# Di2 Custom Build - no wires



## diablo2112 (Nov 7, 2007)

Here's a few pics of my just-finished build. 2011 Specialized SL3 Roubaix. Full Shimano Di2, Shimano Pro bar.

I have a thing for wires and zip ties, so spent a bit of time hiding everything on this build. Cut the Di2 harness and routed through the frame. A few other goodies included disassembling the Di2 battery and re-working it into the seat post (retains stock battery connector for charging). I added an auxillary shift switch, which I also disassembled to custom mount onto the bars with no wires.

Finally, I shipped in the new SC7900 flightdeck computer (from Japan), which integrates many Di2 functions. This eliminates the unsightly front-wire harness, which zip-tied to the brake cables. I have a bit of experience setting up the new SC7900 computer, and it wasn't easy. I can understand why Shimano has not yet released this in the US. I'm still waiting on the Shimano Pro computer mount (which integrates with the Pro Evo bars); the mount in the pics below is temporary.

I ride in the mountains of northern New Mexico. Went with a 34/50 compact and 11-28 cassette. Cassette works just fine with the Di2 system (as others have found).

Final weight, all-up is 16# 11oz. Snow on the ground, so no ride-time yet. 

Enjoy.


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## Dajianshan (Jul 15, 2007)

Nice battery trick!


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## robdamanii (Feb 13, 2006)

Hole...

E....

Crap...


That is absolutely fricken' AWESOME!

Love the integration of the battery in the seat post, and the integration using the flight deck. If I can ask, how is the flight deck computer (I understand it has GPS function as well?)

Are you per chance an EE or Electrician or something of that nature?


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## Richard (Feb 17, 2006)

Very cool.......but I think you just voided your frame warranty.


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## diablo2112 (Nov 7, 2007)

Thanks. Frame warranty is still good; warranty on the wiring harnesses is toast. No mods to the frame at all, and the SL3 is supplied with Di2 instructions. And yes, I'm an engineer (chemical, but that's a minor detail).

As far as I know, the SC7900 does not have GPS capability. It does do altitude and slope, but I think it's barometric pressure based. Integration of the SC7900 with Di2 is very good, otherwise, the SC7900 is pricey and other bike computers do a better job of pure biking functions. I do like the integration, including gear indicators, indication of the offset when trimming the Di2, and buttons in the shifter hoods are used to change computer functions.

The PITA aspect of the SC7900 was pairing the computer with all the wireless connections. Shimano supplies an accessory sheet with the strangest instructions, including instructions to short (short!) the battery contacts in the speed and heart-rate sensors if they don't pair "after several attempts" in order to "eliminate any residual charge". I'm certain this is the reason the SC7900 has been delayed in shipping; not nearly ready for the masses.


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## cxwrench (Nov 9, 2004)

holeeeeee hell that bike looks great! very nice job on every aspect of the build...enjoy it when the snow melts!


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## aengbretson (Sep 17, 2009)

From one engineer (mechanical) to another, BRAVO! That is top-notch. That is a new level of cleanness, you are my hero.


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## robdamanii (Feb 13, 2006)

My god, I'm still in AWE of that. I just love the integration.

Heh, you could probably make a pretty solid buck by performing that service for folks if you ever wanted a side job.


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## frdfandc (Nov 27, 2007)

As a mechanic at a LBS, WOW, that is the cleanest setup I have ever seen. AWESOME.


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## diablo2112 (Nov 7, 2007)

Thanks for all the nice compliments, I do really appreciate them, and appreciate that folks here understand the effort it takes to get a clean build. 

I had a request for a pic of the cable entrances at the head tube. Here you go, and thanks again.


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## ZoSoSwiM (Mar 7, 2008)

OMG you built up one hell of a clean looking bike. Love what you did with the battery. 
Just a thought.. but if anyone knows of a seat post with an open top you might be able to avoid pulling the post to charge the battery. Damn cool as is though!!


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## ewitz (Sep 11, 2002)

Nice job but marble tape?


