternators "Bat" terminal will pulse some until the battery is connected to smoothen them out.

I can detect an ac frequency on mine.

You can check your alternator diodes and stator windings with an ohmmeter.

Is it still the stock 120 amp Nippon-Denso?

Jim

 

well,after many posts and a lot of great help,i think i'm going to go with a single wire alternator. i'm not sure if i should go with a delco 22si or a delco 24si ? i think a 28si would be overkill for me (giong to stick with delco for price and availability).our local alternator shop stocks all three.they also have an assortment of 8 groove pulleys. i don't need anything to big as i have no acccessories. what do you guys think on alternator choices? JIM,yes it's a stock nippon-denso.i think you are right on the doide.i wasn't there when they bench tested my alternator.i just think something went wrong there.also i never could find that shunt wire between the amp gauge wires.but i doubt that has anything to do with my problem.that's about the only wire i couldn't trace.

 

1. That is one of the items I specifically mentioned would cause your symptoms.
2. There are very specific reasons why a 1 wire alternator would be a downgrade.
3. I don't think anybody here thinks your alternator is bad.

 

J MARTIN,i remember you saying about the shunt wire..i just couldn't find it in the loom. but i found both amp gauge wires on the outside of the firewall at the big connector and unhooked them. still had fluctuation with them unhooked.i think that should have isolated the shunt? i also ran a jumper wire from the alternator to the battery and still the same fluctuation with the jumper.help me out here,why do you think a one wire alternator is a down grade?

 

If you're talking about the alternator current, as read by your tester, jumping around a bit, that would be normal. A regulator switches the field on and off, as that doesn't heat up the regulator circuitry as much as a steady current to the field would. They were pretty primitive in the electronics department back then

The shunt is connected between the two ammeter wires. It may look like a solid block of metal, or a short piece of heavy wire. I don't know how that one is hooked up, just know the electronic principle involved.

If the alternator is high output, there can be significant voltage drop between the alternator and the load unless it's wired with extremely heavy wire. 120 amps through 6 gauge, for instance, can drop a half volt or so. If the sense wire for the regulator is on the load side of that wire, it's not a problem. If the sense in on the alternator side (1 wire) then there can be a problem with undercharging.

If a test setup runs the alternator at varying outputs and it's steady, then it's good. The load is varying. If you suspect diodes, have the tester set up for 24V. A good alternator will do it without harm. If there's a weak diode, it'll smoke.

hope it helps

 

fixed my problem! delco22si.