I've had this model before. They're nice. $77 per unit is a very good deal.
And you will need a charge controller to prevent the overcharging of your batteries. This one here will handle ten panels, for a maximum of 10 amps of charge current:
So, for example, if you had a camp in the woods, I would buy five or six or ten panels and a charge controller. And I would buy three or so marine deep-cycle batteries and wire them up in parallel. (Ask a technically minded friend if you don't know what that means. You essentially are using multiple 12-volt batteries to make one large-capacity 12-volt battery. And the charging and the draining of the batteries occurs evenly across all batteries.)
So if you have a camp and if you want to be prepared for the Great American Zombie Wars, get yourself some of these panels.
When you are a terrorist like me, you know how to do these things, because these skills are necessary to doing terrorism properly.