J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Ignition switch replacement?

hmmm, maybe the Solenoid itself is buggered, but you said that changing the connection did fix the problem. Where are you measuring the voltage drop? At the battery terminals?

If i were you, I wouldn't put my batteries on the charger at all in the summer, or only once and a while if you aren't sailing regularly. Especially if they are new. If you are getting out on the boat, the half hour or hour you might run the engine will charge the batteries sufficiently to maintain.

Additionally, you should always start your engine with the batteries on "both" if you need to charge the house battery too. I don't believe our stock battery selectors are the anti-surge type so it is really hard on the alternator to move the switch when running.