I've been running my boat out on the raritan bay in NJ for stripers and had a problem last week... my batteries were dead and wouldn't even come close to kickin the motor over. It was cold morning and one battery was having trouble (I figured it was low) so I switched the perco to "ALL" and started the motor... I ran out to the fishing grouds that way too. I started it one more time to set a second anchor and had my GPS and VHF running all day... and forgot to switch the perco back to "1" or "2". When I tried to start the motor a few hours later, dead. I immediatly thought the motor wasn't charging the batteries... but I don't think so anymore. To make a long story as short as possible... I got the boat home and found out one battery wouldn't hold a charge, so I replaced it... the other battery was fine,so I charged it. My buddy told me he would help me swap out the parts that needed replacing on the motor... but being hard headed I wanted to fish in the meantime so I put my small tiller motor on the boat so I could atleast limp home if it happened again. But low and behold, the motor and batteries are fine... and I've been out twice... yesterday I started the boat five times, ran for a total of 30 miles, had my gps, sonar, and vhf running all day and the battery is still charged... and I never even took the perco off of "1". So I'm pretty sure it's not the charging system. (So much for a short story huh) So this is my question... what the heck would cause my batteries to just die like that? I've heard that a dead battery in series will kill the other batteries in the series, just suck the charge right out of them... but the batteries should be in parallel on a perko and wouldn't effect each other... any thoughts?