2005 Jayco 5th wheel battery connection

My alzheimers is kicking my butt lately. I stored the camper last fall and pulled the battery out. Today I went out and had a brain fart as to what cable goes to which post. One cable is white and has a loop end with a red collar around the crimped end of the connecter. The other cables are a pair of black colored cables spliced into a green colored fused piece that connects to the battery. Common sense says that green would be ground and normally black cable is ground on a 12 volt system. I also assumed the cable with the red end would be positive. Well that's the way I hooked it and as soon as I touched the cable to the terminal I got sparks and blew the fuse. Anybody with a similar 2005 Jayco 5er with the same set up? Thanks in advance for helping out a brain dead weekend warrior...