Ok.... Today I finally received my battery and 20 min ago I finished the work
I didn't used glue (still didn't get it). Just banded the foil and added another little strip of foil over this to hold it on the place.
For now all work, will see tomorrow on heavy usage and usage + charging with portable charger... Some pics:

Continue....

Continue again....

And from the test...

Well done, neat job!

Hi! I have done it with the same battery and foil. But unfortunately it does not work. The charge status say always 50% and after plugin a charger I got "Leider hat das Laden nicht funktioniert. Versuche es mit einem anderen Ladegerät" Tomorrow I will try another test...

One of your contacts is dodgy. Did you fold the end of the foil over the original contacts as per post 25? And did you either solder them or at least used a conductive glue like Schturman?

I forgot to add the last pic... Because this new battery a little bit small I added small pieces of paper to prevent moving of battery (also press the foil on orig contacts) and unexpected reboots like I got in the first day of usage...

I used the second solution with foil and without glue. After trying it a third time and adding some rolls of foil over the contacts to get a better contact between foil and battery connections it looks like it work. I think these ball do the same like the paper in Schturman last post.

I hope it will working also tomorrow Now I can wait relaxed for Sailfish on Sony Xperia X...

Thanks a lot for your solutions and al the pictures!

Cheers,

Attached pics of revision 2.1. Performance has improved noticeably, especially measurement accuracy. Lately I was experiencing sudden charge drops, meaning probably that the battery was aging, although having been in use for just about 6 months that looks a bit strange to me.