If you have dead batteries, does it matter which one you hook up to to jump start it? The last time I did this I jumped on the driver side and it started right up. This morning I first tried on the passenger side and it wouldn't start. I swithed over to the driver side and still no start. But one thing that was strange was that when I turned the key back to the off position the headlights came on and went off. Never seen that before.
I think the batteries are just really drained this time, hence the no start.(It did barely crank) It hasn't been driven in 7 days and I left my CB on.

 

IIRC you always want to try to jump the primary, which will be your driver's side.

 

Maybe I'm mistaken, but I thought that Dodge hard wired them in parallel without any passive or active isolation circuitry.

(I don't think there is any difference in which battery is primary.)

 

They are parallel, however, the way that it's always been explained to me is the the driver's side was the primary and the pass side was considered the secondary. The reason for this is that the driver's side is the closest to all of the electrical components (fuse block, starter, etc) You want to jump from that side because there is less current loss then there would be from the pass side.

Like I said, that's how it's always been explained to me and the theory sounded true so I've always ran with it.

I could be way off.

 

I had a post about batteries and jump starting before. And I'm still not sure what is correct. Here is the thread https://www.dieselbombers.com/cummin...-starting.html

 

Thanks Jazz, I read all of that. And now that all of this is clear as mud, I'll add to it. Since the batteries are in series, when you put a charger on the what appears to be the primary, does it charge both batteries or only the one battery. My thinking is that it charges both.
I have a new charger on the truck now and for the amount of time it is taking, I really think it charges both.

Anybody have any ideas or thoughts?

 

Charges both!!

 

your driver side is your primary battery, but they are wired in series with only one common ground which makes it a 12v system if it were wired in parralel it would be a 24v system IIRC. But it does make a difference on which battery you charge i always do mine on the driver side and it works good.

yeah it does charge both but ive been told it pulls more off of the driver side battery during starting

 

Would it make sence to unhook the primary batt. when jump starting to keep it from robbing current?

 

you mean hooking the jumpers right up to the battery cables??

you could but i dont think it really matters once you hook the jumper cables to them its hooked to the cables anyhow and the battery shouldnt rob that much power from it.