Low voltage

caik01

We were recently out on the water and stopped to swim, shutting off both motors. When we went to leave only the port motor would start. We tried to jump the starboard motor with a jump back and had no success so we called boat us and they tried to jump it and still nothing so we got towed in. We replaced all 4 batteries on the boat and are still getting low volts around 11 when at the dock on shore power. Even our VHF radio alarms low battery with the new batteries. Any ideas why we are getting such low voltage?

skennelly

Sounds a lot like what a bad ground would do.

Also check connections going to the switch, isolator ect...

caik01

a bad ground to what? the alternator?

Ian

You should have a common ground point that comes form your batteries, perhaps it has bad connections. Where’s the 11V - at the battery or off the dash meter?

caik01

dash meter

Ian

Check with a meter on the batteries, measure and record each. If still at 11, disconnect shore power and start up, see if they get to near14V. If so then it sounds like your charger could be a problem and/or the grounding.

caik01

thank you, I will try that