# I paid $100 for this Di2 charger and it doesn't have an AC adapter?!?



## miataeric (Jun 4, 2013)

I have just had to plug my bike in for the first time to charge the battery. For some random reason, I decided to check the status after my ride this morning and it had gone to solid red, so I broke out the charger. Aside from the weird feeling of having to plug my bike in, I am disappointed that Shimano doesn't include an AC adapter to plug it into the wall.

I breezed through the instructions (NO, I'm not turning in my man card!), and it turns out that both of the AC adapters that I have and use for all my other electronics don't meet the output requirements that Shimano says to use to avoid overheating the charger and starting a fire.

I started off plugging it into an Amazon adapter that I had, before reading those pesky instructions. Now the only thing that I have that meets Shimano's output requirements is a portable battery recharger. So now I have a battery charging a battery..... This is going to take some getting used to!


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## 06SpiceRed (Aug 3, 2012)

I agree its absurd that when you buy the charger it doesnt come with the wall plug. When I purchased my Di2 groups for my bikes I made sure that ALL of them came with a charger and a plug. Sure I only charge my battery MAYBE once a year (since I have a few bikes with Di2) and it isnt too big of a deal but if im paying some good coin for this, im getting everything I want with it.


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## scottma (May 18, 2012)

The only thing that I was not happy with on the 6870 upgrade was the charger. It starts as USB to micro USB. So far, so good. Then it goes to a brick...not so good. Then to a tiny proprietary connector to the A junction. Blah. Why not keep it micro USB? I had a USB AC adapter kicking around so that was not a big deal. Really nit picking though. The charging activity is not something to deal with very often. Super system!


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## Neb (Sep 8, 2012)

scottma said:


> Then it goes to a brick...not so good. Then to a tiny proprietary connector to the A junction. Blah. Why not keep it micro USB?


Just FYI, but the reason why is due to the voltage differences; standard USB runs at 5V while the Di2 system charges at 8.4v. Using a micro USB connector means that someone, somewhere, will eventually plug something else other than the charger to the junction box and blow something up.


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## scottma (May 18, 2012)

Thnx Neb. That is a good explanation.


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## scottma (May 18, 2012)

A bit more info on the AC charger requirements. The requirement is for a charger with 1A or greater. The one I was using had an unreadable label, but it seemed to work fine. I went to charge the system up yesterday and saw the light on the charger brick was blinking. The manual said this could be due to using a charger of < 1A. I found another charger kicking around that was labeled 5V 1A and it fixed it. Just some info in case anyone else runs into this.


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## bikingmeditation (Apr 23, 2013)

Not including the AC adapter is irresponsible. If it had the same voltage requirements as 90% of the gadgets, then ok to no wall adapter. It's not. They should have included one.

Lucky that I've been getting about 2500 miles per charge. This is estimated since I only go down to 50% before charging and I had somewhere put in about 1100-1300 miles (the range is because I had indoor hours and no way to determine mileage).


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## scottma (May 18, 2012)

The voltage requirements are standard USB adapter 5V. I have a drawer full of adapters like that from old cell phones and such. The only thing is to be sure it is rated for 1A or greater. Some of mine are, some were not.


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## rubber_duckie (Apr 24, 2012)

I'm using Apple Iphone USB adapter and checked the Shimano Di2 battery spec and compared and it the same.


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## Cut.Aussie (Mar 19, 2011)

Not including a power pack seems like a good idea to me, have you any idea how many different voltages and mains plug types there are in the world? That means Shimano would need to sell lots of different versions driving cost up even higher.

And really, just about everyone has a device with a USB port, pc, laptop, smartphone, iPad etc. anyone of these will happy charge your Di2, even airport/railway lounges have usb charging stations these days.


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## egebhardt (Feb 17, 2007)

To the OP...
your charger is also a USB to Computer programming/firmware updating machine. That's what your 100 bux went to.

Also, the battery you are charging is a 2cell 7.4v 500mAh Lipo.
Dozens of $10 chargers can do that job. I'll never buy a Shimano charger for any of their batteries. All you need is a charger that pushes 1 amp and stops once it hits 8.4v. The internal batteries are a pain in the butt if you ask me. I buy 1000mAh batteries on Ebay for $10 each. They last twice as long. I tape it to the frame anywhere. I can have 12 backups for the price of one SM-BTR2 at the same weight.


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