Batteries bad / both tops blew off on 1 battery
 

Just got back from Afghanistan. After being in storage for almost a year, I ended up having to replace both batteries, they were original. I bought 2 brand new top of line batteries, and the truck started right up and runs great. Well, after about 20 miles, I started smelling acid. So I pulled over and saw that both tops on the passenger side battery blew off and acid was everywhere. Luckily, I was able to clean it before the paint was ruined. So I went back to the store and got a replacement with no issues. But, the manager says that it's an overcharging issue and that the regulator inside in alternator could be bad and overcharing. My questions are 1: Has anyone had this happen and if so, what was the cause? 2: If the voltage regulator was bad, wouldn't both batteries get overcharged instead of just one? I personally think it was a bad battery, but I'm a little afraid to drive it now because I don't want to get straned somewhere. Thanks.

check what the alt is putting out.

1st check/clean all the grounds and connections between the batteries, especially the isolator down by the passenger battery.

Double check all connections to the batteries.
Check voltage while the engine is running and alternator charging. Shouldn't be more then 14.4 Volts.

Voltage is regulated by the ECM. Check all connections and ground points as mentioned.

The meter was right in the middle. I checked and rechecked, and the batteries were hooked up correctly. I've seen this before in an electric forklift. O nce the battery was replaced, no problems, that's why I think it's a battery problem, and not an overcharging issue. I've driven about 50 miles today with no issues. This is weird, I can't explain it.Thanks for your responses.

the battery could have been bad.

So I replaced the new battery, and within 5 minutes, both tops on the passenger side battery blew off again. I exchanged it again, so this is the third passenger side battery in 3 days. I took the alterator to both NAPA and Autozone to get tested, and everything tested out good at both places. So here's what I know: I have 2 brand new batteries, the alternator and voltage regulator tested good. All cables are in great condition. There are no check engine or gauge lights on, so I'm stumped at this point. I appreciate any responses.

Carry some baking soda with you to neutralize the acid. :ouch: My initial thought is to switch the driver side battery (which has been good the entire time correct?) with the passenger, to make sure hte issue is isolated to the passenger side, since you know for certain the driver side battery is good. But then again, that will probably cost you another battery as well.

Yes, the driver's side battery has been fine all along. I did think about swapping sides as well, but chose not to. I think tomorrow, I'll go talk to the service dept at the local Dodge dealership. I'm afraid to drive it in case it does this again in traffic. Whatever it is, it is isolated to the right side. I am thinking about just replacing all the battery cables just to eliminate that, but I don't see why they would go bad. Nothing's happened to the truck, it was just sitting for 11 1/2 months, and I did disconnect the batteries and taped the terminals before I left. I wasn't surprised they died because they were the original batteries.

Did you look at the isolator? A failed isolator or bad connection/broken wire to it is what typically causes your problem.

Yes, there are no broken wires. I took a multimeter to all cables and fusable links, everything's good. Other than the PCM going out, which is about $2000 for a new one at the dealership, which by the way I was told that those are V.I.N. # specific, I'm thinking that although the voltage regulator tested out okay, it might be stuck so that's it's constantly charging. So I guess I'll buy a new alternator and go from there.

The only way the alternator would be a problem is if it was not charging. At this point I would be taking it to a dealer and get it properly diagnosed, codes pulled, etc.

So I ordered a new alternator from the dealership, if this doesn't fix it, I will take it in, I'm just afraid to drive it because I don't acid going everywhere while I'm driving it with no way to clean the paint of it happens in traffic. By the way NadirPoint, thanks for your responses, and that's a nice looking old Dodge you got there.

Thanks, I like it alot, they don't make them like that anymore, or so they say.

If the dealer is not too far away you could try disconnecting the alternator and driving it over there on just the batteries to avoid any charging issues.

Have you checked the voltage at the battery terminals seperately while running? It bet one says a few volts higher than the other.

check the tone ring on the crankshaft, if one of the tabs is broken off it will cause the computer to over charge the passenger side battery. I boiled 2 battery because of this. i had dodge change the tone ring and had no problem since. hope this helps:humm:

I have never heard of a tone ring. I will definately look into that. I did put a new Mopar alternator on today, and it sure did happen again within minutes. I'm trying to keep this at a minimum, so I'm trying to troubleshoot based on the cheapest senario. Right now, I'm at $575.00 for two batteries and an alternator. I'm going to Texas tommorrow. so this will be on the back burner for 30 days, but I will still look into this,Thanks to everyone for all of the responses.

tone ring
 

Not sure why my reply didn't get posted, but the tone ring is on the crank shaft behind the pulley and the harmonic balancer. not sure why it over charges the left battery, something to do with the computer not reading the rpm right, but i took it to the dealer and that is what they said and it fixed the problem for me. oh they all so change the sensor reading the tone ring. hope this helps

Yup the charging system is reading low voltage and full charge is going into the pass battery definitely what Nadirpoint said is the problem!

I took it to the dealer, and the problem was that the ECM needed to be flashed. It was corrected in about 30 minutes, much cheaper than what I was expecting.