Di2 Battery Position

[PaulSB]

A friend has a problem with her Di2 not charging, no light showing etc. Nothing happening at all.

During discussion on this I discovered the battery is installed in the seat post. A cable runs from a charging point in the right hand bar end to the battery.

If the battery is small enough to install in the seat post would it not make more sense to use a slightly smaller battery and place it in the bar end?

I should add I've never seen the battery. Is this the usual position for the battery?

 

[Venod]

I should add I've never seen the battery. Is this the usual position for the battery?

I don't have Di2 but I have just bought a new to me seat post for my Cannondale Synapse and it has a battery housing at the bottom.

 

[fossyant]

The battery packs come in specific sizes. She could have a break in the charge cable. Might need a good strip down and bench test.

Most common places are seat tube or seat post for road bike Di2

 

[PaulSB]

@fossyant very much agree re diagnostic test. Another friend tested the battery last night and got a figure of 5 volts, apparently it should be 7.5. The thought is either a duff battery (only 10 months old) or a damaged cable.

I've just been able to arrange a diagnostic test at our LBS. My friend works.

I've no experience of Di2. I had imagined there is a wireless signal from the controls to the chain ring/derailleur. It's beginning to sound to me as though the signal travels down wires? Or have I got it completely wrong?

 

[fossyant]

It's all wired with Di2, so either duff battery (which will be in warranty) or a damaged cable.

 

[Milkfloat]

Di2 is not wireless in anyway unless you add on the module that gives to Ant+ or Bluetooth to your head unit/phone. Even then you need cables to the shifters, mechs and junction (bar end mount in your case). If there are no lights at all then I guess it is a connection issue from bar end to battery. The LBS will sort that out, but in the meantime you could check to make sure the connections are fine.

 

[themosquitoking]

If there is only one connection to the battery and the system shifts ok then that connection isn't the problem. I would then look at the charging cable part of it. Check the charger you are using charges something else first and then try a different charger for the di2.

 

[PaulSB]

Apparently the battery is shot and will be replaced under warranty.

Thanks for the remarks, I've learned a little in the last 24 hours. Di2 clearly works a little differently to how I had imagined.

I have vaguely toyed with having it on my next bike but after my friend's experience it is definitely off the spec list. I know a few people who've had minor issues but have always got home and been able to ride again in a day or so.

My friend encountered this problem on Saturday, she hopes to have her bike back next Monday. That's 10 days without a bike because of a duff battery. To me it doesn't matter how good it is, ten days without the bike is simply too long.

My Wahoo was replaced in five days for having a duff battery!!

 

[T.M.H.N.E.T]

It's complicated but also not. The bar end junction box has 2 ports - rim brake shifters have 3 so you can add sprint buttons/climbing button/Hydro 2

Shifter <Cable> Junction Box - Junction box <Cable> Opposite shifter - Opposite shifter <Cable> to BB junction box (4way)

<Cable> rear derailleur
<Cable> Front Derailleur
<Cable> Battery