I particularly like 12 volt deep cycle batteries like these: http://www.batteriesinaflash.com/dee...130ah-group-30
The reason is that if a 6 volt battery should fail due to a cracked plate or other internal problem, your camping trip is over.
With 12 volt deep cycles, a minute with a wrench and you are back in business.
Remember when shopping two 12 volt batteries doubles Amp Hours and two 6 volt batteries doubles voltage (but not amp hours).
2 - 130 AH 12 Volt Batteries equals 12 volts at 260AH
2 - 232 AH 6 Volt Batteries equals 12 volts at 232 AH
Be sure to follow the correct wiring when connecting battery banks for even charging and discharging. Many manufacturers get it wrong.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW