2004 ram w/ 5.7 hemi

Two weeks ago, my battery was always dead. After a boost or a charge, the voltmeter arrow was on the + side, showing it was charging, which is normal. I replaced the battery with a new one, but the voltmeter is showing the same level of charging.

Now I'm wondering if my last battery died as a result of constant overcharging (if that's even possible?). How do I check if the alternator is overcharging, or is there a regulator that might be messed up. My electrical knowledge is limited, but I can follow instructions well enough.


Edit: And the orange engine light is lit too. No change in performance, and when I checked for codes with the turnkey trick, nothing but 0000 came up. I found that strange.

 

Places like Autozone will test your alternator for you, but you have to remove it from the truck and take it in.

I have seen a lot of batteries come with a partial charge.

 

I agree, most batteries need charging when new, Auto Zone can tst both battery and alternator. You can measure the battery with the engine running and see if it is charging. Normal is somewhere between 12.8 to 14.2. The regulator is internal (PCM) and the charging is controlled by voltage, load and temperature. Good luck.

 

Turning the key for ignition codes doesnt work for 04. Get them scanned (if any) at Autozone when you go there.

 

Check voltage at the battery with the motor running. If the new battery wasn't so new, it might take longer to fully charge. That might produce voltage in the 16 range for a while. You could also put a trickle charger on it for a day or so.

 

Mike I think you have a problem The charging voltage should not be that high 14.8 on any system is about max. I would put a charger on the battery overnight and bring the battery to full charge and then test the system again. I would be comfortabe with no more than a 13.4 on a fully charged battery.l

 

you can take a multimeter and check the alternator while the truck is running and it should put out no mor than 14.5v and no less than 13.6v if it is you have an alternator issue

 

Thanks for your responses.

The voltmeter is still in the +. I measured with a multimeter:

12.5 V engine off
15.5 V running.

I will bring my alternator to the parts store and have them check it over as you have suggested.

Edit: Can this kind of consistent overcharging kill a battery's capacity for holding a charge?

 

If a 12v lead acid battery is overcharged, it will boil off the water from the electrolyte solution in the cells and release more hydrogen gas. When the electrolyte level drops too low, the plates will begin to sulfate with lead and the battery looses some of it's capacity. The battery will typically NOT recover even if you fill the cells up with distilled water again. This is why it's good to check the water level in the battery often and top it up.

The straight up answer is yes, you will eventually kill the battery if you overcharge it every time the truck is running. If you keep topping off the water in the cells, you will definitely extend the life of the battery even if you are overcharging it.

If your truck is overcharging the battery, the problem is most likely the computer (PCM) since most modern vehicles do not have a regulator in the alternator or even external to it. Go get the codes read at at AutoZone or somewhere similar.

I've heard of people adding an external regulator when the PCM won't regulate the voltage correctly, but you have to really understand what you are doing, and possible problems you may introduce. You are always better off replacing the PCM if that is the problem, but it might be possible that the PCM just needs to be re flashed by the dealer.