Dumb question: Moving a Di2 battery (Giant TCR)?

I’ve got a 2020 Giant TCR and the Di2 battery lives inside the seatpost. Normally this is fine, but is a bit of a pain in the arse when I need to remove the seatpost to get the bike in the back of the car or strip the bike down for flying.

Is it (generally) possible to move the battery to a different position? Ie just leave it in the bottom of the seat tube? (Ive not measured it to check there’s enough room yet!). Presumably I’d need to wrap it in foam or something to stop it rattling around…

Anything I’m not thinking about??

I’ve done this, but tied a draw string around the top so I could get it back out again.  I wrapped in pipe lagging type foam.