Nobody goes Di2 so that they can mount an unsightly battery somewhere on their gorgeous bike. Shimano knows what is up and the internal battery was a quick answer to the complaints of the original external battery. The only needed component is one of the cockpit junction boxes to attach a charger since the battery is no longer easily removable for charging. Either the 3 port SM-EW90-A or the 5 port SM-EW90-F will do the trick.
Internal Battery Shimano Di2 BT-DN110-A-1
Compatibility: Shimano Di2, [charger] SM-BCR2 Includes: 3 washers, c clip, battery mount Claimed Weight: 1.8oz (50g) Manufacturer Warranty: 2 years
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