[Jack Houpe]

What type of batteries are they deep cycle lead acid or AGM glass matt batteries? If you charge them up and they hold a charge above 12.4vdc you should be OK but if they drain while just sitting with no load you have a shorted cell and will have to isolate them to find which battery is draining the rest of them. With AGM batteries you can only drain them below 12.2vdc a couple times and they are shot at least in my experience deep cycle lead acid are a little more forgiving.