Short answer: a Shimano Di2 charger is the dedicated unit that tops up the internal seat-post battery (SM-BTR2 or BT-DN110) used on 11-speed Di2 groupsets. The official Shimano SM-BCR2 is easy to lose and often out of stock, so a UKCA-certified replacement such as the CyclingCharger Di2 internal battery charger (£77.95, free UK delivery) is the quickest way to get shifting again.
If you have landed here, the story is usually one of two: you bought a second-hand Di2 bike and the seller never included the charger, or you mislaid the original a day or two before a big ride. Either way you need the right charger fast — not a cheap adapter of unknown compatibility. This guide explains what a Shimano Di2 charger does, which batteries it fits, and how to buy with confidence in the UK.
What is a Shimano Di2 charger?
Shimano Di2 electronic shifting runs on a rechargeable lithium-ion battery. On 11-speed systems that battery lives inside the seat post, and you charge it through the junction box rather than plugging into the battery directly. The charger delivers a controlled charging profile so the pack is replenished safely, without overheating or overcharging.
The internal batteries used on these systems are the SM-BTR2 and the BT-DN110 (a 7.4V, 3.7Wh lithium-ion pack that also acts as the wireless master unit). The matching Shimano charger is the SM-BCR2, which connects at the bar-end or frame junction box (SM-EW90-A/B or EW-RS910).
Which bikes and batteries does it fit?
A charger for internal Di2 batteries fits 11-speed road groupsets such as Ultegra R8050, Dura-Ace R9150 and GRX RX815, provided they use an internal SM-BTR2 or BT-DN110 battery and a junction box with an accessible charging port. Always confirm your battery model before ordering — it is printed on the unit or listed in your bike's spec.
Note the important exception: 12-speed Di2 (Dura-Ace R9250, Ultegra R8150 and 105 R7150) is a different system. It uses the BT-DN300 battery and charges through a port on the rear derailleur with the EW-EC300 cable — there is no junction box, so an 11-speed junction-box charger will not fit it. If you are unsure which you have, our guide on how to charge Shimano Di2 battery systems walks through identifying your generation.
Why UK riders need a replacement charger
The same pain points come up again and again on club forums and r/bikewrench:
- You bought a used Di2 bike and the dealer forgot to include the charger.
- You mislaid or damaged the original the week of a sportive or cycling holiday.
- Your local shop has none in stock and quotes a premium plus a wait for an order.
- You were caught out with a flat battery and no compatible charger to hand.
When Di2 runs flat the whole drivetrain stops shifting, so a reliable replacement with fast, tracked UK delivery matters far more than shaving a few pounds off an unbranded part.
OEM SM-BCR2 versus a replacement charger
The genuine Shimano SM-BCR2 is the reference charger and also serves as a PC-linkage device for E-TUBE firmware updates. It works well, but it is frequently out of stock and priced at a premium. A well-designed replacement covers the job most riders actually need — routine charging — for less. The things that matter are:
- The correct plug for your junction box (SM-EW90-A/B or EW-RS910).
- A proper lithium-ion charging profile with overcharge and temperature protection.
- UK safety certification — look for UKCA and CE marking.
- A power source you trust; a USB-A cable lets you use any 5V UK plug.
For VAT-registered buyers, the ex-VAT figure is worth noting: the CyclingCharger unit is £77.95 inc VAT, which is £64.96 ex VAT. If you also want to understand how long a charge should last, see our Shimano Di2 battery life guide.
What not to use on a Di2 battery
Never improvise. Do not use power-tool fast chargers, generic bench or cylindrical-cell chargers, adjustable hobby chargers without a Di2 profile, or a random USB cable wired to the terminals. Di2 batteries are sealed units — treat them like a phone battery, not a DIY cell pack. The wrong charger risks permanent damage or a voided warranty.
Travelling to a training camp or race? A compact USB unit is easy to pack — see our portable Di2 charger guide.
The CyclingCharger Di2 charger
The CyclingCharger Di2 internal battery charger is built for exactly this job. It plugs into your SM-EW90-A/B or EW-RS910 junction box and replaces the standard SM-BCR2 charging function for internal SM-BTR2 and BT-DN110 batteries. It charges over a standard USB-A connection (5.0V in, 8.4V DC 1.0A out) in roughly 1.5 to 3 hours, weighs just 45g, and carries UKCA, CE and RoHS marking. It comes with a 12-month warranty, free tracked UK delivery and 30-day returns, is priced at £77.95 inc VAT (£64.96 ex VAT), and is rated 4.8 out of 5 from 256 reviews. It is for 11-speed internal systems only — not 12-speed, external battery mounts or e-bike systems.
Lost your Di2 charger before a big ride?
SM-BTR2 and BT-DN110 compatible · UKCA certified · Free UK delivery · £77.95
Frequently asked questions
How much does a Shimano Di2 charger cost in the UK?
Genuine Shimano charging kits often exceed £100 and are frequently out of stock. A UKCA-certified replacement such as the CyclingCharger unit is £77.95 inc VAT (£64.96 ex VAT) with free tracked UK delivery.
Is a replacement Di2 charger safe for my battery?
Yes, provided it uses the correct lithium-ion charging profile with overcharge and temperature protection and carries UKCA and CE marking. The CyclingCharger unit is purpose-built for internal SM-BTR2 and BT-DN110 batteries and charges through the junction box.
Will this Shimano Di2 charger work with 12-speed Di2?
No. This charger is for 11-speed internal systems (SM-BTR2 and BT-DN110). 12-speed Di2 such as R9250, R8150 and R7150 uses the BT-DN300 battery and charges through the rear derailleur with the EW-EC300 cable.
Can I get a Di2 charger delivered next day in the UK?
The CyclingCharger unit ships with free tracked UK delivery, and buyers regularly report next-day arrival. If you have a sportive or a flight coming up, order early in the day to give the courier the best chance of a quick turnaround.