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Shimano SM-BTR2 Di2 Battery

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Item # SHI0622

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Item # SHI0622

Hide that battery.

The long-awaited internal battery for Shimano's Di2 electronic groupsets is here. Designed as an alternative to the SM-BTR1-67 Battery, the new cylindrically-shaped SM-BTR2 Di2 Battery was engineered to reside either within the seatpost, seat tube or down tube of your bike. Besides the obviously different shape and mounting location of the new battery, Shimano carried over the proven functionality of the externally mounted battery to this new design. It's still a fully-sealed, 7.4-volt lithium-ion rechargeable unit and provides the same battery life as the external version, but it now comes in at roughly 15g lighter and stays concealed from elements for better protection and improved aesthetics.

Battery life for the SM-BTR2 Di2 is similar to the externally-mounted battery. For the prospective Di2 buyer, know this: running out of juice is nearly impossible. Besides the long battery life and short charges, there is a service light integrated into a module that is part of the shift wire near where it exits the tape under the handlebar. Holding one of the shift paddles down for a few seconds will activate the indicator light. When the light is green, it is fully charged. At 50% charge, it will start flashing green. At 25% charge, it will turn solid red. It will flash red when the battery is critically low.

The Di2 battery lasts from between 600 to 1,500 miles between charges. You can expect that lots of shifting in cold, cold weather will result in shorter battery life, but we've found that 1,000 miles is an average interval. There is no "charge memory" in the battery, so you can recharge it as often as you like, though Shimano recommends once a week or so if you're a daily rider. The battery can go 300 charge cycles at 100% integrity; charging once a week means almost six years.

Please note: Shimano made charging the new internal battery a straightforward affair once you have the compatible parts. You will need one of the new E-Tube Cockpit Junction Boxes (the SM-EW90-A, with three ports, or SM-EW90-F, with five ports) as well as the new SM-BCR2 battery charger. Both of these junction boxes were built with an external charging port for the new charger. This is the only way to charge the new battery. Similar to the external battery, the new SM-BTR2 Di2 battery takes 1.5 hours for the battery to receive a complete charge. It uses lithium-ion technology to maximize output and minimize size.

The Shimano SM-BTR2 Di2 Battery is currently shipping with a seatpost assembly mounting hardware package, but frame-specific hardware is also available from select manufacturers. Pinarello's new Seatpost Internal Battery Mount for Di2 is compatible with its Dogma 60.1, Dogma 2, and Dogma 65.1 seatposts.

  • Resides within seatpost, seat tube, or down tube
  • Fully-sealed 7.4-volt lithium-ion rechargeable battery
  • Comes with seatpost assembly mounting hardware
  • E-Tube Cockpit Junction Box, SM-BCR2 battery charger not included
  • 600 to 1,500-mile range
  • 1.5-hour recharge time

Tech Specs

Shimano Di2
Recommended Use:
powering up
Manufacturer Warranty:
2 years
Actual Weight:
One Color, One Size: 58g

Size chart


Di2 Reference Guide


Note: This reference is meant to be used as a guide for creating a Shimano Di2 drivetrain package. For further assistance please feel free to give us a call.


Battery and Wires:

Our Shimano Di2 packages are built for three standard configurations based on battery location and wire routing. First, you'll need to determine if your frame uses an internal or external battery mount, and whether the routing is either internal or external. Below is a guide for which battery, charger, mount, and junction boxes are required for your configuration.

Battery and Wire Configurations
 BatteryBattery ChargerBattery MountJunction AJunction B

External Battery

w/ External Routing

SM-BTR1 SM-BCR1 SM-BMR2 SM-EW90 A/B 3/5 port SM-JC40

External Battery

w/ Internal Routing

SM-BTR1 SM-BCR1 SM-BMR2 SM-EW90 A/B 3/5 port SM-JC41

Internal Battery

w/ Internal Routing

SM-BTR2 SM-BCR2   SM-EW90 A/B 3/5 port SM-JC41

Battery Mounts:

The SM-BMR2 battery mount is available in three configurations -- Long External, Short External, and Long Internal. Both Long versions are to be mounted using the bottle cage mounts, while the Short version is designed for Di2-specific frames with either a chainstay or down tube mounting location.



