So I'm out at lost lake right now. My volt gauge is reading over 18 volts and the alt is a one wire and is brand new. Boat ran great for a min and then wouldn't start up after floating for a few min. Sounds like the battery is dead but the battery is reading 12 volt and 95% charged. Does anyone have any ideas what could be?

It may be buried in a post on here somewhere, but what do yo have the big post of the alternator wired to?

It sounds like the alternator was running the dash and not going to the battery... The single post alternators use battery volts to regulate and excite.

Just swapped it strait to the battery and still over 18 volts without the motor running.

Wha? 


So help me out here... I have had a few  With my dinner.

The engine off, alternator not turning, simple large terminal to the battery and you are reading 18 volts? Your volt meter is FUBAR... I think...

Something is really wrong. You only have a 12.5 volt potential, so how do you have 50% more? 

Do you have dual batteries?

Sounds like a wiring/gauge problem. Bet it'll be an easy fix with a fresh take on it in the morning.

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