Di2 battery suddenly died.

[Arlberg]

My Ultegra DI2 system has been faultless for over two years, but last week I went out only to find the battery was completely dead. I thought it was strange at the time because I hadn't ridden much since I last recharged, or seen the flashing green light or the red light indicating it was getting low.

Anyway I recharged it and made sure I had a full green light when I reinstalled it to ensure it had charged fully. The next morning I checked the battery and I still had a full green light, and I went for a short ride. That was 4 days ago. However this morning the battery was completely dead again. So the battery has drained completely from near enough to full to completely flat inside of 4 days, despite the bike not being used in that time. The battery is either not holding its charge/ie dead, or there is something draining the battery somewhere in the bikes Di2 system.

I have probably only recharged this battery 8 times or so in the past two years so I can't imagine the battery is worn out. It seems to have very suddenly developed a fault. It has always been looked after, it has never been dropped or anything.

Is there a way to determine if the problem is caused by a fault in the battery or a fault/leak in the Di2 electronics without having to buy a new battery straight up? I don't particularly want to spend $80 or so on a new battery when the fault may not be with the battery.

What I am certain of is that neither the battery or the electrical system of the bike has ever got wet, ever, as I have never ridden in the rain since I've had it.

Can the Di2 diagnostic tool that some bike mechanics have in their workshops isolate an electrical leak or the the problem to a certain part, whether it be the battery or otherwise?

And are most bike mechanics as good with an amp meter as they are with a spanner, or do I need to go to a specialist bike mechanic, almost a bike electrician (!) to get this fixed properly?

Finally can anyone recommend a good Di2 mechanic on Sydney's lower North shore / beaches area?

[Quency]

I experienced a similar problem on my Ultegra di2.
Went to go for a ride and found the battery dead. Recharged not thinking anything of it. A couple of days later found it dead again.
Got the firmware updated by my local bike shop but it didn't solve the problem. the diagnostic software didn't identify the fault either.
Not wanting to be out of pocket for a new battery either, I went through an elimination process to find the fault. basically recharge the battery and unplug 1 part of the system and see if the battery drains. if so, recharge and repeat, unplugging a different part of the system. took a couple of weeks, but I eventually narrowed it down to the battery holder (I have an external battery holder). I got the faulty part replaced under warranty (bike was only 6 months old) and it has worked flawlessly ever since.

I imagine you would need to borrow another battery to see if the battery is the problem. your LBS may be able to help you out there.
Elimination process (as noted above) may help you identify a fault elsewhere if you have the time and the patience
Beyond firmware updates and tuning, i'm not sure what capability bike shops have to repair a faulty part or if it all goes back to shimano. luckily mine was a replacement under warranty
Can't help recommending a bike shop in your area; I'm in Newcastle

[Arlberg]

Thanks Quency for your comprehensive answer.

I will do what you suggest. In fact I have already started. I have recharged the battery and unplugged the rear derailleur, and I will wait a few days then check the charge. Two days should be enough time to see if the indicator light flashes green or even turns red or does nothing anymore in that time. If it doesn't I will recharge again and unplug the front derailleur.

I am surprised to hear the batter holder drained your battery (I have an external battery as well) as I didnt think it would draw any power? What was wrong with it? Could corrosion be a cause? Did you see any corrosion etc on the terminals etc when you replaced it?

Can I assume that the shifting levers/buttons would not be a possible cause, because as far as I know they also don't draw any power? Unless they are corroded too which I doubt very much.

I have also bought a new battery just in case, as I found a new one on ebay for $61 delivered. I can always resell it or keep it as a backup if the existing battery turns out not to be faulty which I'm pretty sure it isn't.

If it's not the front or rear derailleur, or the battery holder causing the battery to drain, and the new battery also drains quickly what else could cause this?

