Sram Etap Shifter unusual battery low indication

[Mirco]

We are using the Sram Etap HRD now for about 1,5 years on our road bikes.
After 1 year we had the first battery low problem on the left shifter during a ride. The battery were changed and everything works fine again.
From that point the bike was used for about 2 month until the winter CX Season started and was not riden for about 4 month. So after 6 month I checked the bike and battery status again and again the left shifter battery was at low indication, no shifting possible.
Ok, the battery was changed again and everythings was ok. Yesterday, the same problem again, just before a ride, the Garmin Edge showed left shifter battery at low. What the f...., just 4 week ago the battery was exchanged and now at low again? To perform the ride, again the battery was exchanged, but this behaviour seems to be not normal.

All the other shifter batteries are still at „green“ status, even after 1,5 years of use and also the shifter status of our 3 CX bikes are still „green“ after the same period.

Does anybody have the same problem or an solution? First of all I did a complete new pairing of the components yesterday, but I thing that would not solve the problem.

regards

Mirco

[beanbiken]

Not all button batteries are created equal. Not sure what the difference is but I have had similar experience with other electronic devices that needed new batteries. Make sure you clean the contact areas of the battery before installation as well.

[Nefarious86]

I'd hazard a guess there will be signs of water ingress and corrosion somewhere causing a voltage drain.

[Mirco]

I'd hazard a guess there will be signs of water ingress and corrosion somewhere causing a voltage drain.

Maybe, but we are talking about a road bike, which we normaly use in dry conditions and compared to our 4 CX Bikes, all with Etap HRD, used in muddy conditions including races, where Kärcher Cleaning Equipment is used, I think corrosion is not realy the problem.

[Mirco]

Not all button batteries are created equal. Not sure what the difference is but I have had similar experience with other electronic devices that needed new batteries. Make sure you clean the contact areas of the battery before installation as well.

Yes, that was also my thought, but I am running now the fourth battery and we have 6 Bike with Etap HRD, so 12 STIs and 11 STIs are running on the first battery.

[Mirco]

So, I just did some measurements concerning voltage. A new CR 2032 Cell has 3,25 V. The new Cell yesterday exchanged on the left shifter showed after 24h 2,92 V. The Cell, which was exchanged yesterday showed 2,84 V. So the threshold is at around 2,84-2,86 V were the shifter led shows red and also the garmin edge says „shifter battery l/r low.

I also did the check with the original 1,5 year old battery of the right shifter. This battery showed 3,02 V which is obviously a normal behavior.

[Jugi]

I once heard at a jewellery store, that coin cell batteries may discharge considerably when installed as the contacts easily short circuit during skin contact. I didn’t believe it completely then (sounded like marketing speech to let a professional change a battery) but I guess limiting skin contact while installing a battery is good to keep in mind.

[WilierDood]

It's not the voltage that's important when determining how long a battery will last- it's the rated amp-hour, or in this case, miliamp hours (capacity). As a previous poster pointed out- not all batteries are created equal. Typical lead-acid batteries discharge in a very non-linear way, loosing amperage the lower the voltage becomes. Lithium-ion batteries discharge in a much more linear fashion, often providing full power, or nearly full power until it's completely discharged. My advice- pay attention to the MAH rating of the battery you're buying (search for the highest you can find), and if at all possible, make sure it's a lithium-ion battery- they don't necessarily last longer, but they offer a much more consistent rate of discharge, particularly toward the end of it's life. If the shifters are at all voltage-sensitive, then a lipo battery will perform better in the long run. If you're still having issues with fast drain, even with a lipo, it's probably not a battery issue.

[Mirco]

It's not the voltage that's important when determining how long a battery will last- it's the rated amp-hour, or in this case, miliamp hours (capacity). As a previous poster pointed out- not all batteries are created equal. Typical lead-acid batteries discharge in a very non-linear way, loosing amperage the lower the voltage becomes. Lithium-ion batteries discharge in a much more linear fashion, often providing full power, or nearly full power until it's completely discharged. My advice- pay attention to the MAH rating of the battery you're buying (search for the highest you can find), and if at all possible, make sure it's a lithium-ion battery- they don't necessarily last longer, but they offer a much more consistent rate of discharge, particularly toward the end of it's life. If the shifters are at all voltage-sensitive, then a lipo battery will perform better in the long run. If you're still having issues with fast drain, even with a lipo, it's probably not a battery issue.

Maybe you should inform yourself what kind of battery Sram uses for the Etap shifters. I know that capacity of a battery or accu is responsible in terms of how long may I use a battery or accu until I get a message about the low status. I did model flying for about 14 years. But at a certain point also the voltage drops and this is the case concerning the problem with my Etap Shifter.

[WilierDood]

etap shifters use 2032 batteries, just like a million other small electronic devices. Sram uses whatever battery they get the best deal on that meets their specifications. Why so defensive, mate? Just trying to help

It sounds to me like this has nothing to do with the battery anyway, and perhaps that particular shifter has excessive resistance somewhere in the circuit causing it to be overly voltage-sensitive? I've seen that happen with RC servo's and BEC's, and it happens quite frequently in modern control systems in cars as well. Since the shifter is monitoring battery health, perhaps that circuit is causing a very small parasitic drain? Is the shifter still under warranty?

Maybe you should inform yourself what kind of battery Sram uses for the Etap shifters. I know that capacity of a battery or accu is responsible in terms of how long may I use a battery or accu until I get a message about the low status. I did model flying for about 14 years. But at a certain point also the voltage drops and this is the case concerning the problem with my Etap Shifter.

[Mirco]

etap shifters use 2032 batteries, just like a million other small electronic devices. Sram uses whatever battery they get the best deal on that meets their specifications. Why so defensive, mate? Just trying to help

It sounds to me like this has nothing to do with the battery anyway, and perhaps that particular shifter has excessive resistance somewhere in the circuit causing it to be overly voltage-sensitive? I've seen that happen with RC servo's and BEC's, and it happens quite frequently in modern control systems in cars as well. Since the shifter is monitoring battery health, perhaps that circuit is causing a very small parasitic drain? Is the shifter still under warranty?

Maybe you should inform yourself what kind of battery Sram uses for the Etap shifters. I know that capacity of a battery or accu is responsible in terms of how long may I use a battery or accu until I get a message about the low status. I did model flying for about 14 years. But at a certain point also the voltage drops and this is the case concerning the problem with my Etap Shifter.

That might be the case. As I said, the shifter uses now the fourth battery within 13 mounth comparing the 11 other Etap HDR shifter we use, still on the first battery. Anyway I already ordered a new one, it was delivered 2 days ago, and is installed. Just need to be bleeded again. The old shifter is still under warranty and will be send to the dealer today. When I get it back, I have a nice sparepart or will use it for the next bike of my wife.