I just boat an older fish and ski boat with a 150 black Maxx 1990.. The cranking battery died on me so I took it to have it checked. It was a ac dekco cm24mf I believe thats cirrect modell number. The guy sold me a magna power marine battery 24m4.. I took boat out and after a few starts the battery died out.. so I switched to my backup ac delco battery. It cranked fine. I noticed on my depth finder that I was only running 11.8v while running wot. Whenever I trmmed I noticed it droped down to 9.5v. And went back to 11.8. It restarted fine for rest of the day. Sometimes if I was tilting motor and running slow it would be 11.3v but as soon as I throttled up it would go back to 11.8 but no highrr. In other words. Im wondering what is going on, my new battery just died out. I noticed its got less cca then the acdelco but im worriedbmy boat isnt charging battery.. I heard you suppose to have 13-14v while wot.. how dobi check and what dobi check. What about my new magna power battery? Is it still good?
Thanks