Yay, today's battery debate, I was getting worried..
To the original poster, please ignore the 50% discharge rate bogus information. If you purchased DEEP CYCLE batteries in 6v format, they are designed for DEEP CYCLE down to perhaps 80% of discharge. If you do this regularly, you will likely not get 8-10 years out of them like some do, but you bought them to give you the amps when you need them, so when they're tapped out, buy new ones!
The 50% rule applies to those on 12V marine batteries which aren't made to deep cycle (even though they often state this on the battery)
good advice on the 3/4 stage charger with desulfation / equalization modes. I personally use the Progressive Dynamics PD4600
happy travels
