2006 dodge 3500
while hauling my horse trailer the other day (about an hour from home) the volt meter suddenly dropped down below twelve. I got the truck home, checked the batteries and the driver side battery was low on fluid so I put distilled water in as I've been told to do. The volts went back up for a few days and then dropped again back to below 12. Did I kill my battery?

I know I should take it to get it tested, but I don't know that I want to drive the truck in this condition and I can't reach up in there to pull the battery out (I'm really short) and the husband is gone for a few weeks.

Any and all advice welcome. I don't wanna kill my truck.

 

Hi Wingedmare,

The lifespan of a battery is officially about 3 years, in practice perhaps more like 5 but I’ve seen batteries go bad in as little as 2 years. No matter, if you have a factory battery in a 2006 truck its possible it’s going bad. But first I would check the battery connection, very often they get corroded (even if not visible) and the clamps need to be taken off and wire-brushed clean (1/2” plumbing brushes work good, both for post and clamp) and put back on tight.
Distilled water is fine, you only filled up to the fill mark correct? As long as the led plates are covered with acid I don’t think the battery a low level is causing your issue.
Did the truck sit for an extended period of time without use, or did you leave any electronics on for a while that might drain it? If the battery is discharged, it will need to be recharged by a good battery charger, the charging system in the truck won’t be ideal for restoring the battery back to a full charge.
Regarding testing, you can get a battery “hydrometer” from any automotive parts store for $5, they usually come in a dial or ball form but work on the same principal – testing the density of the sulfuric acid. Test the acid in each cell (hole), if they are all low the battery may just need a re-charge. If you find one cell low with the others near normal this is a sign of a bad cell, and you’ll need to replace the battery. But before you give up you should still try and charge the battery with a charger, then re-test and see if the cell’s perk back up.

All that said, is the truck having trouble starting or any other symptoms of a weak battery? 12 volts isn’t too bad, but I also want to make sure the voltage gauge isn’t just a little off. It should also read higher when the truck is running, as the alternator tries to charge the battery. After it dropped, did the voltage ever come back up?

-John
P.S. I’m not particularly short (5’ 9”) and I still need a step ladder to do anything under the hood of my diesel

 

what was the out side temp and how long was the engine running when this happened? it is possible you are seeing the grid heaters cycling and the will pull the voltage below 12 volts, if thats not the case i would have to say that the altinator may be failing, even with a toasted battery, most of the time the alt will keep it around normal voltage, unless the battery shorted internally which will normally take down the entire system

 

To answer questions: The temp outside both times was 100+ degrees (I live in the desert) first time it happened, I had driven 150 one way and was on the 150 mile return trip. Second time it happened, I drove about 5 miles to the grocery store and it dipped on the drive back. The truck is driven at least twice a week. And the batterys are only about a year old.
I am not really all that good at understanding the electrical system of my vehicles, so I didn't even think about the alternator. I dont' know if those answers to your questions give you a clearer idea of the possible issue. I am going to have to take her into the shop and don't want to be blind sided. I have to have her running tip top by friday to make another haul.

 

well, I got the alternator and batteries tested yesterday and the tests said they were all ok. am I looking at a volt regulatro issue?

 

the regulator is a nother possible problem, however the reglator is internal in the computer, you may start by tracing ground wires and checking for good connections on battery cables, body grounds, ect.