Batteries in a diesel

I have a 94 and a 06 Dodge diesel trucks, do they really need two batteries? I can get 900 cca 3 year battery from WalMart. Opinions?

Go ahead, give it a shot. Then report back with your results.

Go ahead and take that new 900 CCA Walmart battery to a real parts store (not O'Rielys, Advance, Pep Boys, etc.) and have it tested. Then compare it to one of their new batteries of the same group size. The difference will be shocking. We've had several Walmart technicians get batteries from us because they refuse to buy a battery from the place they work.