Onan Generator and Starting Battery


Hello Group

I have a question regarding my 6.5 KW Onan Generator and the voltage reading of my starting battery when the Generator is running. When my generator is off and not running the starting battery voltage reading on my Bluesea system monitor reads 12.8 volts but when I turn the generator on the voltage reading is only 3.5 volts. Also it appears that when I turn the glow plugs on prior to starting the generator the grounding relay is activated and once the generator is started the grounding relay turns off. Does anyone have an idea why my Bluesea monitor is reading low starting battery voltage when the generator is running and how to correct it?

Also should the starting battery negative terminal be connected to the negative terminal of the house batteries? I do not see a link between the two at this time.

Thank you for your help in advance.
Jim, S/V Liebling SM #207
Puerto Vallarta, Mexico


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