Energy Manager

Discussion in 'OnBoard Electronics & Controls' started by chicodesouza, Oct 7, 2013.

  1. chicodesouza
    Joined: Oct 2013
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    Location: Brasil

    chicodesouza New Member

    I'm new to the forum and want to give my congratulations to everyone!
    Not long ago I bought my first sailboat (32 feet) and I'm redoing all the electrical part.

    I'm trying to figure out the best way to make the management and control of load and consumption of batteries, preventing loss and overcharging.

    The whole electrical system is 12V dc.

    I will have 4 power sources:
    - Engine Alternator: 80A @12V
    - Solar Panel: 46 Watts - 3.8A @12V
    - Wind Generator: 250 Watts at 24.3 knots (12.5 m/s) - 20.8A @12V
    - Land Source: not yet selected (appreciate suggestions)
    I have 3 battery banks
    - Lights and electronics (2 batteries)
    - Refrigerator (2 batteries)
    - Engine start (1 battery)
    I will change all, but probably about 150Ah (maybe 220Ah) each

    I tried use Google Search, but unfortunately did not come to any conclusion. I'm beginner.

    Could someone help me indicating what equipment should I buy to make this control and management and how to connect them?

    Sorry about my poor english. I hope you understood my question
    Thank you in advance
  2. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

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  3. michael pierzga
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    michael pierzga Senior Member

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  4. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    The management will be much easier if you abandon the idea of 3 banks. Just make one large battery bank for everything except the starter and engine basic instruments, they must stay separate so you can start under all circumstances.

    Buy a large capacity solar regulator with an alphanumeric display. It supplies vital info about battery condition and what is happening, prevents overcharge and switches off all non-essential users in case the charge level approaches the minimum threshold.
    Connect the windmill to the controller as if it were a solar panel.

    Also buy a switch mode battery charger to use shore power. The charger must accept anything over 90 volts, AC or DC without flipping switches.
  5. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    traditionally it been prefered to keep delicate electronics off the service bank to avoid voltage spike damage.

    its not a bad idea. there are other ways to protect electronics, but these dc dc power supplies are expensive and consume power
  6. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    For a boat that size, there are three modes of operation.

    1. Your not on the boat and it is taking care of itself.

    2. You are on the boat for a day trip.

    3. You are cruising and must be self sufficient with respect to electrical needs.

    Number three can usually be done in energy miser mode unless you really plan to do extended offshore cruising and you want the autopilot to run the boat through a week of bad weather. I can cruise two people on my 38'er using three Walmart series 24 marine start/deepcycle batts. But I have 250 watts of solar and most of my electronics are of the portable variety. I have two inverters on the boat, a 150W job that runs my laptop and my slow rechargeable battery charger and a spare 300W unit that is fan cooled and almost never used, but will run tools and a fast charger. I can go months without using the motor. I have never run the motor at anchor for charging. I also own a Honda generator which I only used when I was living aboard in the winter, I don't bother carrying it when cruising. I ran it about 20 minutes a day.

    Start small and give yourself options to expand. When you get fed up with the wind genny, Replace it with a pair of decent solar panels. Isolate sensitive electronics such as depth meter, electric compass, and autohelm from diesel start and anchor windless. An ordinary battery switch can do that. Be very conscious of the load draw of appliances if you plan to cruise or live aboard on the hook. My TV = 22W, DVD = 6W, find a laptop that doesn't need 150W to run email. I run a little 8$ fluorescent light off the inverter if I want reading light night. LED nav lights are a boon, but I don't have them yet.

    I'd start out with mostly portable handheld devices and integrate them as desired as time goes by. You can update your phone for nearly nothing once a year. You can't do that with boat electronics. I still run on a $75 handheld GPS with laptop navigation and electronic maps downloaded from NOAA (with paper backups, of course, and I still workup my routes on paper, then go to the laptop.)

    As far as the fridge goes, that's the killer. In a perfect world, a two speed compressor feeding a two gallon plate which runs on high off shore power or solar and only runs on low off batteries if the box temp rises to a temp where it does some good is the best system I've seen. But that is a tall order for a 32' boat and may not be worth it if you spend a lot of time at in a marina. My exgirlfriend would disagree, though. She left me for a guy with a fridge on his boat:D.
  7. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    Yup...refrigeration...mega power

    One thing I appreciate about sailing in Greece is frozen water bottles. Almost every market has a big cooler full of frozen 1.5 litre bottles. They drastically cut my power consumption. A six pack case of them keeps the refer cold for days

  8. jonr
    Joined: Sep 2008
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    Location: Great Lakes

    jonr Senior Member

    > refrigeration...mega power

    It's proportional to how much insulation you have - so vacuum panels may be of interest.

    Trying to stay on track - I'd keep the solar panel controller separate if it is doing MPPT. Perhaps use a diode or automatic switching device to allow the primary bank to charge but not discharge the engine battery. Running batteries down too far/too often ruins them, so an automatic shutoff would be helpful.
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