an outside battery tray, that will hold one group27... move the batteries inside and use AGM? it a 4winds Majestic 23... it is my mom's she got it from reserve america.. its been a great coach....
Here was my solution to the single battery tray in our Four Winds. There should be room, but it is tight. As you can see in the original post, I made mine with a slide out arrangement so it makes it easy to check the levels, etc.