Hi all,
A new device handler has been posted only a few hours ago here: https://github.com/SmartThingsCommunity/SmartThingsPublic/pull/2671
It changes the algorithm used to measure the battery remaining percent and it worked for me. I now have a 100% instead of a battery error.
I used these instructions to install the new device handler: FAQ: An Overview of Using Custom Code in SmartThings
You can change it in the IDE without having to remove the device.
Cheers!