My father in law bought 2 flourescent coleman lanterns model 5348-700 shown here http://flashlightsunlimited.com/relanterncamp.htm. They have been since discontinued. They never really served his purpose though. He bought them for when the power goes out. They have a 6volt 4Ah lead acid battery. They would never be charged when he needed them and now thae battery won't take a charge. I'm sure in the past he probably charged them for a week or so the day after a power outage then put them away till the next outage which by then the battery had drained to the point they were useless. I would like to replace the battery with probably a lithium (maybe AA?). Any suggestions on battery replacements. It doesn't have to be rechargeable since the rarely get any use. I want a long shelf life. I would consider a rechargeable but am concerned about the hazards of overcharging a lithium. They may not be pulled off the charger until I visit again. So it needs to be very low maintenance. I'm not sure 4 Ultimate lithiums would provide enough umph for long enough to make it worthwhile or maybe I can wire 2 sets of 4 in parallel?