I'm considering switching from Campy Super Record to EPS with the V2 power unit, but I'm unsure about mounting locations for the new power unit on my Cervelo S2. Anyone have any experience or advice for mounting location or method for the new power unit on an S2 (2011 S2)? I'll likely be upgrading to a new frame that will be more accepting of an internal battery mount.

I have no experience with the S2, but I have two bikes with internal Super Record/Record EPS. Two things to keep in mind, first, the smallest internal diameter of the seat post is usually right behind the bottle cage bosses, make sure you clear those as that is the mounting point. Second, you need to have a way to exit the frame for the charging port. I used the drain hole under the BB for my wife's Parlee Z5SLi and I used the secondary entry hole for the Di2 external battery on my NeilPryde Bura SL.

_________________
"Suddenly the thought struck me; my floor is someone elses ceiling" - Nils Ferlin

Thanks for the input, but unfortunately the S2 won't allow for internal mounting of the battery. I can run the cabling internally, but I will have to mount the battery somewhere externally. I'm thinking about using double sided tape and zip ties on the chainstay as a temporary solution until I choose a more EPS friendly frame. It won't be elegant, but it will get the job done.

In the seat post it's self??

_________________
project black

Under the saddle. Should fit between the rails. Can't remember the length and since mine is installed inside the frame, it's too much hassle to check.

That's an interesting idea. I'll have to check the length of the battery to see if that type of setup would work.

.

According to Cervelo, the battery won't fit in the seat tube. I agree that it looks like it is big enough. I haven't personally measured and I can't find dimensions online, but I'd really prefer if it would fit.

Anyone have insight into the precise dimensions on the S2 seat tube?

.

Through the head tube is the go and mount in the down tube, just depends on your frame size.
I have done it before on bikes but you will need a special threaded cable install tool or make one.