Calfee Design offers an elegant solution for the impressive Shimano Dura Ace and Ultegra Di2 electronic shifting systems. This proprietary internal battery and wiring system is available on all Calfee models and also as a retrofit on most frames. Click here for a product summary including technical specifications. Many NAHBS frame builders will be showing bikes with our internal battery and wiring system. In fact, a number have already posted their 2012 show bikes, with our system, on these very pages.
The innovation starts with a custom battery system housed inside the seatpost. We machine an aluminum sleeve that is bonded to the inside of the seatpost and serves to anchor our removable battery. A circlip acts as a stop and retains the battery in the aluminum sleeve. Remove the circlip and the battery is freed. Our battery can be fit in seatposts of any size as we fabricate composite shims to take up any space between the aluminum sleeve that retains the battery and the inner wall of the seatpost. We are also able to fit our battery in aero posts; in some cases, we will use foam instead of our aluminum housing to secure the battery in the post. Importantly, you need only remove your seatpost from your frame to charge your battery. You needn’t remove the battery itself from inside the seatpost; we offer this feature as a thoughtful design detail.
Our Dura Ace Di2 system now includes a charger that eliminates the need to remove the seat post to charge our battery; simply unplug either the front or rear derailleur and plug our charger into the internal wiring harness.
The Calfee solution is 8% lighter and significantly longer lasting than Shimano’s product. In fact, field testing reveals that our battery will last between 2500 and 10,000 miles, depending on temperature and how often the front derailleur is made to move the chain between rings. At a minimum, that is 2 to 3 times longer lasting than the Shimano battery. Conveniently, Shimano’s inline battery life indicator displays our battery’s status. You may charge our battery as often as you like; you needn’t discharge it completely before returning it to the charger that we provide. You will do no damage to our battery either way. Our battery can be completely depleted and recharged hundreds of times before its ability to hold a complete charge begins to slowly diminish. Continue reading here.