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## diablo2112 (Nov 7, 2007)

Yes, I need to change the bar tape. It's what I had in my shop; I've got some straight-white and orange on order (My LBS is 60 minutes away; I did get the frame and other parts from them - support your LBS!).

After some thought, I prefer not having an opening in the seat post. This weather-seals the battery, a good thing. Battery charge on the Di2 lasts forever, and pulling the seatpost to recharge is both infrequent and very easy.


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## jcuesico (Mar 25, 2004)

WOW, what a nice clean build. Thanks for sharing.


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## cpcritter (Sep 24, 2008)

I bought a used SL3 w/Di2 and was somewhat disappointed with the standard protocal build using tape, exposed wires and clunky battery mount. I will rework this bike in a similar manner to your build. You did a very nice job.

Did you drill the holes in your frame? Did you cut and reconnect your wires? Are you worried about voiding warranties.


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## diablo2112 (Nov 7, 2007)

Not cutting or drilling of the frame at all. I did drill 2 holes in the Pro Evo bar (small, self-tapping screws, thin CA glue prior to seal fiber) to mount the aux shifter.

Best to cut the wire harness for your routing. No question, I voided the warranty on the wiring harness, battery, and (probably) the aux shift switch. Not worried at all about warranty on the frame, and haven't modded or drilled the pricey bits of the Di2, so no worries there, either.

Note that going to the internal version of the Di2 would have been an option, but even then, I wouldn't have gotten the very clean frame grommets. Shimano supplies rubber boots for the entrances, which look great, but not quite as clean as this build. I'm extremely comfortable cutting, splicing, and disassembling/reassembling stuff, so this wasn't a big deal. If you're less comfortable with such things, best to leave the delicate splicing work to others. A good soldering iron is a must (I like Weller temperature controlled pencils).


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## olr1 (Apr 2, 2005)

The left hand bar end plug is not vertically aligned, which has spoiled the whole thing for me.

Close, but no cigar.


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## diablo2112 (Nov 7, 2007)

olr1 said:


> The left hand bar end plug is not vertically aligned, which has spoiled the whole thing for me.
> 
> Close, but no cigar.


You missed the mis-matched valve stem lengths.


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## ukbloke (Sep 1, 2007)

Can you download data from the new Flight Deck SC7900 to a PC? Thanks.


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## diablo2112 (Nov 7, 2007)

Yes, the SC7900 supports download to a PC. It's wireless, though you have to purchase a USB dongle and software separately (about $50). The SC7900 can be setup to take ride data at different intervals, default is every 4 seconds which gives about 40 hours of recording time. There's a "file" menu on the SC7900 which allows playback, transfer, delete, etc.


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## GirchyGirchy (Feb 12, 2004)

Screw the bike, I want more pictures of your house.

That's pretty cool. Very nice work.


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## jd3 (Oct 8, 2004)

Beautiful build. I have the same frame on the way. One point though, it's probably not a good idea to post pics of your serial number on the internet.


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## diablo2112 (Nov 7, 2007)

Finally got some decent bar tape and a good set of wheels/tires. Fulcrum Racing Zero with Hutchinson Tubeless. Quite fortunately, the rims are anodized nearly a spot-on red/orange which perfectly matches the frame.


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## bismo37 (Mar 22, 2002)

gah! :yesnod: That's a super nice, super clean build.


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## Special Eyes (Feb 2, 2011)

What's with the wiring of the seat?


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## simonaway427 (Jul 12, 2010)

sooooo clean.

Very, very nice work.


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## bywayof (Apr 8, 2010)

Fantastic! Thanks for your post. I'll bet it was a lot of fun building that up.


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## bikedad4life (Apr 9, 2009)

look awesome ! question did you modify the original battery or did you use new battery cells?


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## diablo2112 (Nov 7, 2007)

Modified the Shimano battery. Just to document what I did, here's some details.

Cut open the battery with a dremel cutting wheel, cut the edge of the battery case at each corner just enough to cut through the shanks of the 3 screws.