[Quency]

Yeah I was surprised it was the battery holder too. I'm mostly a fair-weather rider and hadn't ridden the bike in the rain so i'm doubtful it was corrosion of the terminals; and I didn't notice anything there. all the connections looked fine. I am inclined to think it was a loose wire between the terminals or something causing a short. I didn't have a chance to get too far into that though as it was replaced under warranty and I was happy enough to be riding again.

Unplugging the top junction box during the investigations, I was able to eliminate both shifters and the junction box as the cause in one go. However, given the battery holder was the cause and seemed unlikely, I would be hesitant to rule anything out.
at the time, LBS advised that front or rear derailleur not going into "Sleep Mode" was the most likely cause.

At about the limit of my experience here so i'm not entirely sure what else could cause a drain. if you get through each individual part and have no success identifying the problem, I guess take it to the LBS and see what they can do? a firmware update may be helpful in your case?
Hope you get it sorted

[Duck!]

I've had the same thing on bikes through work a few times. Absolute pig of a thing to diagnose because the E-Tube diagnostics will only pick up if a component is actually malfunctioning, & not see if there's a current leak that isn't otherwise affecting function. Staggered eliminato is the only way you can narrow it down, and as Quency suggested, you can speed the process by disconnecting the top half of the system. If the power doesn't drain, you hook the top end back up & disconnect the derailleurs, and test each shifter.

Or to save you a lot of faffing around, based on past form I would go straight to the battery mount - each system I'v had this problem with has been a bodgy battery mount. I don't know the electronogical ins & outs, that area is well outside my expertise, I handle mechanical stuff, but the thing (well, all of the components really) is considerably more complicated that it first appears. It's not simply the battery attachment point, it contains a substantial amount of the system's brain power. Why this component is more prone to problems than the others I do not know.

[Arlberg]

When you say Quency 'Unplugging the top junction box' and Duck! 'disconnecting the top half of the system' do you mean unplugging the connection on the little box with the battery indicator lights? If I do disconnect that how do I check if the battery has gone flat or not as the LED battery indicator lights themselves will be disconnected from the battery?

[Duck!]

When you say Quency 'Unplugging the top junction box' and Duck! 'disconnecting the top half of the system' do you mean unplugging the connection on the little box with the battery indicator lights? If I do disconnect that how do I check if the battery has gone flat or not as the LED battery indicator lights themselves will be disconnected from the battery?

Yep, unplug the cable from the junction. Leave it overnight, then reconnect & check the battery.

[Arlberg]

Update. 24 hours after I fully recharged the battery and disconnected the rear derailleur I still had a solid green light on the battery indicator. 36 hours after however I had a flashing green light indicating I was below 50% charge.

Taking Duck!'s advice I will concentrate now on the battery holder. I have recharged the battery fully again and disconnected everything else, being the junction box (and therefore both shift levers) the front derailleur and the rear derailleur. So should the battery go flat now, the battery holder can be the only cause.

I still don't understand how the battery holder (with no components connected to it) could make the battery go flat. If there is nothing connected to the battery at all, what is drawing the power and causing it to go flat? Wouldn't it be the same test as just having the battery sitting on a table and seeing if it goes flat by itself?

[Duck!]

I still don't understand how the battery holder (with no components connected to it) could make the battery go flat. If there is nothing connected to the battery at all, what is drawing the power and causing it to go flat? Wouldn't it be the same test as just having the battery sitting on a table and seeing if it goes flat by itself?

As I said earlier, although it's a simple-looking thing, there is a considerable amount of the system's brainpower in there, and if something has gone a bit whoops it can still pull power even if everything else is disconnected.

[isabella24]

Mines done the same thing
I'd sent the battery back to the bike shop in Melbourne (I'm in Sydney) where I bought the bike 6 months ago before I saw this thread. So now I'm hoping it is the battery.

I've already waited 2 weeks for a new battery but according to the bike shop I'll have to wait until Shimano sends me a replacement to try. So no bike.
This seems a little poor for a shop I spent almost $9,000 with 6 months ago. Pity I don't live in Melbourne or I'd be paying them a visit.

