A nickel battery for my Sennheiser wireless!

A nickel battery replace those of my Sennheiser RS85 whose capacity had a much diminished with time (within 2 hours) and the other had passed away long ago. This battery has two decisive advantages:
- Its price almost four times cheaper than battery sold under the brand Sennheiser
- Autonomy of at least 6 hours, probably more. In any case more than enough for I am not come to the end in one evening (the 2nd battery becomes useless). On paper, its capacity to new state is 3 times higher than the original (190 mAh against 60 for the original), so in theory, autonomy too.
One unknown: the evolution of its autonomy over time.