A few things to be aware of. There's a circuit board in the battery. It contains charge monitoring circuits. I unsoldered this from the actual battery, which has three connections. These connections are positive and negative terminals and a temperature monitor (at least, I think that's what this is, it may be an intermediate voltage monitor, too). This last connection is important, as the battery monitors it during charging (whether temperature or voltage), and uses that to help determine when the charge is done.

I carefully unsoldered each of the connections, being careful not to pry the board up to far from the charge plug in the battery (you'll see this when you open it up). I then cut away the internal casing that held the battery together, and (carefully) spread the battery into a single, in-line unit. Try to keep as much of the silicon insulation in place between the batteries (at the opposite end of the circuit board) when you do this, the temperature sensor has been buried inside this, if that's what it is. 

With the batteries in-line, I soldered three extension lines, and wrapped the battery in electrical tape to my satisfaction that nothing would short. I put the battery in the seat tube, extended the 3 wires to the circuit board, and soldered them at a right-angle back on the board. This allowed the board/plug to fit in the seat tube. Some careful electrical tape was used to insulate this. See my pic of what the plug looks like on both ends.


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## jczajka (May 29, 2006)

*FlightDeck*

Where did you order the flightdeck computer and wiring from?

I have a Similar Roubaix and have been trying to find the computer and wire harness.


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## diablo2112 (Nov 7, 2007)

Alex's Cycles in Japan. Imported it. A bit pricey.

Looks 100% better with good bar tape, and a proper computer mount (from Pro/Shimano).


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## jczajka (May 29, 2006)

Looks so much cleaner. It is too much money though. Thats why Shimano never released it in the US, nobody wanted to pay $500 for a computer that doesnt do GPS, ant+, etc.


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## ski4by (Sep 3, 2011)

very sweet


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## raf88 (Nov 9, 2011)

*Di2 battery polarity*

Hello,
First time on this forum, I am really interested by customized Di2 battery that some of you did
I have a project to do Di2 battery integration on my 695 frame. I want to replace the original Di2 battery (that I will not buy) by RC battery.
My concern is the battery polarity, I can’t measure polarity and define how to connect RC battery.
Can someone of you help me and give me advice on how I can recognize where I put the + and – of the battery on the Di2 harness (wire color, something else)?

Thank you


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## raf88 (Nov 9, 2011)

Hello,
First time on this forum, I am really interested by customized Di2 battery that some of you did
I have a project to do Di2 battery integration on my 695 frame. I want to replace the original Di2 battery (that I will not buy) by RC battery.
My concern is the battery polarity, I can’t measure polarity and define how to connect RC battery.
Can someone of you help me and give me advice on how I can recognize where I put the + and – of the battery on the Di2 harness (wire color, something else)?

Thank you


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## robdamanii (Feb 13, 2006)

Use a multimeter?


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## raf88 (Nov 9, 2011)

I was probably not clear: I don't have the shimano battery and don't want to buy it (more than 120$/€) and immediatly replace it by a custom battery.
this is the reason I am asking.


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## robdamanii (Feb 13, 2006)

raf88 said:


> I was probably not clear: I don't have the shimano battery and don't want to buy it (more than 120$/€) and immediatly replace it by a custom battery.
> this is the reason I am asking.


Maybe just ask a shop if you can multimeter it?


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## raf88 (Nov 9, 2011)

the objective was not to buy in a shop so difficult to go in a shop and ask this...
thant's why i am asking for experience of people who already did the job


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## alias33 (Sep 15, 2008)

drilling the carbon bars to mount an aux shifter is a bit excessive (and a safety issue) 

also, cut the extra 3 inches off your rear brake cable, geez!


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## eschummer (Jul 29, 2011)

What a great job, diablo! You are an inspiration to many of us! I have the same bike, but my Di2 components (upgrade kit) have not come in yet, but I'm told they're on their way. 

Was most of the soldering getting the right cable lengths? I imagine the battery extension being one (lengthen), and the individual actuator cables from the junction box (shorten). I'm not sure about your aux switch on the bar. Do you find that you use it a lot? Seems once you have electronic control you could put additional switches anywhere (just parallel splice into the existing wires), but not ever having had one I wonder about its use...

Great build!

Ed


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## nayr497 (Nov 8, 2008)

ewitz said:


> Nice job but marble tape?


