Di2 battery suddenly died.

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Drizt
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Re: Di2 battery suddenly died.

Postby Drizt » Mon Sep 28, 2015 10:10 pm

Drugs are bad, mkay

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hamishm
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Re: Di2 battery suddenly died.

Postby hamishm » Fri Nov 02, 2018 12:24 pm

This just started happening to me with my 6770. I've had the battery completely discharge three times in a couple of weeks in the last month (meaning, nothing shown at all when trying to check the battery level). I've got two batteries and it happens with both, so that's one thing ruled out.

Last Sunday I rode and the battery status was a solid green. By Wednesday night it was a solid red.

The only idea I've got is that about 5-6 weeks ago, I had a minor off and landed drive-train side down. Shifting is still great, but maybe the RD took a knock? And maybe I had one or two unexplained chain jumps, not really sure.

People on other forums talk about checking your limit screws in this case, in case the motor is constantly engaged trying to change the gear. I never leave the bike at the extremes of the cassette, so that doesn't seem like it.

Any thoughts?

Hopefully there's a fix, don't really want to spring for a R8000 upgrade...

ironhanglider
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Re: Di2 battery suddenly died.

Postby ironhanglider » Fri Nov 02, 2018 1:10 pm

hamishm wrote:This just started happening to me with my 6770. I've had the battery completely discharge three times in a couple of weeks in the last month (meaning, nothing shown at all when trying to check the battery level). I've got two batteries and it happens with both, so that's one thing ruled out.

Last Sunday I rode and the battery status was a solid green. By Wednesday night it was a solid red.

The only idea I've got is that about 5-6 weeks ago, I had a minor off and landed drive-train side down. Shifting is still great, but maybe the RD took a knock? And maybe I had one or two unexplained chain jumps, not really sure.

People on other forums talk about checking your limit screws in this case, in case the motor is constantly engaged trying to change the gear. I never leave the bike at the extremes of the cassette, so that doesn't seem like it.

Any thoughts?

Hopefully there's a fix, don't really want to spring for a R8000 upgrade...


First up I know nothing about changing gears with electrickery. However if the limit screw theory is true then your front derailleur is potentially at one extreme or the other (depending on trim adjustments) and that might be a source of such an issue. Does that mean you should leave your bike cross-chained when stored? It seems unlikely since I've not heard anyone advocating this before.

My first inclination would be some sort of short-circuit or partial connection caused by dirt/corrosion. Therefore I'd check all electrical connections from the battery to the switches to the derailleurs.

The unexplained chain jumps may well be related, however I assume that you have eliminated mechanical issues like a stiff link first.

Cheers,

Cameron
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jasonc
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Re: Di2 battery suddenly died.

Postby jasonc » Fri Nov 02, 2018 1:20 pm

hamishm wrote:Any thoughts?


charge the battery, unplug the RD. leave it a few days. if it remains at 100% then it's the RD
rince, repeat with FD, then each shifter individually
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Toyopet
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Re: Di2 battery suddenly died.

Postby Toyopet » Fri Nov 02, 2018 9:42 pm

hamishm wrote:.....Any thoughts?

Hopefully there's a fix, don't really want to spring for a R8000 upgrade...


I had a similar problem a year or two ago, with my 2011 vintage 6770 Di2. After much testing/disconnecting/mucking around, I put it down to the front junction unit and gear trim controller (SM-EW67). I think it had been out in the sun and wet weather too much, resulting in the seals failing and enough water ingress to cause slow leakage which was slowly flattening the battery. After installing a new junction unit, it’s all good now. (only ~$50 for a new unit)

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Duck!
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Re: Di2 battery suddenly died.

Postby Duck! » Sat Nov 03, 2018 8:07 pm

First up, the limit screw thing.... Di2 derailleurs have a slight overshift on each gear shift to ensure a proper shift, before centring under the sprocket. Therefore the limit screws need to be set so there's about 1mm between the screw tip and the limit stopper at each end of the range to allow the overshift. Doesn't matter if the bike's parked in an extreme gear or not, if the derailleur is blocked by poorly-set limits in normal use, it will rapidly discharge the battery. Beyond that, it's a process of elimination to find a component that's not properly going into sleep mode and continually drawing power. As suggested above, it's a matter of testing with one component at a time disconnected and seeing if there's a change in the discharge rate, but just a tip, if it's an external battery system, there's a fair chance the battery mount is the problem part - I've had a fewover the years with the same problem tracing back to the mount.
I had a thought, but it got run over as it crossed my mind.

lone rider
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Re: Di2 battery suddenly died.

Postby lone rider » Sun Nov 04, 2018 10:14 am

Must be gremlin season..

Also still have a 6770 setup on 1 bike which hasn't skipped a beat until this weekend. So I washed the bike during the week, fitted some new wheels and changed brake pads after the clean and checked the gears were all good so everything was still working fine. Went to ride it yesterday and nothing, no lights on junction box. Re-charged battery, still nothing, checked battery with mutilmeter, its fully charged. I have a old battery holder and have checked the system with both, still nothing. Started pulling things apart, bb is out, wiring is all good, no signs of corrosion anywhere. I thought to bypass the deraileurs and inner frame junction, so I took a cable and connected battery straight to handlebar junction box, still no lights. Am I right in thinking the junction box should still power up without any other connections?

Mike Ayling
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Re: Di2 battery suddenly died.

Postby Mike Ayling » Mon Nov 05, 2018 9:40 am

Just as I was thinking that if I ever give up my Rohloff hubs for a derailleur bike that Di2 would be a much better alternative than those stretchy, stick derailleur cables, but after reading this thread I will stick to Rohloff!

Mike

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