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Discussion Starter · #1 ·
I purchased a new bike about 45 days ago and this is the third time I had to recharge the Shimano controller.

The first time was a learning experience. The shop told me they charged it and they showed me that the battery was "Green" when they held the shifter. But, I had about 150-200 miles and then it died.

The second time was about 100 miles and the third time... I gave it a full charge but I went away from work for 2 weeks and then I rode it for 30 miles and the battery died again.

During the second and third time, I noticed that the battery indicator would go "non-blinking red" and then do a "green and red light". Is that a code of some sort?

Im trying to understand if Im performing the charge incorrectly? I am plugging it directly to my computer and letting the e-tube app charge it for overnight. Or should I just be going directly from an "iphone transformer" to the controller? Either way, after the first time, I checked the battery status after an over-night charge and the battery was green in the morning but it just quickly became red.
 

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Sounds to me like the rear limit screw on your rear mech is set wrong. More on that later.

As for the lights, it's what they do now.

Press and hold a shift button and first the battery indicator lights up. Green, blinking, red or blinking. You know that one. Second though pops up the synchro-shift indicator lights. Solid red/green for manual or one blink or two blinks for synchro one or two.

So you get the battery indicator followed by the synchro-shift indicator.

You change synchro-shift modes by double tapping the button, so don't ever double tap the button by accident now.

You are charging correctly, that part is pretty hard to mess up. What's going on is a parasitic drain.

Now, to limit screws.

Di2 limit screws are in no way the same as mechanical and should never be treated as such. We're going to focus on the low one here. I suspect yours in turned in too much. When this happens, the mech cannot go as far as it wants up the cassette and gets locked in trying to do so, draining your battery.

The correct way to set the limit screw is to put it into first gear (little ring and biggest cog) and back out the low limit screw, then tighten it until it barely touches the metal plate, then back it off about a half millimeter or so. It cannot be touching.

I suspect your limit screw is touching the limit plate, this causes the battery to drain very fast, exactly like you are experiencing.
 

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Interesting that the Shimano manual just asks for that limit to just touch. No mention of the 1 mm backoff you describe. The manual does ask for a one turn backoff at the other limit.

Sent from my SM-G900W8 using Tapatalk
 

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Discussion Starter · #6 ·
If you just bought the bike, take it back to the shop. Let them check the derailleur setups. Otherwise, you may have a bad battery.
I did that. So, Im without a bike for a bit. But I just wanted to understand from a ignorant (dont know how to fix chit myself) point of view and MMsRepBike explained it well!
 

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Discussion Starter · #7 ·
Sounds to me like the rear limit screw on your rear mech is set wrong. More on that later.

As for the lights, it's what they do now.

Press and hold a shift button and first the battery indicator lights up. Green, blinking, red or blinking. You know that one. Second though pops up the synchro-shift indicator lights. Solid red/green for manual or one blink or two blinks for synchro one or two.

So you get the battery indicator followed by the synchro-shift indicator.

You change synchro-shift modes by double tapping the button, so don't ever double tap the button by accident now.

You are charging correctly, that part is pretty hard to mess up. What's going on is a parasitic drain.

Now, to limit screws.

Di2 limit screws are in no way the same as mechanical and should never be treated as such. We're going to focus on the low one here. I suspect yours in turned in too much. When this happens, the mech cannot go as far as it wants up the cassette and gets locked in trying to do so, draining your battery.

The correct way to set the limit screw is to put it into first gear (little ring and biggest cog) and back out the low limit screw, then tighten it until it barely touches the metal plate, then back it off about a half millimeter or so. It cannot be touching.

I suspect your limit screw is touching the limit plate, this causes the battery to drain very fast, exactly like you are experiencing.
Thank you so much for the "break down" of understanding. Ive re-read the manual but was just a bit confused. I did take it to the shop but instead of going to the shop of purchase... I went to a different shop, same chain, and hopefully they will be able to discover something. At least, I can point them in the direction you explained and get it fixed permanently. Of course, there is a chance of a bad battery too.
 

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Please be sure to update us

Thanks
I had exactly the same problem and in my case it was a case of bad firmware and a bad junction box that were preventing the whole system to sleep, so it kept draining the battery even when not in use.
After a firmware update on all components and a new junction box, all good.

Sent from my SM-G925F using Tapatalk
 

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I had exactly the same problem and in my case it was a case of bad firmware and a bad junction box that were preventing the whole system to sleep, so it kept draining the battery even when not in use.
After a firmware update on all components and a new junction box, all good.

Sent from my SM-G925F using Tapatalk
I have had two issues with premature battery drain over my eight years of riding DI2. One was a bad external battery mount and the other was a bad front junction box like you had. If the limit screws prove not to be the issue, that's where I would check next.
 

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Discussion Starter · #11 ·
I had exactly the same problem and in my case it was a case of bad firmware and a bad junction box that were preventing the whole system to sleep, so it kept draining the battery even when not in use.
After a firmware update on all components and a new junction box, all good.
I got the bike back today... and the shop told me they "spoke to" Shimano and what I understood was that they asked to update the firmware specifically for the battery? I can totally understand firmware updates and just bad juju (heck, my professional career is based upon fixing firmware updates on hardware devices) so he stated the charge took 6 hours to complete and waited. 48 hours later... the battery still had 100% charge.

So, since im hyper aware of the battery status... ill take some notes and tomorrow ill find out what firmware version is currently on the device. Ill try to log on how long, I can only perform time measurement via miles, and see when the battery gets to Green to flashing to red to flashy red. Just in case it is a bad junction box or battery.

@leopafe... That pretty much sounds exactly what im experiencing. Battery drain even when Im not using it.

@MMsRepBike... would the limit screw cause battery drain only during rides or even when not in use? Just to gain future knowledge about DI2 systems...
 

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Discussion Starter · #13 ·
Day +4 And Ive done almost 75 miles and its still "green" non-flashy. So, maybe they played around with the limit screws but are not saying it or not... but they did confirm that they upgraded firmware. So, I guess its looking like bad firmware at this point.
 

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Day +4 And Ive done almost 75 miles and its still "green" non-flashy. So, maybe they played around with the limit screws but are not saying it or not... but they did confirm that they upgraded firmware. So, I guess its looking like bad firmware at this point.
Might be a first for me.

Heard of bad this or that, junction or battery or holder or whatever, but I don't think I've seen battery drain specifically due to firmware. Seen lots of other firmware issues.
 
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