That's what I was thinking, except the word that came to mind was "splash" not marble.

Very cool custom job. And I'm glad you changed the tape:thumbsup:


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## BCP (Nov 3, 2011)

Wow, clean build! Nice work and a very impressive bike.


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## GirchyGirchy (Feb 12, 2004)

alias33 said:


> also, cut the extra 3 inches off your rear brake cable, geez!


Why, so he can't turn the bars to the right?


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## viciouscycle (Aug 22, 2009)

Just an idle thought, what if any issues might there be with the battery due to heat due to no air movement during use and recharging?


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## eschummer (Jul 29, 2011)

eschummer said:


> Was most of the soldering getting the right cable lengths? I imagine the battery extension being one (lengthen), and the individual actuator cables from the junction box (shorten).
> Ed


Should have read your intermediate post - duh! Sorry!

Thanks for the great description! Sounds like doable but definitely not for the faint-hearted. What technology are the Shimano batteries? NimH or LiPo?

Thanks!

Ed


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## MisterMike (Aug 12, 2004)

diablo2112 said:


> ...And yes, I'm an engineer (chemical, but that's a minor detail).


 I'm an EE and most of the ChemEs I knew were far from being "minor" in there differences from other engineers. but, they were all pretty brilliant I must add.

Anyway..pulling your chain. That's a beautiful job you did on a beautiful bike. It's clear ChemEs suffer from the same compulsion for detail that most other engineers suffer from. Enjoy it.


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## Cerveloboy (Mar 8, 2007)

Hi there,

First of all thanks for taking the time to write about your di2 build. You inspired me to take the time to search for a flightdeck computer to include as part of my own di2 build.

I've only just completed it, but I need some help on the computer itself. As you know, most bike shops don't even know that the SC7900 exists let alone know how to set it up.

Anyhow... here are my questions.

I have managed to pair with the speed sensor, but I can't seem to get the shifter buttons to function, nor can I get a readout for cadence (it remains at zero even though the speed is registering), I don't see any active gear selection, and I don't see a readout for the di2 battery life.

Do I have to pair the actual bracket? Any help would be greatly appreciated.

Thanks,
Shaun


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## PaxRomana (Jan 16, 2012)

This is freaking spectacular. Major respect for the workmanship.


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## diablo2112 (Nov 7, 2007)

Cerveloboy said:


> Hi there,
> 
> First of all thanks for taking the time to write about your di2 build. You inspired me to take the time to search for a flightdeck computer to include as part of my own di2 build.
> 
> ...


It's been a year since I set this up, but as I recall, pairing the various components was a major pain. In fact, I think this is probably the reason that Shimano has never released the SC7900 in the US. There was an insert with the computer with some VERY strange instructions for pairing. They said to take the battery out of each component, insert them, and try to pair them. If that doesn't work, you were to short the battery terminals in the SC7900 itself by touching a paper clip to both the positive and negative tabs (with NO battery inserted) and then attempt to repair each component. I had to do this (touching the battery terminals with a conducter and then inserting the battery) for both the speed and cadence sensors to get the unit to recognize them. Once they were paired, I haven't had problems since. Check the inserts that came with the computer carefully, and follow those instructions.

Hope this helps.

Joe M.

P.S. This fall, I did a similar build on a bike for my fiance. Wooden Renovo R4. Here's a few pics; I really should get a better set up and do build report.


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## Cerveloboy (Mar 8, 2007)

Thanks Joe,

I will search for the insert and if necessary try the paper clip suggestion. One last question, does the Computer need to be paired with the bracket itself? I assume so, as the pairing section shows "SPD" for speed sensor, and "BKT" for bracket?. I've searched the instructions and it seems that pairing with the speed sensor and hr strap are accomplished by inserting the batteries during the pairing process. However since the bracket itself doesn't have a battery I'm a little lost on how to pair it. I will investigate tonight when I get home.

