Battery overheating

[Clarkrj]

I have a problem with a battery overheating on my 01 Chevy C/C Dmax. It all started last year in july when my alternator and both batteries went out according to Mr. Napa guy so I changed everything out. Well, This past weekend I popedd the hood open and the same battery station was hissing and seemed to be overheating again. I took it down to the Napa guy and of course he says his stuff is fine and I have a wiring problem. The alternator is putting out 14.4 V. Has anyone had this problem and what was the culprit? Thanks in advance. Ronny

[VA_Dmax]

I thought it was normal for an alternator to put out around 14 volts. I dont think that is causing the battery problems if that is what you were asking.

[DmaxMaverick]

Welcome to the forums Ronny!

Early on, there was a computer update for the 2001's to address erratic voltage regulation. Perhaps you are seeing the long term effects of the original issue. If you have not had your PCM updated, you should. Other than that, I don't have an answer. The alternator output is controlled by the PCM, not a "voltage regulator" like previous vehicles. Because you have changed out mechanical devices, the only things left are the controller (PCM), sensor, wiring, or a bad ground somewhere. Mismatched batteries have caused similar problems on older models.

Is it both batteries, or just one? If only one, it shouldn't be too difficult to chase down.

[madmatt]

no bulletins on this nor have I seen this. I'd start by checking alt amp output and check the amp draw from the effected battery both KOER and KOEO. also if the NAPA guy didn't, i'd test that battery. it may have shorted. which battery is having problems. if your alt isn't shutting off correctly, it could "cook" your battery. when you have this problem, do you also have starting problems????no start, no crank, absolutly nothing, etc.... Any high powered accessories????

[jbplock]

In addition to previous posts, if one battery is not charging it may cause the second battery to overcharge. Good practice is to always replace batteries in pairs to keep the load on the alternator balanced. A poor connection on one of the batteries could also contribute to the problem.

[Clarkrj]

Thanks for the replys guys. Now I will answer your questions. The NAPA guy did check both batteries and the alternator and said all was fine. I may have a PCM problem. Hopefully need an update. The truck starts fine,runs fine,shuts down fine. The battery that is overheating is the one nearest the passenger side firewall. The other battery is fine. No signs of overheating.I really want to get this fixed so I can clean up the mess from the acid fumes. The battery tray is nice and rusty. Thanks in advance guys. Ronny

[madmatt]

if you don't find any charging problems keep in mind that the pass. battery only powers accesories and your drivers handles the starting duties.

[DmaxMaverick]

Originally posted by madmatt:
if you don't find any charging problems keep in mind that the pass. battery only powers accesories and your drivers handles the starting duties. Maybe true for the gassers with dual batteries, but not GM Diesels. Ever. They have always been wired in parallel, with no isolator. It's been that way since GM's first Diesel, and is that way with all Duramax Diesel equipped vehicles.


That being said....
If you have one battery overheating, and the other not, the problem is with a poor wire connection, or bad battery(ies). The PCM or alternator doesn't know there are 2 batteries. There is a single cable connecting the passenger side battery to the starter solenoid, and the batteries are wired in parallel. No way can one battery get more charge than the other, with the exception of the current loss due to the length of the cables. I suspect your driver side battery has a poor connection somewhere, either the ground, or crossover cable. If all connections are good, you have a bad battery.

[madmatt]

dam it, you caught me before I did! Sorry for the confusion, I had a massive flashback of just the other day when I had to re-wire a dual battery system....then after reading Mav's post I realized it was a 6.0L. I got so caught up in the wiring, I didn't think w/ engine was in it. Some shadetree put in new batteries and cables and got a positive cable under his pass. battery. A week later it nearly went up in flames. It was a nightmare! I should have know better, cuz just a week or two ago I replaced a pass. side batt. for a no start in a d-max.

[Clarkrj]

Well, I took the truck to the chevrolet dealership and they found nothing. They said they checked the charging system and all the wiring. So what is the next step. I still feel there is a wire or connection causing this but how do I find it nobody knows....

[copperhead]

Swap the batteries, see if the problem moves, if it does, bad battery, if it doesn't there is either something in that location applying heat to the battery or your back to a wiring issue of some sort.

[mdrag]

I had a battery issue after an aftermarket alarm install in my '01. It turns out that the ground terminal bolt was replaced with a slightly longer one, and even thought the bolt was tight, the cable was still loose since the bolt bottomed out in the hole. This caused an intermittent connection and all types of wierd electrical problems. I must have checked a dozen times before finally finding the problem... Good luck.