Tuning Ultegra Di2

[Duci]

Hi folks

I want to use a Ultegra Di2 but not with the original brake-/shift levers. As pritchet74 did i want to integrate it in Campagnolo levers. Has someone already tried to tune a Ultegra Di2? As I heard it is not the same as the Dura Ace Di2?

Many thanks.

Marco

[toiyuet]

By information from internet, to hack Ultegra Di2 is much difficult than Dura Ace.
Hope someone can solve it soon.

[chiva]

I tried to hack my Ultegra Di2 but it didn't work. I tried the aftermarket battery in the seat post wired into the the wire for the battery that goes to the junction box. It seems the new CANbus protocol won't easily allow it. I dremeled the battery mount to try an get the electronics out to put it in line w/ the battery to make it work, but the little electronic boards are glued in and encased pretty securely so it wasn't possible. Maybe Oilman can chime in here and help us out or offer to wire a battery for us for a small fee to get this working. What do you say Oilman?? Pretty please:)

[Jeffr]

Are all of the plugs in the ui2 system two pins only? Are the parts using canbus for power and communication?

[Oilman]

Yes all plugs are for 2 wires, also the wires going from the junction box to the shifters. In each shifter is a micro controller...

The complete system uses one ground wire and one wire for supply + communication.

[Jeffr]

That's interesting. CANbus is a standard but there is no fixed standard for power over CAN. It will take some more effort to extract the signal. Has anyone done this yet?

[chiva]

No, but I wish someone who knows how would. Honestly, I'm clueless. Oilman seems to know what he's doing.

[di2diy]

Hi, I have been selling Di2 modified internal harnesses that put the battery in the seat post on eBay. I also do installs for friends , and few LBS in my area, including drilling non Di2 specific frames (>25). I have had several people ask for the Ui2 battery conversion, I just haven’t got a hold of a battery mount and a cable to check the polarity and verify that the output from the battery is 7.4v. So my question is has/can any one cut a cable that is plugged into a Ui2 battery mount with a fully charged battery check the output and verify the voltage is the same as the Di2 (7.4v) and tell me the color of the two wires and the polarity for each wire. Once I know this I will buy several cables and make up a plug and play kit for anyone to buy and get rid of that ugly battery, and put a battery that will last 100% longer in the seat post.

Link to the Di2 setup I was selling for the Di2… out of cables for now…
http://www.ebay.com/itm/290700600796?ss ... 598wt_1185

Complete harness, soon to be relisted:
http://www.ebay.com/itm/300690872368?ss ... 559wt_1185

[Jeffr]

The ultegra electric has a signal modulated over the dc supply line. Others have reported that you can not simply plug a battery directly into the harness. Someone tried with the calfee system for di2. It may require termination or some kind of passive filters etc. to support this electrically. I doubt it will be as straight forward as di2 has been.

[goodboyr]

If you google "power over 2 wire canbus", you find various writeups on how this is done. Here's an example:

http://people.netfarm.it/~guyver1/ProgettiNetFarm/iButton/AppDesing/onewirebus.pdf

In essence, they use a capacitor and a diode. Whenever the bus is not communicating, the line is charged. During communication, the line drops to lower voltage, and the capacitor discharges. At least I think that's the way it works! I leave it to jeffr to figure out the detail.

ps. I've used di2diy's harness and battery, and it works like a charm. Simple, well made solution!

[Oilman]

The Dallas 1-wire protocol works only for sensors consuming very little power. You would need a huge capacitor to make the front-derailleur shift with such a protocol. My guess is they've modulated the control signals on top of the supply from the battery.

@Jeffr, I thought there would be a passive filter in the battery holder, but after a few simple measurements I think there are also active components. Chiva cracked his battery holder open and he will make some photo's of the electronics inside.

[di2diy]

The ultegra electric has a signal modulated over the dc supply line. Others have reported that you can not simply plug a battery directly into the harness. Someone tried with the calfee system for di2. It may require termination or some kind of passive filters etc. to support this electrically. I doubt it will be as straight forward as di2 has been.

So, if this is true than there must be some circuit in the battery mount itself. That is why I asked if someone has checked the output at the two wires coming out from the mount from a fully charged battery. I would think that the filters/circuit would be in junction box A or B, and the battery cable is just a 7.4v supply source to the circuit.

[goodboyr]

The ultegra electric has a signal modulated over the dc supply line. Others have reported that you can not simply plug a battery directly into the harness. Someone tried with the calfee system for di2. It may require termination or some kind of passive filters etc. to support this electrically. I doubt it will be as straight forward as di2 has been.

So, if this is true than there must be some circuit in the battery mount itself. That is why I asked if someone has checked the output at the two wires coming out from the mount from a fully charged battery. I would think that the filters/circuit would be in junction box A or B, and the battery cable is just a 7.4v supply source to the circuit.

Ok. You might be right. I just checked the voltage at the connector of the battery mount for the ultegra di2 with a charged battery installed. I got 8.04 vdc between the center pin and the shell of the female connector on the battery mount. It was steady (as long as I could keep the voltmeter probes in contact with the tiny pin!). See pictures:

[Jeffr]

You won't be able to detect a rapidly modulated signal with a multimeter. You need an oscilloscope. I will see about getting a set myself to look into it more.

[chiva]

I'm almost done w/ work. As soon as I get home I'll take the pictures of my cracked open battery mount and post them.