Need Help with L4 and Pilas!

Hey guys I have a question. I just got 2 L4s from a forum member and they're great, but one of the KL4 heads doesn't want to run on one of my Pila 168s batteries for some reason. I have 2 168s batteries, they're both only about a month old and have only been used a few times each. I've tried this head with the other rechargable and it works fine, it works fine on SF123s, but for some reason, it doesn't want to run on this specific Pila--I even tried different tailcaps. Does anyone know what the problem is? Is it the battery or the KL4? Thanks /ubbthreads/images/graemlins/help.gif

Tried foil under the + on the head? Just to see if one Pila is shorter than the other.

-LT

Look here.
My L4 won't run off one of my Pilas-whose + end is pushed in a bit, or either of my 17670s-which are flat on the + end, without something to help make contact, and these magnets work perfectly.

Thanks alot