I use the long bracket that goes underneath the water bottle cage. Fits just fine on the downtube. The water bottle mount goes under the cage. You use the cage bolts to hold the mount on the bike. The cage works just fine to hold a bottle a little higher on the downtube than the battery. Look at your current bike with a water bottle cage on the downtube. One inch below the cage is where the battery will sit. The battery is about 3 inches long. The battery fits in the space between the bottom of the cage, and the junction where the down and seat tubes meet.



On Friday, November 10, 2017 at 2:48:52 PM UTC-6, yirgster wrote:
I'm upgrading my 2010 bike to ultegra di2 with the external kit.

So, my question is whether to go for the long external battery mount (S-BMR1-LB) for the water bottle cage, or the short mount (SM-BMR1-S) which mounts on the chainstay or downtube.

If going with the water bottle mount does it prevent using the cage for a water bottle?

Any thoughts most appreciated. TIA!