Thanks again.
Shaun


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## diablo2112 (Nov 7, 2007)

As I recall, the bracket does have to paired as well, and it does have a battery, it's powered by the main DI2 battery pack. I had to unplug/replug the DI2 battery to get the bracket to pair as well, along with the paper-clip trick. As I said, it was a complete pain to get the various items paired with the SC7900; I'm certain this is why Shimano never put the SC7900 into wide release outside Japan.

This is from the front page of the manual:

Notes when making pairing settings
For details on pairing, refer to page 11 of the Service Instructions. • 
When pairing the speed sensor and the heart rate sensor
unit, push the battery to the bottom with your finger and hold it there. * 

If pairing did not occur, remove the battery, wait for
about 10 seconds, and then reinsert the battery and
repeat the pairing operation. 

After pairing is complete, close the battery cap.

Pairing settings which have already been completed will not be erased even if the battery is removed.

---------
I tried this many times, and it still didn't work for the bracket or speed sensor. Finally, after removing the battery, I shorted the 2 terminals with a paper clip, reinserted the battery, and it finally paired. Hope this helps.

edit: more good info on pairing the SC7900 is found here: Topic : "Shimano DuraAce Di2 ST-7970" and the - FixYa


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## Cerveloboy (Mar 8, 2007)

Thanks Joe. I checked out that link, all that was missing was the rain dance! I think my problem is that I wasn't disconnecting the di2 battery (mine is a calfee seatpost mount) during the pairing sequence. Stay tuned for my follow up report.

Shaun


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## Cerveloboy (Mar 8, 2007)

Well I'm happy to report that I was able to pair the SC7900 successfully with the di2 battery and it's working as designed. Thanks for your help Joe.

Shaun


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## 55x11 (Apr 24, 2006)

Gorgeous bike and very clean install. I am jealous!


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## ddimick (Aug 9, 2011)

That Renovo is really beautiful. I'd be terrified to take it outside!


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## projectfreedom (Mar 10, 2012)

this is a work of art, my friend! great job on the build and doubly so on documenting it. good photo skills


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## diablo2112 (Nov 7, 2007)

projectfreedom said:


> this is a work of art, my friend! great job on the build and doubly so on documenting it. good photo skills


Thanks so much. I've recently completed a second build for my fiancé, Renovo Wooden Frame and DI2. Here's a few quickie pics, I really need to get a better set of photos. I really need to setup another thread to show this gorgeous bike. Also put the battery in the seatpost, etc.


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## DiabloScott (May 13, 2003)

Well from one Diablo Engineer to another... that was just awesome... didn't see this post until today. 

I like my 10speed regular Flight Deck but I suppose I can give up the gear indicator for GPS and power on my next machine... which WILL have Di2.


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## DiabloScott (May 13, 2003)

Well from one Diablo Engineer to another... that was just awesome... didn't see this post until today. 

I like my 10speed regular Flight Deck but I suppose I can give up the gear indicator for GPS and power on my next machine... which WILL have Di2.

diabloscott.blogspot.com


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## de Ron (Jan 13, 2008)

*Internal battery*

Hello,

Very nice job ! Beautiful, awesome !

Just a question as you inspired me to implement a similar clean solution: 
is the calfee DI2 seatpost internal battery solution an alternative solution, whereby you don't need to take apart the Shimano DI2 battery ?


Ron


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## diablo2112 (Nov 7, 2007)

Ron,

Yes, the Calfee is another good battery solution. I'm told there's several companies now offering seat-post batteries for the DI2. I'd gently suggest that taking apart the Shimano stock battery is a more advanced project for the DIYer. I had to use a dremel tool, and was careful about how I got it apart. If you're not comfortable with wiring, soldering, and working around batteries, then I'd recommend the Calfee or other supplier.


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## vince1989 (Nov 6, 2012)

what did you do with the electronic how is in the battery?


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## diablo2112 (Nov 7, 2007)

vince1989 said:


> what did you do with the electronic how is in the battery?


I cut the battery open, and extended the thermocouple wire, the positive, and the ground to the electrical socket and electronics board which I retained, along with the stock plug (to enable use of the stock DI2 charger). Hard to describe in words. I'll try to get a picture of the whole assembly up, easy to see in pics.


