Batteries stopped charging

Thanks everyone. We are in a campground. I'll print your replies and give them to him in the morning. I'll take my meter along and try to help him. I'd hate to see him call out an RV tech if it's just a fuse or something simple. I'm not too familiar with fivers as I've never owned one. He said he just had one of the batteries replaced so I'll start there and check each one to see what they're reading, then I'll look for the charger. I have the phone but I also have a scope that I can hook up to the computer. I'll let everyone know what I find out tomorrow. Thanks again....Dennis