[Emergency + UTC] Battery does not last long!

[jsmo]

Greetings!

I have a Breitling Emergency with UTC, use it every day since 2010. Had to change the battery, a friend (working in this field) did it. I mean the watch battery, not the transmitter batteries.

The new watch battery stopped working after about 3 weeks. Well, we thought the battery was corrupted, it can happen.

Second time, same thing.

Third time, same thing.

Batteries are V399 Casio, bought in reputable place.

The transmitter itself works, we didn't even check the batteries as the tester sends the good signal when we checked.

The nearest Breitling service is about 6000 km away :) So, any suggestion?

Thank you!