Di2 not working

[kookmyers]

I picked up a bike with DA Di2 7970 a few weeks ago. I suited up for my ride to work this morning, got a block away from home and when I tried to shift nothing happened. I tried the front junction and got no response and tried holding a shift button with no response.
It worked last week. Over the weekend I did charge it and in case it is relevant, I charged it overnight. I recall that the charger light was green when I first plugged it in. I plugged it in again and the LED did not light. I took the battery out of the seatpost and found I do not have a Shimano battery. I checked online and did not find what I have. The 2 pin connector was installed just outside the seatpost and the 4 pin connector is mated inside the frame. I was not able to measure a voltage across any of the pins.

[jpritchet74]

This is just one of the reasons that I went from electric back to mechanical. Tracking down problems can be a pain. Been there, done that. Don't ever want to deal with it again.

Since your battery is aftermarket it could be a problem with the connection from the wiring harness to the aftermarket connection. That is where I would look first.

All problems that I have had with Di2 have come from soldered connections needing to be re-soldered. When done correctly they shouldn't fail, but most people don't do it correctly or protect the connection correctly.

[BdaGhisallo]

This is just one of the reasons that I went from electric back to mechanical. Tracking down problems can be a pain. Been there, done that. Don't ever want to deal with it again.

Since your battery is aftermarket it could be a problem with the connection from the wiring harness to the aftermarket connection. That is where I would look first.

All problems that I have had with Di2 have come from soldered connections needing to be re-soldered. When done correctly they shouldn't fail, but most people don't do it correctly or protect the connection correctly.

It seems that the issues derive from the customization of Shimano's design and not something that is native to the Shimano product. DI2 is very reliable when you stick with it as Shimano designed and built it.

Let's also keep in mind that 7970 was the first generation of DI2 and its unique wiring protocol was abandoned by Shimano in 2012 and the whole DI2 lineup adopted the E-Tube protocol.

[d_douglas]

I am interested in Di2 for a new bike, but this is what worries me about Di2. If I stick with Campy mechanical, nothing can go wrong!

[jpritchet74]

I am interested in Di2 for a new bike, but this is what worries me about Di2. If I stick with Campy mechanical, nothing can go wrong!

Yup. Campy mechanical for me. And aside from the possible electrical shifting "problems" (such as failed custom connection on that 1st generation Di2) you don't have to worry about a battery dying because you haven't charged it in weeks.

[CiclistiCliff]

Guys, Di2 is more reliable than anything else unless you have ‘custom’ bits.

It’s like complaining that Campy shifting sucks after hooking up a SRAM rear derailleur to SR shifters

[old fat man]

Shimano was pretty quick to abandon the 7970 wiring. You should too. I'd go to mechanical or invest in current edition Di2

[peanutgallery]

Looks like a shade tree mechanic got ahold of that setup

[pasadena]

just buy a new shimano battery or another cheap ebay battery and rewire it.

The previous owner should have told you about the aftermarket battery and wiring.
Probably modded as a cobbled together setup to save money.

the battery is probably toast or the connections are faulty. Either way, starting fresh is better than constantly hassling with it.

[kookmyers]

Thanks everyone. The battery is the problem. I am working on a repair attempt.

[BdaGhisallo]

Guys, Di2 is more reliable than anything else unless you have ‘custom’ bits.

It’s like complaining that Campy shifting sucks after hooking up a SRAM rear derailleur to SR shifters

You've nailed the crux of the matter.