There are two junctions needed for completing your Di2 build -- A and B.  Junction A, SM-EW90, is located at the handlebars and available in both three- and five-port options. The three-port option is intended for standard shifting with a left and right hand shifter. If you have the intention of using Shimano's satellite sprint shifters, or a combination of time trial shifters and shifter/brake levers, the five-port junction box will be the necessary selection.

Depending on your frame specification, Junction B (SM-JC40 or SM-JC41) is located either internally or externally at the bottom bracket area. Accordingly, SM-JC41 is designed for frames with internal wire routing, while SM-JC40 is intended for external wiring options.


E-Tube Wires:

For your convenience, we've created wire packages for your Di2 build kit in the sizes Small, Medium, and Large. Below, you'll find which wire lengths are included in each kit. Additionally, we've recommended a kit size based on your frame size.

 E-Tube Wire Length Chart
Down Tube Wire 700mm 750mm 950mm
Front Derailleur Wire 300mm 350mm 400mm
Rear Derailleur Wire 500mm 550mm 600mm
Battery Wire 300mm 350mm 400mm


 E-Tube Wire Frame Size Guide
Frame Size  47-52cm 53-56cm   57+cm

Please Note:

E-Tube Wire length suggestions are an approximation. 

Reviews & Community


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Avg. ride time: 22h 36m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Great Design...with one minor draw back

  • Familiarity: I've put it through the wringer

The internal battery is in many ways superior to the external battery. I have both types on different bikes. While I have never had problems with the external battery getting damaged, the internal battery requires riders to be more vigilant about keeping it charged. That is, I own two external batteries and if for some reason one is low (or in one case dead) before a ride I can simply swap out batteries. This is not as easily done with the internal battery. One can even ride with an additional external battery in your pocket for added safety. So what do you do? Well if you get a Di2 D-Fly and a Garmin you can have the Garmin display the Di2 battery level on your screen as a percentage. This is what I have done for my internal battery mount.

On a more general note, I wish Shimano would stop listing the life of a full charge in distance. It is a pretty pointless metric. When I ride on flats I can go for thousands of miles without a recharge. On hills where I shift much, much more frequently (especially on the energy intensive front rings) I get about 400 miles. Also the batteries degrade with time like any rechargeable battery and so it gets harder and harder to judge the time/miles/shifts you have left before it goes dead. The little indicator lights in the front are very very rough measures. Frankly, Shimano needs to have the junction box display a percentage. Until then I would suggest getting a D-Fly.

It is possible to check the battery level by pressing and holding any shift button for 1.5 seconds (I always do so with the front derailleur, and do a redundant shift onto the same chain ring I am already on). When you do so, the junction box will provide one of 4 lights.

- Solid green = >50%
- Blinking green = 25-50%
- Solid Red = 10-25%
- Blinking Red = <10%

Not quite as easy as having a display with actual battery level, but at least indicates when charging is needed.

Bradley Gehrig
Customer Account Manager
Office: 801–204-4541

Avg. ride time: 11h 2m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Internal Looks Oh so Good!

    Make your road setup sleek as it gets with an internal Di2 setup.

    Electronic's a thing of beauty! If you have any questions on what you need, please give our customer service "Gearhead" team a call!


    Avg. ride time: 5m per week
    • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

    Love the internal mount!

    • Familiarity: I've put it through the wringer

    Gone are the days of the gaudy external battery! The stealthy seatpost hidden battery lasts just as long and is a "set it and forget it" item which we all love!

    Unanswered Question

    If I already have a junction box, wires, etc, but am looking to switch from external to internal battery, all I need is this battery and the internal battery charger correct? Assuming my wires are long enough.



    Hi James,

    It depends on what you already have.

    You will need; Shimano SM-BTR2 Di2 Battery, Item # SHI0622.

    Shimano Di2 Internal Battery Charger, Item # SHI0647

    Shimano E-Tube Cockpit Junction Box - SM-EW90 A/B 3 port, Item # SHI0650

    Shimano E-Tube Di2 Wire, Item # SHI0398 long 750-1000 depending on your frame size.

    And some bikes can use Pinarello Seatpost Internal Battery Mount for Di2, Item # PIN0138.

    If you have any questions please give us a call; 888-736-6396