Anybody have any ideas why these batteries have gone from 100% to 20% in only about 10 trainer sessions? The bike only gers use on the trainer.
My cadence sensor has been reporting that it’s below 30% charge since I got it (and replaced the battery). 
Is it the TR app which shows the battery levels?
Yes…I wonder if the app is inaccurate?
I do believe it’s a Bluetooth issue.
I’ll slap a brand new battery in my power meter and the TR app will read it at 18% or something like that (the Stages app will read it as 100%).
There’s an old thread about this issue on the forum; search!
Mine shows that its low quite regularly but I tend to just ignore it and it seems fine.
Do you use a Garmin computer at the same time? If so do you switch it OFF or SLEEP? If in SLEEP then sensors can stay connected. Found this with my tickr - shouldn’t but was
No…no garmin computer. I did a search on this forum and I guess its pretty common for TR to read the batteries low even when fully charged or brand new…
Maybe not your specific issue, but I think the Wahoo Cadence sensor that came with my Kickr was faulty in how it are batteries. I suspect something was wrong with it not going properly to sleep in the CR2032 would be dead in a few weeks (even with just a few 1 hour rides). This was a few years back though and they (Wahoo) replaced it for me fairly easily after a brief e-mail back and forth and serial number provided.
If it’s merely reporting a low battery but running ok, maybe not a real issue? My TickrX seems to report low via TR nearly always but I haven’t replaced the battery and it keeps working ok. I think it even goes from low to OK during most workouts (fairly consistently).