[Arlberg]

Update. I recharged fully again and disconnected everything, the junction box and therefore both shift levers, and both derailleurs. So the only thing connected to the battery was the battery holder. After 36 hours, for the first time since this problem began I still had a solid green light. So it seems I can rule out the battery holder? I recharged again and reconnected both derailleurs and leaving just the junction box (and therefore both shift levers) disconnected. I was quite sure, given the above, that either the junction box or the gear shifters was the cause. However to my surprise, 36 hours later I had a green flashing light again.

The story so far...

Disconnecting only rear derailleur - battery showing significant drain after 36 hours.
Disconnecting everything (except the battery holder) - no significant battery drain after 36 hours.
Disconnecting junction box / shift levers - battery showing significant drain after 36 hours.

What conclusions can I draw from these results?

I have now reconnected everything and put in the brand new battery I bought on ebay. If it shows no sign of battery drain after 36 hours then can I assume the original battery itself is at fault? Maybe, but then if that was the case why did it not drain significantly when everything except the battery holder was disconnected?

Should the new battery drain significantly within 36 hours then the only other thing I can think of would be to recharge again and disconnect only the front derailleur?

[Duck!]

OK, so there are still some component isolations that haven't been tested yet, particularly involving the front derailleur. Try with that being the only thing connected past the battery mount, and then as the only thing not connected, and see what results you get.

[jerrah]

My Di2 battery draining was caused by a damaged cable. With all internal wiring it took a bit of finding to locate.

[toolonglegs]

And here in lies the difficulty with electronics... "the intermittent fault" .
Need to hook up a multi meter in between the battery and it's terminals and find out which part individually is sucking the juice. In theory pretty easy ... in practice possibly a pain in the butt.

[wombatK]

And here in lies the difficulty with electronics... "the intermittent fault" .
Need to hook up a multi meter in between the battery and it's terminals and find out which part individually is sucking the juice. In theory pretty easy ... in practice possibly a pain in the butt.

I wish it was that easy with cars that misfire intermittently ... after more than a dozen trips to three
different dealers and getting head office involvement, the only treatment that worked for me was to
sell it. Warranty ? Ha, what warranty !

[toolonglegs]

And here in lies the difficulty with electronics... "the intermittent fault" .
Need to hook up a multi meter in between the battery and it's terminals and find out which part individually is sucking the juice. In theory pretty easy ... in practice possibly a pain in the butt.

I wish it was that easy with cars that misfire intermittently ... after more than a dozen trips to three
different dealers and getting head office involvement, the only treatment that worked for me was to
sell it. Warranty ? Ha, what warranty !

Actually it isn't that different with cars or motorbikes ... a bit more complicated than just looking for a circuit fault, but not that much difference.

[Arlberg]

Thanks Duck! I will try that next, after I see what this new battery does.I am hoping I will still have a solid green light after 36 hours, indicating that the original battery was the cause. That will be the simplest (and cheapest) outcome.

I know nothing about electrical circuits. Just so I can understand what's happening here, can I assume that when everything is functioning properly and I'm not actually pushing a shift button/changing gears, there should be no power/current running between any of the cables, that the power/current (should) only start flowing when I push one of the shift lever buttons to activate a derailleur, and that this premature battery drain is occurring because the battery is continuing to supply current to a component that should be 'asleep' when the bike is at rest? If so then Toolonglegs suggestion is a good one, I could perhaps get an electrician to put a multimeter on the cable between the battery and each component and the meter would detect if there was power running through the cable when there shouldn't be, ie when no shift buttons are being pushed? That seems like a quicker and easier way to find what part(s) is draining power than the method I am currently using.

isabella24, as you can read the problem may not be with your battery, it could be a faulty component or cabling too. I just bought a new battery on ebay rather than wait indefinitely for a warranty replacement from Shimano when it may not even be the battery anyway.

