IF you plan on any camping off the power grid you really should look into a real "DEEP CYCLE" battery.
When camping off the power the grid you will b e running down your battery to the 50% charge state and then re-charging back up to the 90% charge the next morning. You can just do so many of these cycles before having to do a full 100% charge state otherwise you will start loosing performance of your batteries. this is where true "DEEP CYCLE" batteries are at their best.
You can re-charge your 50% depleted deep cycle battery about ten times before you have to do a full 100% charge. If you are setup for smart mode technology charging then you can re-charge each day in a short three hour generator run time. A full 100% re-charge will take a 11-12 hours generator run time...
Cost is a big factor for most of us and the golf cart 6V batteries are everywhere so this keeps the cost down. You can get a good GC2PLUS 6V Golf cart battery now from CostCo and SAM.s club for around $90. This is equiv to the Trojan T105 6V battery. Costco and Sam's club also has the next level down GC2 6V battery that runs around $70 each. These batteries are close to the same size as your original GP 24 battery just taller. If the MARINE battery has a START CURRENT rating then it is a COMBO type deep cycle battery. The true DEEP CYCLE batteries only lists the AH rating.
If you have the combo batteries probably like the one you have now you really have to watch when discharging them. These kinds of batteries will NOT withstand very many times going below the 12.0VDC levels... You probably already have experienced draining your car battery down overnight for one reason or another. It is never the same after you do that and will have to be replaced pretty soon. The GP24 combo battery is designed to be alittle better at this but not much more better haha... The true "DEEP CYCLE" batteries are designed to be able to drain down and be re-charged back up. That is what the "DEEP CYCLE" in their name referr too.
If I was going to do some camping off the power grid I would go for the two GC2 6V Golf Cart batteries... Two in series makes a large 12VDC 220AH Battery for around $140. Its all about the AH rating (more is better) and how long they will run producing 12VDC @25AMPS (RC rating).
In my simple case with my OFF-ROAD POPUP I can draw 12VDC @20AMPs from 8PM to 11PM and then drop back to 1-2AMPS until 8AM the next morning and my 255AHs battery bank will be discharged down to around 12.0VDC which is a good reference of about 50% battery charge state. Then I re-charge my battery bank back up to 90% charge state in about three hours using smart-mode charging technology using my 2KW Honda generator so that I can do this all over again for the next day/night battery run. We do just about everything we do at an electric site but without air conditioner or high powered microwave. Everything else is fare game... Watch HDTV everynight and light up our corner of the camp ground.
Works very successful for us camping off the power grid.
Roy and Carolyn
I claim Horse Creek Country in Southern Ill - Momabear is from North Texas
We live in King George VA
RETIRED DOD DOAF DON CONTRACTOR Electronics Tech 42YRS
"We're burning daylight" - John Wayne
2008 STARCRAFT 14RT OFF-ROAD POPUP with PD9260C and three 85AH 12VDC batteries
2010 F150 FX4 5.4 GAS with 3.73 gears - Super Cab - Towing Package - 2KW Honda EU2000i Gen
K9PHT (since 1957) 146.52Mhz
"We always have a PLAN B"