Electrical Diagrams


Low Quality Overview of All Diagrams


  1. Electrical Storage:
    1. Batteries: 5 x AGM 105 Ah Batteries. West Marine 8A31DTM 15020258 new on 2014 JUN 30. one dedicated Engine Battery, two House 1 batteries and two House 2 batteries.
  2. Charging Sources:
    1. Alternator: ? (Haven’t looked!) with Balmar ARS-4 Regulator.
    2. Solar: 2 x 100 W Renogy panels with Intelligen 30A PWM Solar Controller.
    3. Wind Generator: 400 W (Removed after throwing a blade into my friend’s inner thigh).
    4. Shore power
  3. Electrical Draw:
    1. Inverter: Freedom F20 outputs to AC Outlets (almost never used)
    2. DC items: Fridge, lights, water-maker, radios, GPS, Phone Charger, Laptop, etc.
  4. Misc Items:
    1. Battery Monitor: Heart Interface Link 2000
    2. Battery Integrator: Newmar BI-100 (Connects at 13.2V, disconnects at 12.8V)
    3. Automatic Charging Relay: Blue Sea L-ACR 9012 (Connects at 13.6V, disconnects at 12.6V)

My boat came with a complicated electrical system and no diagrams. So every time electrical gremlins appear (corroded wire, connection vibrating loose, etc) I make notes and scratch out a quick diagram so I never have to trace the same electrical wiring twice. Crawling around in tiny spaces with the hot sun beating down while trying to find which wire has corroded through is no fun! Eventually, I’ve built up a pretty good set of diagrams so I can simply reference which wires power the device that failed. I disconnect both ends of the wire, test for continuity with my multi-meter, and re-run with a new wire. These diagrams are worth their weight in gold, saving hundreds of uncomfortable hours.

I use a simple, free computer program called TinyCad (http://sourceforge.net/projects/tinycad/) to create the schematics. Each schematic is laid out so if I hold it up to the actual area on the boat everything matches up visually. For instance, the BATBAR schematic lays out the electrical components on paper as they are seen in the battery compartment on the boat. The battery isolator is on the right, the 5 batteries down below, and the wires follow similar paths. I find this makes finding things much easier while actually working on the boat.

I split the electrical system into 7 pages, each page an area on the boat: BATBAR (Battery Compartment), BILGE, BUSBAR (The bus bars located behind the companionway), CB (Circuit Breaker panel), COMPPANEL (Companionway Panel found on the reverse side of the circuit breaker panel), ENGINE (The terminals just above the engine), and MAST/VBERTH (The terminals located next to the mast and in a v-berth cupboard). I then separated each area within a page and assigned letters. So one end of a wire may be located at BUSBAR-CL4 (BUSBAR page, area C, Left side, number 4) and I can immediately see the other end of the wire is located at CB-V10 (CB page, area V, number 10). I can now trace these wires in a $1000 suit and never get dirty.

I know each boat is very different, but I’m posting my diagrams here for reference. With a bit of study, you can see how my two banks of house batteries and one engine battery are isolated when discharging (preventing cross-flow) and automatically connected when charging. You can see how they can be charged by the engine’s alternator, wind power (currently disconnected as of 2014), solar power, or shore power. You can see how my inverter is wired up for 110V AC outlets and how my Heart Interface is wired for battery and charge monitoring. Everything is set up to extend the life of the batteries as long as possible with absolutely no manual switching by the operator. It’s all automatic.

If you have any questions about electrical options on your own boat, explanations on my setup, or comments on how my system could be better, don’t hesitate to comment.

Here are the .pdf versions:

4 Responses to Electrical Diagrams

  1. Tom says:

    I had raced on a Cal39 named Siren in the 1998 Pacific Cup and was surprised to find another Cal39 named Siren until I realized its the same boat which did explain why your wiring diagrams seemed oddly familiar.

    I did much of the wiring on the boat in preparing for the race, so I’m sorry to see you didn’t get the wiring diagrams with the boat. I don’t know how much has changed over the years, and it sounds like you have reverse engineered most of the wiring, but I still have, on my computer, the documentation: wiring diagrams, tables, labels, etc that I made back then. If you want them, I’d be happy to send you copies.

    • Adam SailorsLifeForMe says:

      Oh wow! That’s awesome! I don’t know much of Siren’s history, and it would be great to hear some stories from her past. Those electric system files would also be great to check out if we could get in email contact. How did you find this page?? It’s really hidden in the Guide Search results :) Feel free to send me a message from the About The Author page and I’ll reply to that. Thanks Tom!

  2. Dick says:

    What tinycad libraries did you use ?

    • Adam SailorsLifeForMe says:

      I gave up on using libraries and just drew my own. Faster in the long run :) I actually created my own library for the terminals since I reuse those so often.

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