62 charging issues (1 Viewer)

[dd113]

My main 62 has always been a bit low on charging. The output on the alt usually is just below the mid line on the gauge or 10ish volts at idle. When it would go up to 1500 RPM or so I would hit 13-14 volts. That is normal from what I have seen on them with older alternators. I have had 2 used alternators on it with the same results more or less.

The current alternator just crapped out. It happened to crap out right after I set up the dual batts. The dual batt set up is correct and even if I isolate the primary batt it is still a dead alternator.

I bought a NAPA reman and installed it. More or less it had low output no matter if both batts were hooked or not. It would not charge at all once I started the truck until I got it above 2500RPM then it would kick in and work but it would not read more than 12V no matter the load or the RPM.

I pulled a known good OEM alt off my other 62. On the other truck it read 13.8V at idle and 14.4 at 1500 which is good/normal. Under load it would fluctuate a bit then stabilize back at the proper voltage.

I installed it on the other 62 and got almost exactly the same results as with the rebuilt NAPA alt. 10 V or so at idle. Gets up around 12V at 2500 RPM or better. It never will go over 12.5 volts no matter the load.

All this is telling me there is an outside issue from the alt. All wireing is new or checked, batt leads are custom and test out perfect. The charge light does not come on ever. Could this cause a low charging condition? I read the diagram and did not see how it could but? If the charge relay is out would that cause the issue?

Bascially I have low charging no matter what alt I use? WHat other issues can there be?

 

[Landpimp]

charge light does not even come on when you turn the key to run but don't start?

I suspect a bad cable, prolly a ground. After I re cabled all the grounds and pos on my fj60 the alt hardly dips anymore.

how about a fusible link? bypass them and see what happens.

Are you reading the volts off the batt or the alt?

not sure, just tossing some stuff out

 

[Poser]

You are on the right track with your thought John..

 

[yooper]

I strongly agree. Replace all the ground cables and the cable from alt to battery and the fusible links. There are a lot of ground cables - get 'em all.

 

[dd113]

Good thoughts

Batt to ground is good. Motor to body is good, starter to frame is good. Am I missing some grounds or is that it?

New POS cables all around using 2/0, same with main ground. New terminals.

All new connections on the POS post from the harness. Fuseable link must be OK as the truck runs and starts fine and has never had a bad batt voltage no start issue. It may not charge well but it does charge.

On the same note; the IG wire comming off the alt is the BW or BY (cant remember which) The instructions on the isolator said the IG wire should only have current at run or start. In neither setting do I have current. WTF? Is that correct?

 

[Landpimp]

should be another ground, its right by the battery and conects to the body then goes down to under the AC comp, but you might have covered this one. I understand that both pos and neg should be the same size cable, so if 2/0 pos, then 2/0 neg......however I don't have proof this is true?

My gounds were good......but when replaced.....became ALOT better

I don't know crap about isolators, I use selnoids for the dual batts, much simpler. Dont issolators have loose some voltage? maybe as much as 1 volt?

did it have issue before the dual batts?

I have had fusilbe links that were only sorta bad.

 

[dd113]

Isolaters might lose a bit but it would not explain this drop and it happened prior to the dual batts install.

I made all my own cables within the last 12 months and you are right I did forget about the one from the batt to the AC mount but I did it.

I saw your solinoid set up and really liked it. My isolater set up is just about as easy but cheaper. It might not be as good though ??? I will check out the fuseable links as you mentioned. I have not seen ne 1/2 bad but it could happen.

I feel like I am missing one thing in here. I will find it eventually or I wil carry a bunch of batteries out to the LSRU

 

[dd113]

FOund it!

There is a small bolt/nut connection in line with the W cable comming back from the alt B+ post. This charges the batt adn sends current to the 'always on" items such as dome light, key left in ignigtion bell etc...I had tested this out and cleaned and resealed it but to do so I had to pull it out. When I stuffed it back down in there it would somtimes short or disconnect at the terminal causing a bad charging situation.

Big PITA to find.

 

[Landpimp]

the nut bolt thing is where the fusible link(s) hooks up before it goes to the battery, right? in the hard plastic housing?

glad ya got it

[quote author=dd113 link=board=1;threadid=12156;start=msg111984#msg111984 date=1077937774]
FOund it!

There is a small bolt/nut connection in line with the W cable comming back from the alt B+ post. This charges the batt adn sends current to the 'always on" items such as dome light, key left in ignigtion bell etc...I had tested this out and cleaned and resealed it but to do so I had to pull it out. When I stuffed it back down in there it would somtimes short or disconnect at the terminal causing a bad charging situation.

Big PITA to find.
[/quote]

 

[dd113]

it is 8 or 10 G on one side and 6-8 gauge fuseable on the batt side. It all still tests out OK. The issue was in the terminal on the harness side. It could move around a bit loseing contact and loseing charge at the same time. It would only do this when it was bent a wierd way. No way to find this than hunt and pick

 

[Poser]

Congrats!

I have pulled my hair out many a time chasing sparks...

 

[yooper]

Strong work DD, and thanks for the update. I'll keep that one in the back of my brain for when it happens to me...