petemorgan

Hi everyone, apologies if this has been posted previously, I have an issue with the battery on my rear derailleur draining even when the bike is stationery and not in use. Fully charged battery attached to the rear derailleur, bike not used for 10 days and set off for a ride only to discover battery was completely flat. Does anyone have any suggestions of what I can check might be causing the power drain?

sarhog

How stationary is stationary? If the derailleur senses movement (say, bumping into the bike), it “wakes up”, which uses power, though I’d think it wouldn’t be that much.

Fully charge the battery, then remove the battery for 10 days. Is it charged or dead afterwards?

Good luck.

On edit: you should ask a mod to move this to bike mechanics sub forum.

gif4445

Battery drain or just battery gone bad?

Meer

Hi, did you solve this problem? I have the samen issue. It looks like the rear derailleur is draining the battery. After one night or ride is empty​​​​​​.

PowerPete

Also my question did you find a solution?

I have a new bike with Rival 4 weeks old. My rear battery is drained without using bike within a few days of charging each time. Bike is not moved or touched between rides and has the latest firmware installed. I've swapped batteries so I don't think they are the problem. The first week I had bike battery was OK. I think it started happening after updating firmware. I've read that others users are complaining about the rear battery draining without use.

SRAM support have told me to put in a warranty claim.

PowerPete

Did you find a solution? I have a new bike with Rival 4 weeks old. My rear battery is drained without using bike within a few days of charging each time. Bike is not moved or touched between rides and has the latest firmware installed. I've swapped batteries so I don't think they are the problem. The first week I had bike battery was OK. I think it started happening after updating firmware. I've read that others users are complaining about the rear battery draining without use.

SRAM support have told me to put in a warranty claim.

Seattle Forrest

​​​​​​Are you able to downgrade the firmware? If you have to warranty the groupset that could be a headache and I would want to avoid it.

PowerPete

Unfortunately I can't find any instructions on how to rollback to previous firmware.

str8jakett

Joining this thread to see if there have been any solutions. I have a SRAM Force AXS rear derailleur draining batteries after about 5 hours of ride time. I've tried three batteries so far with the same results. The bike sits maybe a day or three at a time in between rides. I rode it about three times back in December after receiving it, then discovered a totally dead battery after a few week long hiatus in January. Replaced that battery and did the firmware update all around. Both new batteries I've tried since have produced about 5 hours of ride time, even though they've shown full charge when leaving the house.

Taco Bell

My rear derailleur battery typically lasts a month of riding, or more. Last week I got to the trail and it was dead. I swapped out my dropper post battery and rode for a couple of hours.
When I got home I charged the original rear derailleur battery and put it on the dropper. I checked the following morning and the rear derailleur battery was dead again. I charged that battery too and reinstalled it to the derailleur, it drained overnight as well.
I contacted my bike shop and they had no idea, just said to bring it in.
Anyone get a better explanation, as to what could cause this sudden change?

varunku

same issue rear derailleur batter starts to drain in a day without using the bike. Anyone found a resolution for this yet ?

Bald Paul

Is it possible that your RD hanger is slightly bent? The RD may be trying to "hold" the gear against an improper angle.
I had leaned my bike against my vehicle, and someone else got into the car and caused the bike to roll/fall onto the right side. After that, the RD battery went dead. I found a very light scuff mark on the RD, but the hanger was bent slightly. After I straightened the hanger using the Park hanger alignment tool, everything is back to normal. Just something you may want to check. (p.s.: just because your bike has never fallen doesn't mean the hanger is aligned properly.)

Troul 

You'd think the E Rear derailleurs would be able to "sense" jockey & idler wheel movement to know if it should continue trying to maintain a predetermined position, especially if something gets bumped out of tolerance.
how does the calibration of the derailleur know to keep a position in correlation to gear selection? Are there markings on the cassette that the derailleur senses like a hall effect sensor for a VSS in a transmission?

Bald Paul

I don't know for a fact that the RD senses movement or not. I was just thinking it may have tension on the motor internally and continuously try to get to a neutral position. Then again, I'm still trying to figure out how the derailleurs know the bike is moving, even on a rack on a vehicle. SRAM tells you to remove the batteries if you're transporting your bike on a longer trip to keep them from discharging. It's all smoke and mirrors to me.

unterhausen

Moved here from Electronics.