Someone brought up a good point about two cells not being equal to each other. I've got two identical cells connected in parallel. But I can see that, as they age, one might retain more capacity than the other, and consequently the good cell might try to 'charge' the bad cell.

This may seem like over-simplification, but a diode (of the correct size) would solve this problem. Has this been tried? Are there any off-the-shelf gadgets that already do this?

Thanks,

Bob