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## vince1989 (Nov 6, 2012)

yes in words it's hard to describe thx for the picture


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## Mud (Feb 5, 2002)

I have a feeling the next "big" thing in electronic shifting is going to be wireless. With wireless technology everywhere now, it's just a matter of time before we see it showing up on bikes. The key, of course, will be to get power to the derailleurs - small watch-type battery maybe??

But, your bike looks wireless to me. Amazing work there!


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## Zen Cyclery (Mar 10, 2009)

diablo2112 said:


> Thanks so much. I've recently completed a second build for my fiancé, Renovo Wooden Frame and DI2. Here's a few quickie pics, I really need to get a better set of photos. I really need to setup another thread to show this gorgeous bike. Also put the battery in the seatpost, etc.


How is the ride quality of this frame? I have been contemplating whether or not that would be a good direction to go for my next road bike. Does it feel overly damp?


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## Duane Gran (Feb 3, 2004)

Mud said:


> I have a feeling the next "big" thing in electronic shifting is going to be wireless. With wireless technology everywhere now, it's just a matter of time before we see it showing up on bikes. The key, of course, will be to get power to the derailleurs - small watch-type battery maybe??


Going wireless creates more battery requirements. If no wire runs from the shifters then they need a power source in addition to the derailleurs. The wire is an elegant solution to route power and signal between four points on the bike. It also is resistant to interference, so I suspect wires are here to stay but internal routing eliminates most of the problem while retaining the simplicity of one battery in the current design.

The next break through could be lighter batteries though. Shimano over engineered the battery life on these thing in my opinion because everyone's first objection is that they don't want to get stranded on a ride. The supplied battery can run for 3 months for most people between charges. There are also some emerging technologies to rapidly charge batteries which would enable smaller batteries because the refill time would be trivial.


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## Full_Spectrum (Oct 30, 2012)

Duane Gran said:


> Going wireless creates more battery requirements. If no wire runs from the shifters then they need a power source in addition to the derailleurs. The wire is an elegant solution to route power and signal between four points on the bike. It also is resistant to interference, so I suspect wires are here to stay but internal routing eliminates most of the problem while retaining the simplicity of one battery in the current design.
> 
> The next break through could be lighter batteries though. Shimano over engineered the battery life on these thing in my opinion because everyone's first objection is that they don't want to get stranded on a ride. The supplied battery can run for 3 months for most people between charges. There are also some emerging technologies to rapidly charge batteries which would enable smaller batteries because the refill time would be trivial.


Mostly true. I am surprised that no one has mentioned the size of the wires. No need to have such large wires in this system, since the current and voltage are so low. There are many grams to be trimmed here by finding some decent wire.

For battery tech, Shimano has actually done a pretty decent job here, considering they offer a warranty, and are meant for the buying public...who dont want to mess with recharging stuff. For someone who is looking for weight reduction, it can be easily done, although at the expense of capacity.


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## ukbloke (Sep 1, 2007)

The wireless solution is pretty straightforward. Watch-type batteries in each shifter with something like an ANT+ wireless transmitter - this is no more complicated than a Garmin cadence sensor. Larger capacity battery with a control unit mounted near the FD, with a single additional wire run back to the RD.


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## Full_Spectrum (Oct 30, 2012)

ukbloke said:


> The wireless solution is pretty straightforward. Watch-type batteries in each shifter with something like an ANT+ wireless transmitter - this is no more complicated than a Garmin cadence sensor. Larger capacity battery with a control unit mounted near the FD, with a single additional wire run back to the RD.


Actually that would add significant complexity to the system with no real benefit.
You would need 2 batteries for FD and 2 batteries for RD in your system. Not every application is suitable for a wireless solution- and this may be one of those applications.


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## ukbloke (Sep 1, 2007)

Full_Spectrum said:


> Actually that would add significant complexity to the system with no real benefit.
> You would need 2 batteries for FD and 2 batteries for RD in your system. Not every application is suitable for a wireless solution- and this may be one of those applications.


