450 C charging/starting issues

[atbrdly]

I have owned the 450C for about 12 years. Always had a single wire alternator. The last year or so the charging/starting gremlins have reared their head. At first i thought it was the battery. replaced the battery. then i thought it was the alternator, replaced it twice. still having issues. go to start the dozer even after having it running and it doesn't have enough power to crank.

The first alternator was bought by my brother who talked to a guy at the local truck shop who "said it would work as single wire" I wasn't confident in this but put it on anyway. still the same problem. hardly any voltage measured at the alternator. Thinking it was NOT a single wire alternator, i bought another one at NAPA that was for a single wire application. The current alternator i have on it is a NAPA 213-4011SW (suppose to work in single wire application).

I've done some testing around on the dozer.

Battery at 12.5 volts (took out and charged with battery charger)
Starter at 12.5 volts
the single wire going to the alternator unhooked from the alternator was testing around 10.5 volts (weird but not the reason alternator is not putting out voltage i wouldn't think.)
Alternator output max was around 4 volts. This was at high idle.
Thinking it may be a grounding issue we hooked ground cable from alternator to battery ground. NO change in voltage.

I am unfamiliar with how a single wire alternator works. Does it only call for voltage when the battery needs it? Why would the stud on the alternator not give 14 volts?

Surely two different alternators wouldn't be bad, correct?

The belt is tight and the alternator seems to be functioning correctly.


Voltmeter on dozer doesn't work. I thought about re-wiring the entire starting/charging circuit but i need to understand why I'm not getting 14v out of the alternator before re-wiring.

****Just as an FYI....with the charged the battery, the dozer has no trouble starting

Please help. THANKS

[Jim B]

I had this all typed on the Early Models Board as you just as you made your latest post there. You can use the edit feature and delete the text and replace it with something like Moved to Late Models Board.

The battery voltage is low and would be since the alternator is not charging. A properly working alternator will show 14 to 15 volts when running with a fully charged battery in the system. The regulator is inside the one wire alternator.

You say the voltmeter on the crawler is not working. The 450C had an ammeter originally, if you in fact have a voltmeter, that tells me there have been wiring modifications as a voltmeter cannot be connected to the wires used by the original ammeter. Current from the charging system or load draws do not pass through a voltmeter, current actually passes through an ammeter. A voltmeter needs a power wire from a switched source on one terminal and a ground wire on the other. An ammeter is live all the time with current going both ways through it. You need to figure out what was changed to install the voltmeter, there could be a problem in that area.

You should have battery voltage or within a couple tenths of a volt of battery voltage at the alternator stud. That should be with the wire hooked or unhooked with the engine and key off.

Running an alternator without it wired, up or lifting a battery cable when one is running, can damage the electrical system or damage the alternator as alternators can spike high voltage. They are not like generators that could be run or tested without a battery.

I don't have a 450C wiring diagram, do you have the Technical Manual TM1102 which has the wiring diagrams so you can check things?

The original alternator was a Motorola with an external regulator. The same output wire could be used with a Delco type one wire alternator, if the ammeter was still there, or if it was properly bypassed. The external regulator and related wiring should have been removed.

Where is the other end of the one wire on the alternator connected? I would expect it originally went to one of the ammeter terminals (with all the load wires) and a wire from the other ammeter terminal to the battery cable terminal of the solenoid, possibly there would be a circuit breaker in that wire.

Are all battery connections clean and bright? Clean and tighten the other ends of the battery cables. You may have a bad wire or connection somewhere. A voltmeter will give a reading of voltage on a wire that won't carry current enough to operate properly. Make a test light using jumper wires and a 7" round headlight to use along with your voltmeter. Those seal beams draw enough that they can sometimes show a weak circuit. with the seal beam in series to ground. Use your voltmeter to check how much the voltage drops when the seal beam is on compared to what it was without the seal beam on.

Not common, but it is possible to get more than one bad alternator.

[atbrdly]

You are correct. it is an amp meter on the dash that doesn't work. I do have the Tech manual but, as you called out, it is with the old motorola and wiring. I got confused by it and relating it to my one wire system.

I have not dug into where the wire from the alternator is going yet. it goes into a wire loom and i guess that should be my next step.

the battery cables are all brand new.

However, the wiring behind the dash has seen better days. it needs attention. I think it would be just as easy to re-wire all of it. I just wasn't sure to put my effort there yet due to the fact that I wasn't getting anything from the alternator in the first place.

If i were to re-wire, would the below wiring work? I don't have the ammeter in there. i could buy a new one and add.

Battery to Battery terminal on starter solenoid
Battery terminal on starter solenoid to Battery on Key switch
Battery terminal on starter solenoid to Alternator
Ign/Run from Key switch to Fuel Shutoff
Ign/Run from Key switch to Push Button
Push Button to Neutral Safety Switch
Neutral Safety Switch to "S" terminal on starter solenoid

Thanks for the help. I have some more investigation to do

[Jim B]

I say use the wiring diagram and do it right. If you have the manual with the wiring diagrams it is not hard to sit down with the diagrams, figure out and remove the wiring the Motorola charging system had and insert the one wire needed for a Delco type one wire alternator, which basically is just the output wire on the Motorola drawing. Then use the reworked diagram to do it right.

Now, saying you have an ammeter, not a voltmeter, the fact that it is not working is the starting point. If it has failed open and current can't flow through it that could be the problem.

There is the chance you have damaged the alternator running it against the bad wiring. or it was defective. Can Napa test it or is there a shop near you that can test it to be sure it is working? That means actually hook it up on a test bench and spin it to check it?

[Stan Disbrow]

Hi,

A one-wire alternator has all the electronic parts of the regulation circuit within, including the cutout function. All you need to do is run a wire from the one (and only) terminal on the unit to the positive post of the battery. See if it raises the battery voltage then.

It needs battery voltage present on that terminal to work. Alternators do not have permanent magnets within to self-exicte. So, I suspect the original machine wiring is not connecting the battery to the alrenator.'

Hopefully, no one decided to hook the one-wire alternator to the battery thru the ignition switch. Opening that connection with the alternator outputting will, as already noted, spike high voltage inside the alternator and fry the internal regulation circuit.

Stan

[atbrdly]

Stan,

Thanks for the information. Can i simply run the one wire from the one and only terminal on the alternator to the battery terminal on the starter solenoid? Same as going to the battery itself?

[Jim B]

Yes, you can run a wire from the alternator to the starter solenoid. Without it going through a working ammeter you will not have any "on-board" indication of whether or not it is charging.

Can you scan or take a good quality picture(s) of the wiring diagram(s) in your TM1102 manual? If you can and want to do that, I will modify the drawing(s) to remove the Motorola alternator and regulator. I will replace the Motorola equipment with a Delco type one wire in the system for you. Then you will be able to use the diagram for troubleshooting in the future. If you want to take my offer, let me Know when you have the info to send and I will PM you an email address to use to send them to me.