It will depend on what you want to do and the type of regulator you have. Generally to optimize, panel of 24, charge battery of 24 or 2 batteries in series of 12. Each panel of that type at best will provide you with 11A and at least you need 15A for each battery if a slow charge we talk about more than 10 hours for a total charge, I would put the panels in parallel and the input of the regulator and put together 3 series of two batteries in parallel having a 24Vdc line at the output