charge light won't go out

[ggzilla]

Glad to hear the CHG light finally went off

 

 

But when did this start happening?

That volt meter is jumping rope

Sound to me like a bad voltage regulator -- or more liklely a loose connection somewhere. In 2007, I drove my Datsun from LA to seattle with the big wire on the alternator not even bolted on. But I never lost power, battery stayed charged.

[wayno]

I have had a battery boil because the amp gauge was pegged as the alternator was overcharging, this was caused because a wire came loose between the voltage regulator and the alternator, the alt. was putting out max all the time till the battery was wasted, I didn't smell it till I came to a stop, the top was down on the roadster.

This is what it was pumping out, not overcharging in my opinion.

I am so happy that I wired that gauge correct the first time, I usually get it backwards and have to switch the wires. :D

I do beleave I am going to have to do something soon about the wiring in this truck, I was hoping to put it off till I had the time to make another kingcab/double cab for this truck, and drop it onto a 720 frame and use a 720 wiring harness.

[ggzilla]

Yep, if the Voltage goes up, so will the current (amps). That's why a voltmeter is somewhat better than an ammeter, it will warn of both problems. Ammeter won't tell you if voltage is too low or too high. Amps can be normal and still overcharge a battery.

[wayno]

I was hoping to have an answer by now on my 521 thread, but no responces, so I will try here.

 

 

Posted Yesterday, 05:44 PM

I put another alternator in the truck, it does the same thing as the other one did before it went bad, the volt gauge in the cab jumps between 12 volts and 13.5 volts like it is going threw a flasher unit, there has to be a reason for this jumping, maybe in the wiring harness of the vehicle this internally regulated alternator came out of, there is something that I don't have in mine.

 

I went and talked to Ryan at the auto parts store, he suggested that maybe the exciter wire going to the back of the alternator should not be 12 volts, does this sound like something that could cause my issue, is that wire supposed to have less voltage going to it, could this make the volt meter jump around?

 

My alternator is wired very simply now, the main output goes directly to the battery, the exciter wire goes directly to a key initiated fuse box post, the light wire goes to the dash light, which I removed while running to see if that was causing the issue, it changed nothing when disconnected, and the alternator is grounded with two ground wires, the original, and an extra I added.

 

I really need help to figure this out, as I don't understand this issue, it acts like the charging is turning on and off, like it is going threw a flasher, and the dash light very dimly does the same thing, it kinda turns on and off.

[ggzilla]

Since when do guys at the parts store know anything :-)

 

What is an "exciter" wire -- this is not a generator. The four wires for an IR alternator are BAT, GROUND, Sense (BAT) and L (Lamp).

 

 

> the volt gauge in the cab jumps between 12 volts and 13.5 volts

 

Have you tested the volt gauge? For example, tried it in another vehicle, or tried running two new wires straight from the battery to the gauge?

 

Start with the problem, not the solutions. The problem is your volt gauge is jumping around.

[wayno]

The guy at the parts store is a member on here, he was the one with the swamp cooler on his 521 at the last canby meet/show.

 

The volt gauge did not jump around like that with the internally regulated alternator that was on it before, so I guess that is not the issue, as it worked fine since august 2011, it only shows the battery voltage as I just connected it to a 12 volt source at the 521 fuse block...............wait a minute................I walk away from the computer......................

 

Ok ggzilla, you made me think about how I had things hooked up at the fuse block, the fact is I have had several things I have used in my truck over the years, one is a dual battery isolater for 2 batteries under the flatbed of the truck, I removed these batteries several years ago as I didn't need them anymore, but the isolator remained connected, as I have been going threw so many starters lately, I have been removing everything possible wiring wise to isolate the starter from outside sources that could cause any issues, so I removed the main cables that went from the starter to the isolator to charge the rear batteries and the main battery, but there was one wire I did not remove, and it was connected the same place the volt meter gauge wire was connected, the exciter/activator wire that makes the the dual battery isolator work was the issue, since it was activated with power from the key, it would try to charge something that was not there anymore, so I just removed that wire from the fuse block, and now I have 13.5 to 14 volts steady.

 

Thankyou for making me think about the fuse block and how things were connected, as far as I was concerned, this isolator was dormant, as the main battery cables were no longer connected, but that one activator wire was still connected and freaking everything out, thankyou again ggzilla, and this is why I ask on here.

 

wayno