I just bought a 1996 SeaRay 215express with merc 5.7LX 250hp.<br /><br />I want to add a second battery and switch. There is no switch now. I understand the wiring but am wondering if I need the switch with or without the AFD (alternator field disconnect) could somebody explain to me what this is and who needs to use it? mfglmg@msn.com
