Thanks... 1. We can use both sides of battery to put the foil (or i'm wrong ?) In this case we have only one cross of foils that can be isolated with small patch of something.. 2. About bad connection of foil, I will check when I will get my new battery.
Hmmm, I have another little question. I still afraid a little bit about heating of the foil, maybe it better to put something (2 strips of isolation band) between battery and the foil ? What you think ?