6.7 cummins alterner charge surge2

[xgiovannix12]

hello everyone i have a 2013 ram 3500 with the 6.7. I notice when its cold and on the 1st start that my alternator will surge between 12 to 14 back and forth till warm. Is this normal? Only had the truck for a month or 2 and it really dont sound normal to me. Going to start by having the batterys tested

 

[crash68]

I'm guessing the voltage fluctuating is from the grid heater cycling on and off. Elevate the idle and see if the fluctuations stop or are not as bad. Getting the batteries tested is a good idea, this fluctuation could be showing a cell or two are going bad. If that's the case, you have to replace both batteries at the same time.

 

[huntergreen]

Agree with above, esp if your running the stock batteries.

 

[tjfdesmo]

Grid heater, for sure, all normal.