AA's vs Sub-C's ?

[BrianG]

Well, I did a little testing and I guess it answered my question.

I figured since I planned on using two AA cells in parallel to replace a single sub-C cell, that, for this test, I would halve the 30A discharge rating most places use to rate their GP3300 cells. So, I wired five 0.33 ohm resistors in parallel for a total of 0.066 ohms. This would draw an 18A load (provided the battery voltage stays at a constant 1.2v, but of course that won't happen). Once I hooked up the resistor pack across the AA cell, the battery voltage dropped to 0.84v. That equates to a 12.73A draw. Unloaded, the AA cell measured 1.364v. Assuming a linear internal resistance curve (which it's not), that equates to 0.041ohms of internal resistance.

A "zapped" sub-C cell supposedly maintains 1.17+ volts at a 30A draw. I can't imagine a non-zapped cell would drop much more than that (maybe 1.0v?) at a 30A draw. For this test to be conclusive, I'd have to try this test, except decrease the resistive load to 0.044 ohms (eight 0.33ohm resistors in parallel) to force a 30A draw, on a non-zapped GP3300 cell just to be sure. While I'm at it, I'd like to try this on a zapped cell as well to verify the claims. But, as I said before, I don't have the cells to test on. Poo.

If I had a GP3300 zapped, a GP3300 un-zapped, and equivalent zapped and un-zapped AA cells, I'd like to try the test again with incremental loads for a better test and feel for battery efficiency.