Voltage DROP ?

My Nautique 92 is running fine , but I have a question. Ever since I've had the boat when I turn on the HEATER , the volt meter drops from about 13 volts to 11. When I turn on the Navagation lights (heater still on) the voltage drops low enough to cause my Perfect Pass to restart over and over. When I turn the Heater or Lights off the Perfect Pass gets enough voltage to operate properly.

Is it possible that my alternator is not charging enough ?

Thanks

I had a similar problem with my 89 Nautique. In my case it, it was a ground problem caused by 14 year old crimp connections.

You first need to determine if the voltage is really low or if its an error in the gauges. Use an external meter and measure the voltage at the battery while the engine is running and the accessories are on. You should have approximately 14 volts. If you don't, then look for a problem with your alternator, regulator, or associated wiring. If the voltate is good, look for a ground problem with your gauges. You can look at my old post from about a month ago in this form with the topic "Low Voltage"

Hope this helps,
-Mark

Yes , the problem is ground related. I will redo the connections this fall.

Thanks to all