Copied from my last post:
Now, there is really only one electrical challenge left, the engine alternator. For those that don’t know, a diesel engine (which is what I have) only needs power (battery) to turn the motor over to start it. There are no spark plugs like a gas engine as it explodes the fuel to drive the pistons simply by compressing it on one of the up strokes of the piston. So, the alternator in your car has to create electricity by being turned by the running motor to continually provide electrical power but the diesel only needs to charge the battery so it will start next time. Since I have a battery charger when plugged into the shore power at the dock, the alternator has no actual purpose at the moment and isn’t hooked up. It is just sitting there spinning, making electricity that isn’t going anywhere.
Now, if and when we are away from the dock, say off shore cruising, the batteries that start the engine and run the boat generally will need to be charged and running the motor (and hence the alternator) will be required. So that is now my last major electrical challenge but for the time being, being in the slip and having shore power, I am not lacking for battery charging capacity.
Update:
I removed the alternator from the engine and took it to NAPA Auto Parts. They sold me a replacement but there was a plug on the back that they had to order so, while waiting for a couple days, I started (continued) reading up on how to wire it in, I discovered that I had the wrong alternator. What I had was for an automobile not a boat, It was rated at 63 amps @ 6000 RPMs. My engine only does 2500 RPMs at full tilt. So, at the advice of a fellow boat owner 3 slips down from mine, I drove to Livermore to Dean's Auto Electric shop and talked to Dean. What I had was low output at high RPMs and what I needed was High output at low RPMs. So, he is building me an alternator that will put out 140 amps and will kick on at only 400 RPMs. He also sold me an Isolator which will connect both battery banks when the motor is running so both banks will charge BUT will disconnect (isolate) the battery banks when the engine is not running. In that way the engine battery will stay charged for starting the motor next time while using the House battery bank for lights etc.
So, now I only need to hook up the alternator and Isolator next week and I will have the 2 charging systems, AC / Battery Charger powered by Shore power and DC / the running motor when not in the marina (out cruising).