Maybe I didn't explain it right. One rechargable battery connected to both FD and RD. Running one wire along a chain stay is no big deal. Hiding the battery and making the derailleurs look less ugly is a bigger challenge IMHO. Watch-type batteries in the shifters, which last for years before replacement, like many other existing wireless products today.


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## Full_Spectrum (Oct 30, 2012)

ukbloke said:


> Maybe I didn't explain it right. One rechargable battery connected to both FD and RD. Running one wire along a chain stay is no big deal. Hiding the battery and making the derailleurs look less ugly is a bigger challenge IMHO. Watch-type batteries in the shifters, which last for years before replacement, like many other existing wireless products today.


Understood. Unfortunately, any wireless protocol that I am aware of would require significantly greater capacity than any watch type battery can offer. Keep in mind that the wireless devices would need to remain "always on", unless you added some way to disconnect them...which would again add to the complexity, and weight.

Designing a system isnt the difficult part here. Keeping the system easy to manufacture, package, ship, sell, install, and maintain is what is involved. If you could even figure out a way to do all of this with commercially available technologies- it would be far beyond the price barrier for which any person would be willing to pay. Just my opinion.


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## ukbloke (Sep 1, 2007)

Full_Spectrum said:


> Understood. Unfortunately, any wireless protocol that I am aware of would require significantly greater capacity than any watch type battery can offer.


You should check out ANT+ Sport. Garmin have been delivering affordable wireless fitness products using this for about 5 years. Cadence sensors, speed sensors, heart rate monitors, power-meters, etc. all running for multiple years on watch/hearing-aid type batteries. The wireless IC costs less than $1 in volume. There are huge numbers of products using this. Low-power Bluetooth is another solution starting to ramp up right now. It would be easy to put this into a shifter. The wireless transmitter only needs to be powered up when you are shifting, so power can be conserved for very long periods of time. There will be a shifting lag due to the electroncs but it can be minimized with good design - I will admit that I do not know what the signal lag is with ANT+ Sport, maybe it is high enough to make this harder than it seems to me.


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## Full_Spectrum (Oct 30, 2012)

ukbloke said:


> You should check out ANT+ Sport. Garmin have been delivering affordable wireless fitness products using this for about 5 years. Cadence sensors, speed sensors, heart rate monitors, power-meters, etc. all running for multiple years on watch/hearing-aid type batteries. The wireless IC costs less than $1 in volume. There are huge numbers of products using this. Low-power Bluetooth is another solution starting to ramp up right now. It would be easy to put this into a shifter. The wireless transmitter only needs to be powered up when you are shifting, so power can be conserved for very long periods of time. There will be a shifting lag due to the electroncs but it can be minimized with good design - I will admit that I do not know what the signal lag is with ANT+ Sport, maybe it is high enough to make this harder than it seems to me.


Right- but there is the other side of the BT connection to deal with.The Garmin needs to be recharged regularly especially when using BT or ANT+ devices.
And, it adds unnecessary complexity, additional weight, and a potential point of failure into the system, which is already heavier that the mechanical version.
Sounds like a good idea though. Let me know when youve worked it out so I can buy one.


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## ukbloke (Sep 1, 2007)

Full_Spectrum said:


> Right- but there is the other side of the BT connection to deal with.The Garmin needs to be recharged regularly especially when using BT or ANT+ devices.
> And, it adds unnecessary complexity, additional weight, and a potential point of failure into the system, which is already heavier that the mechanical version.
> Sounds like a good idea though. Let me know when youve worked it out so I can buy one.


The other side is no big issue either - similar power consumption to the shifter electronics for the wireless IC, and you have the rechargeable battery to draw the power from. Garmin head units need frequent recharging because of the screen, the processor to do all the math, the memory and the GPS. Supporting the wireless devices is a relatively small part of their power budget.

I'd love to work on this stuff. I could imagine splicing the wireless components into the existing Di2 components as a proof of principle. Unfortunately, I have a day job, and the only company that will make money out of this is Shimano. They can simply wait until they need to invent something "new" to make everybody go and buy another round of component upgrades.


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## blairellis (Nov 9, 2012)

Great looking bike! Love the Di2 integration!


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