[snakeyes146]

I'm installing a second battery in a Playbuoy Marquis with a Yamaha 100 outboard and just wanted to know if the ignition circuit (at the switch) gets transfered to the "start" battery, or remains on the "house" battery. The installation of the "start" battery only has the lead to the starter attached and the battery charging lead from the isolator (all on the positive side)

[Big Keepers]

Isn't the ignition circuit a part of the main wiring harness from the controls to the motor? If so, and I hope it is, yeah you'll just run the positive lead from the start battery to the starter. You'll need some wire to connect the two batteries together on the negative terminals. I'd buy the Blue Sea add a battery package and use the auto charging relay to charge the house. It comes with the switch, the acr and the instructions to install. It is real easy. The relay is better than a battery isolator because there is no voltage loss in the relay. When it detects a charging current it closes and charges both batteries.

[snakeyes146]

Thank you very much for the earlier reply, I really appreciate it. I have the second battery installed and have run a separate ground lead to the engine, adjacent to the other ground lead from the original battery. I like the install idea that you mentioned, however, the guy who owns the boat has already purchased the materials, including a solid state battery isolator, that he wants installed and has hired me to complete the job. So here is where I'm at: I have reterminated the alternator lead to the isolator and have made the appropriate connections from the isolator to the positive terminals on the batteries. Now, on the "start" battery, I have only one positive lead running to the starter, however the solenoid control is still on the "house" battery circuit. My question is whether or not that particular wiring at the ignition switch has to be relocated to draw power from the "start" battery, or is it going to be ok to leave it on the "house" battery circuit. What is considered the "normal" install technique?? It doesn't seem wise to have seperate power source for starting, when the control is from the source that could potentially be drained??

[Big Keepers]

If I understand you correctly I'd say leave the solenoid hooked up the way it is. As long as the positive from the starting battery is what the starter motor is drawing off it shouldn't matter how you send 12 volts to the solenoid. All you do when you turn the key is send 12 volts to the solenoid to trigger it to close. When it closes it makes the connection between the heavy wire from the starting battery to the heavy lead between solenoid and starter motor. Normally the small 14 gauge wire that powers the solenoid comes from somewhere in the engine's wiring harness.

Because he is using an isolator make him aware that there will be a voltage loss by the time the charging current gets to the batteries from the alternator. He needs to keep an eye on both batteries to make sure they get charged enough. If he starts to have batteries drain down then they aren't being charged sufficiently by the alternator. If he trailers the boat then it is easy enough to just hook up a battery tender to the batteries. If he is on a mooring or docked where there is no shore power for an onboard charger he could have issues. Something for him to be aware of.