A huge +1 and a 'me too' for Trojan batteries!!!
I bought a J150 Trojan battery in 2006 for my camper. I water it every spring, and I keep it connected to the charger. The camper lives in a heated shop when not being used.
This past weekend I noticed the battery was getting a little soft. It went down a lot more overnight dry camping than it had in the past with a similar load. This is probably due to some inadvertent abuse recently - I left a fan running in the camper and the power cord had come unplugged - and flattened the battery. So I went out yesterday and bought a new Trojan battery.
Evidently the J150 is an unusual model that is tough to find. They sold me a T-1275 which is almost the same size (slightly shorter), and they said it has the same core as the J150. The Internet shows it has the exact same specs, so I suspect that is accurate.
Trojan batteries are tough to find, I had to drive most of the way across the metro area to get one. And at $230, they are not cheap. Doing the math, if it lasts 10 years like the last one, that is only $2 a month. Versus a $100 battery that lasts 36 months, it is significantly cheaper. Trojan batteries are not intended for these applications. The J150 was designed to fit a floor buffer, and just happens to fit the battery box on my Lance camper.
Yeah, if you are keeping your camper for a while, invest in a Trojan battery. Money well spent in my opinion.
-Eric