We don’t understand electrical stuff

The trip from St Petersburg to Key West was intended to be our shake down trip. There’s a West Marine in Key West, and a K Mart and plenty of hardware stores to buy anything we’ve forgotten or broken. We’ve used this trip to wrestle with our electrical systems. Day after day, we’ve had the cushions pulled up, the batteries exposed, and the voltmeter out. Mike has little drawings of circuits all over his legal pad. We don’t really understand how our 12 volt system is wired, what all the switches mean, and how it all works. They say that admitting you have a problem is the first step toward solving it.

We observed that the starter battery hasn’t been starting our motor. When we turn our Perco switch to 1 which we think means that we are using our starting battery instead of our house battery banks, the motor doesn’t turn over at all. We’ve been working around that problem by using our house batteries to start the motor, but that’s not a good long term solution. So in Marco Island, we measured the current at the starter battery while turning the key in the ignition, and learned that we don’t have enough CCAs or cold cranking amps to start the engine. So we had to plunk down some money for a new 70 pound battery.

We also found that running the engine isn’t charging our house batteries the way it is supposed to. In fact, after running the motor for hours on end during our Key West crossing, we were depleting the batteries instead of charging them. I spent one night shirt with the motor and generator running at the same time! Yuck! On the positive side, our solar panels work great, and we have figured out how to interpret the single blinking led light on each controller to confirm that each panel is connected correctly and charging at a high current or low current capacity.

We reached out to Jock, Sanitas’ previous owner, and he sent us a wonderful detailed email about the electrical systems. But we still weren’t smart enough to understand it! Finally, after another day of messy chaos in the boat and reading smelly old users guides and manuals, Mike got a win. He deciphered the flood of error codes transmitted by the alternator regulator to find that it thinks our house batteries are 96 degrees Celsius- almost at the boiling point of water. Since they are clearly not that hot (we can put our hands on them and touch them) there must be a faulty temperature sensor someplace in the system. It is telling the alternator not to put out any charge for our own safety. Well we showed that stupid piece of metal! We disconnected the temperature sensor! Ha! From that point on, the alternator charges the batteries at a rate of 43 amps. Yee haw! Mike did a happy dance in the cockpit to celebrate.

Now with a working alternator, new starting battery, and fully functioning solar (plus that little Honda generator) we should have plenty of electricity for our needs. Mostly lights, navigation systems, and of course the iPad I am using right this minute!

One thought on “We don’t understand electrical stuff

  1. Congrats on figuring out your electrical issues. Very difficult to troubleshoot, especially without updated drawings and wiring details. As you know everything is well hidden and sometimes impossible to trace on a boat. Job well done. Im looking forward to reading about your next “opportunity”. – Enjoy


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