There is a thread on how to change the battery out with pics, but can't find it right now. If you do a few searches, I am sure you can find it and maybe someone has a link to it
Ed's manual may have some info on it. Below is what I copied from somewhere.
On page 99 it tell how to get the battery out.
The chassis battery is accessed through the passenger side dash on the Axis and
1. Remove the passenger side work station.
2. Remove the seal and wood access.
3. The battery will be below and forward of the opening.
4. Reinstall the wood access panel.
5. Reseal the panel. Failure to properly reseal the panel will allow air intrusion into
the cab of the motorhome.
6. Reinstall the passenger side work station.
2015 Thor Vegas 24.1 in Ocala