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What's likely happening is that with time, for one reason or another, the battery isn't locking in securely. When unsupported, it's "falling out" under its own weight. There are couple cheats you can try to employ:
A. You can try gently (gently!) bending out the locking tabs on the battery cartridge.
B. You can secure the battery from underneath using a cinch strap, bungee cord, gaffer's tape... whatever's handy.
If that doesn't cut, then yeah, you'd want to get it in to Elinchrom. At that point it could be as simple as needing a new battery shell (relatively cheap, but expensive if it isn't the problem), or there could be some other internal problem caused by the extra stress when hanging.