"Maintenance Free" is a misnomer. Even if it doesn't have screw caps for the cells, there is a pop-off cover that opens three cells at a time. You need to pop these off and check the fluid level as HKreck stated, and top off the fluid with DISTILLED water. If you cannot leave the coach plugged in or on charge, it's best to remove them. The Chassis battery in the Solera is indeed maintenance free - it's an AGM battery, and the cells are sealed.
Ed (N4RWU) & Becky Taylor
Mistie (Walks 4-down)