250 XS Problem

[bep078]

I have a 2010 Mercury 250 XS with around 80 hrs. After a full day of intense driving in rough offshore conditions, I observed the Voltage going down the more time passes by, until in went under 11.4V which activates the Smartcraft Check Engine warning. In the beginning, The alarm was sounding at 3500 rpm, then i left it in idle and warning went off. However, voltage was still low at 11.6V. Some time passed until i drove slowly to put the boat up and by the end, the alarm was sounding all the time and voltage went down to 11.2V.

What do you think this could be? Alternator gone? Something to do with the Voltage regulator? Batt dead?

Any feedback will be greatly appreciated.

Kind regards.

[johnboy 88 vegas]

Check the batteries with a load tester before doing anything else.