What is correct charging voltage

[DougW]

My 07 CTD 2500 charges at 15 volts as noted on my dash gage and two seperate Fluke meters. Isn't this a bit high, I'm thinking 13. 8 V might be a better max charge rate? What does Mopar say? Wouldn't this high a voltage tend to cook the batteries?

 

[JHMiller]

Yes, 15v is a bit high. 14. 4v is normally the appropriate voltage for fast charge. Check out Progressive Dyn Inc. Google on Battery Management 101 and you'll find the site. It's aimed at RV and Marine but all lead acid batteries require the same charge rates as each cell puts out 2. 1 volts fully charged for 12. 6v fully charged, 12. 1v 50% discharged and 10. 5v fully discharged. I'm not sure if the truck charge system will raise the voltage to 15v to overcome sulfation or poor connections. I maintained Flukes for years and if you have 2 reading the same, your good to go. Over voltage will warp plates causing premature failure. Check the battery sides and ends for bulging, a sign it's being cooked. Walmart sells inexpensive "smart chargers" that do the equilization charge to break up sulfation. As you know the truck charge system is really engineered to keep the batteries charged... . John

 

[ENafziger]

Mine has always charged at 14. 9 - 15. 4 volts. This is with a digital meter, monitored continuously while driving over the past years.

--Eric