Are your 2015 Seneca batteries (engine) maintainence free?
Took the battery cover off under the drivers seat to check the battery water level. I can't even see the tops of the batteries! What a confined space. Can anyone see the brand of batteries you have, and if they are maintainence free?
Engine (chassis) batteries are not on a slide-out tray, there are two wired in parallel under the cab floor accessed by a removable panel inside the driver door area.
I don't have the manufacturer of mine (2014 Seneca 37TS), but they appear to be a typical maintenance free starting battery like you find in millions of cars and trucks as original equipment. They are not deep cycle batteries.
On other Freightliner M2 trucks I have seen in commercial service the chassis batteries are in the same place, but the delivery truck-style functional (but less "pretty") cab steps were able to be removed relatively easily for better access to the batteries.
So I guess we have Jayco to blame, since they install the fiberglass tank cover and cab step assembly that RV owners find "more attractive"!