Red eTap Battery Issues

I was without my main bike for a few months while it was being repainted. When I removed the components (SRAM Red eTap 11 speed) the battery life indicator showed green (eg charge good; I stored everything with the batteries removed from the derailleurs.

Fast forward to this week:
I built the bike back & the lights on the bike show red (eg needing charge). However, when placed on the charger, they show green.

I’ve previously gone over a year not riding this group & not had this issue. I’m currently letting the batteries sit on the charger for an hour in hopes it’ll alleviate the issue but I’m not sure I’m optimistic.

Any ideas?

Follow-up. Left battery on charger for an hour. Charger showed green. Put back on bike & it’s red.

If you swap batteries front and rear, does the failure follow the battery or the derailleur?

Yep. Both batteries show red on both derailleurs (& exchanged to the other derailleur) but green on charger.

I’m stumped. They literally sat in a box for four months.

They shift but I’m afraid of getting stuck in one gear on a ride.

Do you have a spare battery… my guess would be the batteries are just dead after fully discharging, but it’s kind of weird that both would die after only four months of not being used.

I don’t have a spare.

Both batteries sat on a charger for at least an hour.

I’m just kind of stumped. I submitted the question to SRAM. I’m hoping for a reply Monday. I’ve got a 70ish mile ride tomorrow. Fingers crossed!

Everything worked fine on the ride. The lights still show as red. I did remember I could check the battery status on my head unit, so depending what SRAM says, I suppose I can just keep track of the charge that way.

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How much fidelity is there in the head units display? Is it just good and then bad and you’re or or is there a middle ground? Like my head unit only displays in 10% increments but I know I can get through two hours on even a 10% charge so that’s more than accurate enough. As long as you’ve got some middle ground before it’s almost empty, I’d just trust the head unit… weird that the derailleurs are showing red though, have you checked the app to see if there a firmware update available?

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I’m not sure how much fidelity there is on the head unit. In all the time I’ve owned this group (since 2017) I never checked the battery status this way as the lights always worked. I knew I could generally get about a month/ ~650 miles before seeing a red light.

There’s no app to tweak the original eTap. It’s a “dumb” electronic group in that it is what it is but there’s no customization. I think there might be a dongle for firmware but I can’t remember offhand. I’ll check the box this evening.

By the by, thanks for the replies. I’m trying to talk my way through the process & the feedback has been helpful.

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The original eTap came with a dongle, but I don’t think there ever was a firmware update for that groupset.

FWIW, I depend on alerts from my Garmin 1030 to remind me to charge the batteries. As expected, the rear derailleur battery is always the first that needs recharging. I generally swap the front and rear batteries when a “Critically low” warning pops up on my Garmin screen.

I get at least 100km more out of the swapped batteries. i.e. have never run out of juice before getting home.

As for your initial query about why the lights show red van though the batteries appear to be charged - I await your update on what SRAM says.

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I did get a reply from SRAM this morning.

*Hi Jonathan, thank you for reaching out to SRAM Rider Support. *

I am sorry to hear that you are having trouble with your derailleurs, that sounds very unusual.
The best indicator of battery life is the LED color when the button on the back of the shift paddle or on the actual derailleurs is pressed. Do those show green when pressed?

Andrew R.
SRAM Rider Support

I replied saying the shifter paddle lights were both green. I’ll be curious to see what (if anything) is said tomorrow. It’s sounding like I can just keep rolling. I may buy a new battery to see if that changes anything.

On my Eagle AXS system pushing the shifter button tells the battery level for the coin cell in the shifter. Pushing the button the derailleur itself tells you the derailleur battery level. So, I would push the button on the derailleur to check the battery and not the shifter.


That’s how it is on Red eTap too. I sort of feel like the representative didn’t understand my question, though I’m not sure how I could have been any clearer.

Each button push on each constituent part shows its battery level.

This ^^^ is accurate.

I think their response is poorly worded, the button on the shifter shows shifter battery status, the button on the derailleur shows derailleur battery status.

Sounds to me like the led on the charger does not display the capacity but whether the charger is actually loading (red) or stops loading because the maximum capacity has been reached (green), but the leds on the bike display the remaining capacity.
So loading stops at a lower capacity than with new/perfectly fine batteries.

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My conversation with SRAM ultimately ended up as, “Huh, that’s weird. We’ve never seen that. Try buying a new battery.”

I didn’t expect anything for free considering the group was purchased in 2017. I was however hoping for some insight. I guess I can follow up with them if anyone else ever encounters… whatever is happening.

Thanks all for the input & replies!

@ulrich.albrecht, that sounds logical. I’m just kind of baffled why the system would work differently after four months of non-use (stored properly).

I have 11 speed Red eTap on my travel bike. I had stored it in Maui in early February 2020, planning to bring it home when I returned in March. Of course, that trip was cancelled, as were our 2020-2021 winter trips. I finally picked the bike up from storage on November 11. I just figured the batteries were dead after all that time and plugged them in until the charger light indicated they were ready to go. I’d guess that each battery took at least two hours to charge so I’d suggest that you just leave them on the charger for longer and see if that works.

Could it be superficial corrosion of the Interfaces on the bike? I would guess that batteries, charger and bike were stored in different locations.

→ contact spray?

I had this problem about 6 weeks ago. Process of elimination showed it was the charger that had failed. Green on the charger, Red (or dead) on the bike. I put the battery in a new charger and it charged fine. Red on the bike can still get you quite a long way so they might be nearly discharged and still functional.