Another very good deep cycle battery is an Odyssey. I have a buddy that has 2 of them in his diesel truck that he swears by!! And talk about heavy, wow!! But thats all the extra lead plates that gives its deep cycle abilities. Now this one has to be mounted like a "normal" battery...because it still uses lead plate and liquid acid inside.
Odyssey batts are Absorbed Glass Mat just like Optimas. No liquid inside. The Optimas use spiral plates, the Odyssey uses flat plates.
According to the mfr.(ODYSSEY battery - Design Advantages), flat plates mean more plates/power for a given footprint.
Odyssey can be mounted in any position except inverted.
Isn't Optima garbage these days? Was I misinformed, or maybe they are not that way anymore? Anyways, I just left my 4r outside for a few cold snaps, over a 3 week period without starting it. Replaced w/ an Interstate for $138 and running strong since fwiw.