no, I mean the 3rd battery. If you look at phat mats diagram one battery to #1 on port motor. One battery to #1 on syarboard motor, then the third aux battery to #2 on the starboard motor. But if you run #1 on both switches, how does the 3rd battery get charged?

then again, that’s assuming cigarette runs the batteries according to the perko diagram.

Screaming blown BBC who needs a stereo battery.......................I do have a 3 bank on board charger when at rest for all three.

Isolation relay works best to charge a 3rd battery without having to do anything.
I ran my on both or 1 or 2 . never noticed a difference.
You wont know if an alternator went bad running on both but it`ll start better.. till you replace all the old wiring and upgrade to a larger size
.The Flat Deck had a switch to combine both batterries for starting.
God Damn those TITS are huge! Congrats.

it you talking about my picture. It’s directly from the 1994 users manual….
.

You got me, I’m sitting here sipping a drink while taking in all this knowledge and the TITS comment had it come out my nose😂😂 I’m a lucky guy for sure!!

You know, it's funny. I've been a big stereo guy my whole life but now I have tinnitus and can't really listen to loud stereos. Plus, I agree 100%, when we're running, I like to hear the motors, not only for any potential problems but just because I f*ckin' love 1k HP screaming through headers! My kid is always trying to turn the stereo up while we're running and I always reach over and turn it down. It's kind of a thing now. lol But I'm referring to mostly when we're beached or floating and running the stereo while the motors are off for hours at a time. If you're only running switches on #1 position and the 3rd battery (aux / lights / stereo battery) will never get charged.

Totally agree, I gotta hear them motors roar!

I run each battery on "1" and change to "Both" if for some reason one battery is weak. Tank to answer your question, my boat had a factory wired house/stereo battery and it was not connected to any switch. It was connected to a battery isolator and it would charge from either engine when it was running. The isolator acts like a diode only flowing current one direction.

Congrats Dish8999, Good looking TG!

that makes sense! If I'm not mistaken, mine may be set up that way as well now that I think of it.

Hope things are well Jim. Maybe we'll get to catch up in '26 in loto at some point, or in KW in Nov!!

Thank you Jim!! And thanks for the knowledge.