well so far - durability has to prove himself

Does the battery is not too large, etc.
Only the cable is a few millimeters too short, but incorporated in a different position it works nonetheless. (Nüvi 650)
The first shop took a long time, so the capacity seems to be fine.
Suggestion: Optional for one euro charge to settle a suitable screwdriver would make the exchange easier to worlds.

Has nothing directly to do with the battery, however: There are four tiny (Torx?) - To loosen the screws, for a well-equipped home improvement will rarely have a screwdriver handy. Ultimately I have drilled away the heads and two screws replaced by Phillips and two omitted. The case was simply glued back. When disassembly is due to the residual screw with a jerk the ribbon cable from the display from the jack slipped and my chunky fingers have broken the lock. Scouted heal with hot glue.
So - no suitable screwdriver is the exchange an odyssey, with it is not trivial but doable.