Shimano Di* do and do not.

[grantxdavis]

Hi, just looking through your posts, good work.

Just a quick question, is it possible to splice into a ISMEW79A-E wiring kit without the use of sti levers? Basically I want to set up my TT bike with Di2 but cannot find a ISMEW79A-I front wiring kit, so I am thinking of using the E harness to power the shifters in the aero extensions and then somehow splice some custom shift buttons that I can mount on my base bar.
Thanks

 

[Mr Haematocrit]

What Di2 are you going to be running 10 speed Ultegra, 10 speed Dura-Ace, 11 speed Dura-Ace

 

[redcard]

V, any idea when Ultegra di2 will be updated, and what we could expect from the next version?

 

[grantxdavis]

Sorry, I should have mentioned that,
I'm looking at 7970 DA

 

[Mr Haematocrit]

V, any idea when Ultegra di2 will be updated, and what we could expect from the next version?

I've not heard anything about next gen Ultegra release dates or specification at this time, but I have my name down for it when it finally gets here. Im hoping its a evolution of the latest Dura-Ace as was the case for the 10 speed models.

 

[Mr Haematocrit]

Sorry, I should have mentioned that,
I'm looking at 7970 DA

The 10 speed 7970 Dura-Ace is the best and most hackable Di2 imho... Although you can splice the loom its not my prefered option unless it can not be avoided. I generally buy looms and cut them up for the connectors required for modifications.
If I was appoaching this I would modify the front of it by the display to have multiple plugs, and then build your custom buttons and shifter solution as plug in components, its a more effective way to work imho as if you splice and solder and have problems addressing them is a nightmare.. make the system modular.
If your Di2 hacking you can never have to many extra plugs, it starts off with custom shifters, then a seatpost battery and then... buy a complete loom to tear apart, you will not regret it imho

If you want help with it message me a drawing or photo of component placement desired and I will do a parts list for the way I would undertake it

 

[grantxdavis]

Thanks V,
I haven't yet purchased parts, I am still looking into what I can do with the bits an pieces I can find. I am shopping around for the best prices.
A permanent connector based system would be ideal, but how exactly would the modified plugs plug into the front wiring harness?
And then on the other hand I don't mind splicing into the front wiring harness, if I do mess it up they are not too expensive. I am an electrician by trade so fancy myself wiring things-famous last words!
I was mainly concerned with if it would actually work. I assume that a second switch spliced into the correct cable before the junction would just send the same signal to the junction then to the RD- telling it to shoot, regardless of which switch actually sent the signal. Is that correct logic?

 

[grantxdavis]

*shift

 

[Mr Haematocrit]

Your logic is most certainly correct and this thread has a wiring diagram earlier on which is worth a review. The way I approach things such as this is to make a little 'Y' shape connector.. in a sense three plugs joined, so you would plug one into the main loom and the other two used to plug in the two sets of shifters you wish to use. (like a multi-plug) The advantage of doing it this way imho is that should you ever need to move the system from one bike to another or remove it for maintenance then you only have to modify the 'Y' connector.
From my experience splicing it can impact you in ways you do not think, such as if you change your stem or bars, you may not have the wiring available to remount the shifters as you desire. When this happens you have to rejoin everything. Im not a fan of putting hot soldering irons near my carbon frame so like being able to remove the 'Y' shape and extend that a little if needed (it's just safer for me)
Im not an electrician so I hope my soldering skill set is not of the standard of yours, so you may feel more comfortable modifying the loom itself and the possibility of having to this when its installed on the bike.
When I get home tonight I will let you know the part number of what I buy as this gives a vast number of plugs and permits a great deal of flexibility for other things you may wish to do at a later date such as hidden battery's, power for lights etc..... The possibility's for someone with your skill set is pretty extensive imho

 

[grantxdavis]

The possibility's for someone with your skill set is pretty extensive imho

Don't give me a big head haha
I said that only to show that im not afraid to solder.
Yes the Y plug does sound like the best option, but i am having trouble imagining it. Your help is greatly appreciated.

 

[marty5P]

What Di2 are you going to be running 10 speed Ultegra, 10 speed Dura-Ace, 11 speed Dura-Ace

Hi There, A few months ago I went to go for a ride and my Ultegra Di2 was flat. It had not been long since last charge. Over the next few weeks I found the battery would be flat after 3.5 hours after a full nights charge. I took it to the bike shop and they ran the diagnostics and did a series of disconnections to isolate the problem. They identified that the left brake lever must have had a short and replaced it. I got the bike back after 2 weeks and the battery drained overnight from full to zero without riding at all. Its now back at the shop but everyone is scratching their heads!

Has anyone come across this? We have tried numerous batteries in the unit and they all drain.

 

[Mr Haematocrit]

I have never ever heard of a shifter having an electrical short and still functioning, this is a symptom of the problem rather than the actual issue itself.
Imho going by what you have stated I would think that the loom itself is the problem. I would think the bike has a internal loom would this be correct? - can you provide any information about the bike (make/model - Carbon/Ally frame), Di2 installation and the last time you rode the bike without problems. (what was the weather like, distance approximately etc)

 

[marty5P]

It's a Bianchi Sempre carbon frame with internal cabling. I've only had problems on two rides. More times not actually getting out he door as is dead.

Rid one - fine day, 3.5 Hours into the ride the power goes. I was only 1 km from home so didn't worry too much.
Ride two - started dry, 1 hour into ride it rained heavy. Power went off but kept riding with bunch in reasonable gear. Power came back 10 minutes later. Still raining but not as heavy. Power stayed on till end of ride, approx 3 hours.

Can't think of anything else strange.

 

[dodgy]

Saw these same symptoms on a thread on BikeRadar, the poster ended up replacing the battery holder, his LBS figured out that's where the drain was happening.

 

[Andrew_P]

I have seen Ultegra Di2 Groupsets discount to a tad over 1k, are they good value?