I'm looking to run a 1x10 Di2 setup on my TT bike. I've purchased the Shimano rear der and front wiring harness (it's in the mail), but would like to use custom bits for everything else.

Instead of putting the battery inside the seatpost, I've decided I'm going to try to put it inside one of the aero bar extensions. This would allow me to run one cable from the handlebar area all the way to the rear der. The extension has a 19mm id. Does anyone have any suggestions on a battery that would fit inside there?

Also, would any of the plugs on the front wiring harness fit into the rear der? I'm going to solder all my connection to this harness anyway. And if I can use one of those plugs to run into the rear der, that would save me some money. I would solder the plug onto the end of my one, long cable.

Thanks,
Scott

The brain of the di2 setup is in the front derailleur i'm sure. I'm not sure your plan is going to work I'm afraid.

EDIT: Having had a quick look around, it seems it's possible to do a 1x10 setup after all. Just requires a bit of hacking it seems.

Hi

I have done pretty much what you are thinking about on my latest tt build. (well almost, i put the battery in the stem)

I use a Hyperion G3 CX Lipo battery. I have different version, but sizes up to 550mah should fit inside 19mm.

The front derailleur uses much more power than the rear, so going 1x10, you can go with a much smaller battery. I have used 240mah and 350mah.

check my build:

viewtopic.php?f=10&t=86083" onclick="window.open(this.href);return false;

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www.sykkelplaneten.no

Awesome Trek.

Thanks for the recommendation on the battery. What charger are you using?

Thanks,
Scott