I have a 1990 BLACK MAX 150. I just bought boat and crank battery died. It wad ac delco m24mf if I remember correctly. I bought a magna power m24m marine. The battery lasted a few days and would not crank boat. So I switched to my backup batyery another ac delco. I staryed watching my vokts on myy fishfinder. I maintained 11.8 volts at wot or ideling. It dropped to 9.5 when I was trimming and while I trimmed the lights dimmed. New battrry I just bought wouldnt turn boat over. It was 2 dead. When I got home I put charger on old acdelco. After 3hours it wouldnt get over 11.8 unless charger was on. Does this sound like baattery issues or more like rctifier or statorr? Just weird that brand new battery lasted 2days before dieing out. I think it has aalot less cca the acdelco. But it never got over 11.8 v. Is this normal or what could it be?
