Thanks, but I couldn't find anything useful. The closest thing I found was:
but it wasn't helpful.
So, what do you think about connecting the internal battery contacts to another PE battery (bypassing the electronics), effectively letting electronics from one battery manage both.
It should just see it as one cell with double capacity, right? The only thing I can think of is if one of the cells starts loosing capacity, it would drag the other along. But since they are exactly the same batteries, it's probably not likely to happen.