[Newcastle Dave]

I had a similar issue about a year ago.

The di2 on my Cell Omeo died. I had been away for a week, jumped on the bike and no power. I put it on the charger thinking maybe I had drained it, but after charging for several hours it still showed nothing. I took it to a LBS who run some diagnostics, plugged in another battery and confirmed the only thing wrong was the battery was dead.

I then said I would have to send it to Cell for warranty, and they said that they were sure Shimano would replace it, no questions asked. He hinted that it happened more often than Shimano would like to admit, so they would replace it quickly and without fuss.

After I contacted Cell, they said to just send the seatpost back to them (and enclose a receipt for the postage) . Less than a week later I had the seatpost back with a new battery (and the postage refunded) and haven't had a problem since. So not sure if it was cell or Shimano to thank (or both), but no complaints from me for the service.

[jasonc]

my internal battery died a couple of months ago. A mate has the pce-1 thingy which was useless. he also had a spare battery. The diagnostic thingy said everything was hunky doory. yeah right. unplugged my battery. plugged in his. worked perfectly. I ordered a new battery and gave mine to a mate who works at a LBS. new battery installed. warranty replacement sold.

[Arlberg]

Obviously a dead battery simply doesn't work, but what are the symptoms of a dying battery or a battery thats on the way out, apart from a shorter life between recharges?

For example I notice that when I recharge this potentially faulty battery (I first plug the battery into the charger and then turn on the pwoerpoint) it takes a long time between turning on the powerpoint and for the recharging LED indicator on the charger to come on indicating that the battery is indeed charging. Sometimes this can be 20 minutes or more. Sometimes when this happens I turn off the power at the powerpoint, take the battery out of the charger, wait 30 seconds or so and push it in again, turn on the powerpoint again and the LED usually (but not always) comes on immediately. I thought maybe I had not inserted the battery into the charger correctly the first time, but I definitely always have.

[Duck!]

That's weird. The normal dud battery indicator is a red light on the charger.

[isabella24]

isabella24, as you can read the problem may not be with your battery, it could be a faulty component or cabling too. I just bought a new battery on ebay rather than wait indefinitely for a warranty replacement from Shimano when it may not even be the battery anyway.

My battery is the new Di2 internal seatpost one BTR2? They go for about $160-$180 and I didn't want to stump up for that amount of money when the battery and entire bike is only 6 months old and under warranty!

I got an email today from the bike shop saying they have received a replacement from Shimano and are going to put it in the mail for me today, so the process has currently taken about 2 weeks. With any luck, I might get it by the end of this week and be able to try it. Hopefully it will fix the problem, but if not, I might have to package the entire bike up, send it back to Melbourne and get the shop to fix it under warranty.

I'm really hoping it doesn't come to this, but an expensive 6 month old bike which has been lucky to do over 1000kms should not be breaking down like this. I've been trying to help the shop by removing the battery myself, sending it down there etc, but if I can't fix it, they need to honour their warranty.

[jasonc]

That's weird. The normal dud battery indicator is a red light on the charger.

that's what i got. but of course i wanted to rule out the junction box.

[isabella24]

And as an aside, thanks for sharing your situation Arlberg, as I am learning lots more about potential courses of action if the battery replacement doesn't work!

[Arlberg]

Funny, I have never had that red LED light come on during recharging indicating a faulty battery. Regarding the (sometimes long) delay between me turning on the power and the recharging LED light coming on, I was wondering if it could indicate a fault in the battery, or if it could just be the time it takes for the battery to discharge any power remaining in the battery before it starts recharging?

I will update again once 36 hours has passed with the brand new battery installed and everything connected. If I get a green flashing light on the junction box (again indicating a significant drain to 50% charge or less) with this new battery too, then I will know the original battery is not faulty. Then I will do as Duck! has suggested and test the front derailleur.

If that doesn't solve it then I'll be at wits end....