Howdy. I've been doing a complete refurbishment on an older 16', which had no battery at all when I bought it. I enjoy being off grid. And while I try to be frugal with energy consumption on principle, a single battery wasn't going to do it for me. I tried to squeeze a bank into an ammo canister to fit on the tongue, but the propane tank crowds that out pretty quickly. So instead I have commandeered the portapotty space under the fore bunk for the purpose. My new, high-amp capable 12v system is self designed. I have three UB12350 sealed lead acid industrial batteries. These are Group U1, but I really didn't care one way or another so long as they fit their boxes. The UB12350 are reputed to be reliable long-term deep-cycle performers; I can concur on this, having put them through their paces under rough conditions. At 35Ah each for 105Ah total, fed by two 100w solar panels, this gives me plenty of power for many applications. The weight is an issue, as with most batteries, but I'm hopeful they are still plenty forward so the tongue can take the strain and prevent any fishtailing. Then again, at ~22lbs each, for ~71lbs total, they don't bend my weight budget TOO much. I was a bit concerned about battery containment, which was why I had preferred to build them into an ammo canister. My solution to that was to put each into its own battery box. I have drilled two ventilation holes, screened these in, and shall keep a very low power computer fan running. Being sealed, I'm not too worried, but "just in case" this puts me at ease. I hope this helps!