Traveling by car with SRAM eTap

This is my first season traveling with Sram AXS on my gravel bike and I’ve heard the batteries can drain on car trips.

Is it safe to leave charged batteries on for a 1 hr drive? How about 3hrs? Should I remove them totally when traveling?


Should be fine if the batteries have a decent charge in them to start.

For important events or longer trips I usually take them out just to be safe.


I leave mine in for any local trips but remove before 3 hours or more driving. They activate via movement. I like to put a fresh charge in before anything important and install when I arrive at the event.


@FrankTuna I’ve left mine on for a 6 hour drive to a race, raced and then drove 6 hours home and they still flashed green back home. Not saying do this but, just one story to chew on. I assume they were fully charged prior to the trip but can’t recall for sure. Usually, I take them off and install the batt covers for anything that requires traveling out of town.

1 Like

I would remove them. It take 2 seconds to remove and put in the inserts. Better safe than sorry.


Maybe I don’t understand the question: why would the standby battery consumption in a car be any different than at home on the trainer or in the bike shed? I have never pulled the battery from my rear derailleur.

However, it is still a good idea to take the charger with you just in case.

Because eTap wakes up its electronics based of motion of the bike. So, if the bike is bouncing around on the car (or on a plane) the electronics will stay awake the whole time and use battery charge.


Still, I don’t quite get it: even my drivetrain it wakes up while driving, why would I care? If you rode your bike for the same amount of time, would you worry about the battery? Especially since the derailleurs don’t shift, I can’t imagine they are using much power to begin with.

(It goes without saying that before a trip, I’d charge the battery just to be on the safe side, so I’m assuming you are starting with a full battery. Alternatively, I’d keep a spare eTap battery in my saddle bag.)

1 Like

I don’t think sram has done a good job explaining. I always assumed the talk was about the FD/RD batteries draining. I now think it’s more about the cr2032’s in the shifters that is the worry. i don’t know the logic/sciennce behind accelerometers, bluetooth and the derailleur and shift batteries though…

The batteries in the shifter last for ages. I ride quite a lot and I have to replace them about 1.5 times per year. I wouldn’t be worried about them running out. I always do have two CR2032s in my saddle bag, though. (I have lots of equipment that chews threw them at various rates, e. g. my heart rate strap, my Quarq power meter and the speed sensor. Plus, shifter batteries tend to run out in pairs, so I always have two of them with me.)


Unless you can’t find the inserts :rofl:

@djwalker1260 That’s what I’ve heard and figured better safe than sorry. Thanks!

@OreoCookie I’ve run across this advice (removing the batteries) in a few spots online. You make some good points though. Not sure how much of an issue this is, especially if you stay on top of charging the batteries. Luckily my van has multiple usb charging ports just in case too…I was able to top off my spare battery on the way to my ride yesterday.

Thanks everyone!

Don’t worry. I have had coin cell batteries run out on my during rides, and only because I ignored the low battery warnings. I wanted to eek out a little more life out of the batteries. I’ve learnt that this isn’t worth the hassle. Replacing the batteries takes about 1 minute and a coin.


This is another good reminder to carry them with me! Thanks!!

I get a low battery warning on my Wahoo head unit, and then I change the battery immediately when outdoors or directly after the workout when I am indoors. But they last a long time. I only wished I got a low battery warning earlier. (I have had the same problem with other devices that take CR2032 coin cell batteries, though.) Coin cell batteries are super small and store very well.

If you have a 2x setup, you have another line of defense if you are worried about the big rechargeable batteries: you could swap them between front and rear derailleurs. I am running 1x. I am always on the fence about getting a spare battery, but haven’t needed it.

1 Like

1x but with an AXS dropper…so still have the option to swap if needed!

1 Like

Agree. Just trying to figure out which batteries supposedly drain when the bike is in motion. Derailleurs, cr2032’s, both? Why does taking the derailleur batteries off stop drainage in each situation? Not asking you per se just a general q for any engineer.


It is the derailleur batteries. Motion prevents the derailleur from going to sleep and when it is awake it is checking for a shift signal from the levers. Thus it uses some battery — not as much as when shifting (the motor is not moving) but some.



1 Like

I take mine off for long road trips (it honestly takes maybe 10 seconds to remove the battery and put the insert in), but not if I’m driving to a ride locally. Same for my power pedals (they take maybe 60 seconds to unscrew and put in a ziplock bag). I also check the battery levels on my bike and my pedals whenever I do the chain.


I don’t bother removing it. It’s not like the battery dies that quick. I keep the battery level on my head unit so it’s easy to tell if it’s getting close to dying.

A drive across the country and back wouldn’t kill the battery.

Sure it’s easy to take off but that makes it easier to leave it behind. I’d rather have a battery with me at 10% than one that is at home on my workbench.

1 Like