Looking to upgrade ti ultegra di2 on my giant defy 1. The Defy has a d shaped seat post and seat tube. Does anyone know if the internal battery will fit ok?
It’s a fair wedge of cash to splash to find it won’t fit.

Ta, Naffa

Fits fine – giant do a di2 doofer for the posts but it’s a bit shit so I bound mine in gaffer tape and forced it into the seatpost

https://www.giant-bicycles.com/gb/giant-internal-battery-holder-set-for-di2-black

as aove. no bother.

we build plenty of Defy with Di2, I have a bucket full of the seat post battery adapters.

Thanks for all the answers