Possible battery issues....need help

[Jorme]

I have always run 2 12v batteries in my trailers......Well after my batteries went completely dead after a couple of months sitting last year, I decided to put 2 6v batteries in because of all of the dry camping we have been doing. Well, here is my issue. When I put them in, brand new, my battery gauge in the trailer read 2/3 and as soon as I would turn a light on, would drop to E. So I charged them up to where the meter read full. Turned on a light and it dropped to 1/3. I unplugged the charger last week after a full charge and didnt plug the trailer in to shore power. Yesterday batteries read E. So I plugged the trailer in and went out tonight with the trailer plugged in and the meter still reads E.

Is it the 6v batteries acting up, or is something else going on??