How do you fix 6 volt golf cart batteries when the cells are reading bad?

I would not recommend trying to save your old 6V Batteries. Attempting to save old Golf cart batteries can be dangerous. If your old batteries have "swelled" or gotten enlarged where the battery is bulging out, it is time for replacement. There is a chemical solution that can be added to the old batteries to give them some more life, but it will NOT last long. In fact, I would gamble to say that they would probably fail within 3 months. Really not worth the hassle of purchasing the chemical, charging all the batteries only to have them quit on you. I too am looking for 6V Deep cycle batteries and I have found "they ain't cheap!" I would recommend saving your money and purchase a high end golf cart batteries and get the 5-7 years of use out of them. Anything else would be like putting a band-aid on a bullet wound. You can expect to pay anywhere from $90-$225 for each 6V battery, depending on the brand. Trojan Batteries being some of the best out there.