[wilkin250r]

I agree with the above posts, in theory. If you connect both batteries in parallel, one bad cell can (and often will) kill both batteries.

However, I disagree in spirit. You run nearly the same risk with one battery. One bad cell, and you're stranded. One might argue that "twice as many cells means twice the risk", but is it REALLY all that risky? The vast majority of my batteries have died either from neglect, or just old age. Very rarely do I have a perfectly good battery just die on me from a bad cell.

So I'm taking a very small risk, and doubling it. Leaving me with... still a very small risk.