Jump starting?????
 

When jumping someone else from my truck which battery should I use, left or right one. And what is the difference between the two batteries?

Which ever one is closer to the vehicle you are trying to start. They are both connected to each other. So, when you hook up to one, you are really pulling off of both of them.

I agree. Some will try to tell you it matters, but it doesnt

Doesn't matter which you use.

mis-understood question-- sorry