A few weeks ago I was overcharging at eighteen to nineteen volts and blew up my voltage regulator, making my truck stop charging. I replaced the voltage regulator and it started charging again, and the gauge said it was back in the safe charging range. However, I then realized my battery blew up and covered the entire underside of my hood with acid. The truck now has a new battery but also has a new looking alternator. I made some 2/0 battery cables and cleaned some grounds, along with putting a ground wire under screw holding in the voltage regulator. The truck is still charging at fifteen volts though. I think this is high because two batteries ago the case started leaking at fifteen volts. How can I get it to stop overcharging. I have tried but running some 10 awg wire from the battery to the engine but it did not change anything so I took it off. Any ideas?

 

I am not familar with these trucks so bear with me.
By the sounds of it you have a seperate volatge regulator, where is it picking up its sensing voltage? Battery, alternator or at a junction?
If it is seeing low voltage it will make the alternator charge.
The other thing is that voltage regulator maybe faulty, new does not always meean good.
Normal charge is around 14.7-15 volts, are you going just by the gauge in the truck or have you checked with a good multi-meter?
Ground cables can give you headaches as well, don't just check power cables for good connections, check the ground wiring as well.

 

From what I have found on firstgen.org, there is no reference voltage and the system is based purely on ground. They have said that to lower charging voltage you need to add grounds by adding one from the battery to the body and adding one to the engine. I added a ground and touched it to the engine but my radio shack multimeter told me 15v no matter where I put it. My plan is to try and stay persistent with this and try adding direct grounds from the battery to the voltage regulator and alternator, along with a ground to the body.

 

I was having that problem with my 90 ctd i have went through three of them all different brands i wish i could remember what brand i have on there but any way i finally got fed up with it and put a voltage regulator that has a dial on the back of it set my dial to 14.8 and its been good for four months now i used to blow through a volt. reg. every two to three weeks napa got pissed at all the waranties they were typing up and finally told me to get lost. If you do go with the dial option take a jumper cable and ground out the volt. regulator hook the regulator up and turn the dial (watching the voltmeter of course) set it to your desired voltage then shut the truck off put it back on the firewall hook it back up and you should be good. hope this helps

 

That sounds a little strange, all regulators have to have a voltage reference.
By chance do you have a wiring diagram? would need to see that to figure this one out.
This site may give you some ideas, MadElectrical.com - Electrical Tech.
Cheers Steve

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Tried putting your model truck and wiring diagrams in search. Got in once then was shutdown.
Where I am I have trouble with links and slow connections.
Go in and try seach, there are links to alternator troubles.
Cheers Steve

 

Thanks fluffy nuts. I am still going to trace my connections but I am going to try that adjustable regulator. Quick start is selling one that says it is by "transpo" for $34. Its at least a place to start.

 

it got to the point for me i was starting to blow light bulbs on top of my cab and i fried my headlight switch when i would have the high beams on i even replaced the battery in my truck after the problem got fixed it started to take the shape of a bowling ball from so many times overcharging im surprised i didnt blow my battery up cooked the hell out of it though. the guys at my local auto electric place where i bought the adjustable regulator said that the adjustables are the bees knees , that even a borg warner regulator couldnt even come close to the adjustable one think i paid like 50 or 60 bucks for mine but with price mark up u probably find a good one for 40 bucks any hoo good luck my diesel brotha let me know what u find out