Probably a silly question - but have you tried a battery reset?Now the other warranty replacement battery e8035 shows 11 cycles and 90% health. (I just received it a little over a month ago.) The other battery is still at 91% health at 7 cycles.
My wife's battery has a e8010 battery and it still shows 100% health at 9 cycles. It is almost 5 months old.
I think something is wrong with Shimano's e8035 batteries.
Probably a silly question - but have you tried a battery reset?
1) # of charging cycles 17
2) remaining capacity 100%
3) I use E6000 charger exclusively
4) Battery BT-E8010 504wh
6) 12 months old / ~ 900 miles
I store the battery between 15-20 degrees celcius in a dark chamber and try to only charge it to 100% when I need it and then only right before I leave for the ride. I also try to avoid to fully empty it if it's not needed and if it happens I charge it up as fast as possible.
When I store it longterm then at 30-40%. I ride almost exclusively in Eco/High mode with 90-100 rpm and Im fairly light (around 70kg with gear). Boost-mode feels to strong anyway with that weight.
It seems that there is something wrong with BT-E8035 batteries. So far I've had 2 of these batteries and both have dropped capacity exactly the same way: 100%>90% at 10 cycles and 90%>87% at 20 cycles. Currently I'm at 24 cycles so let's see what happens at 30 cycles... On my previous bike I had 2 BT-E8010 batteries and one was at 92% after 80 cycles and the other at 100% after 20 cycles. I've handled all of these batteries exactly the same way: usually I ride until the bike shuts down and then use the fast charger to charge it to 100% after the battery has cooled/warmed to room temperature. I don't store it at 100% for a long time because usually I ride almost every day.