solar panel powered bilge warmer.

Discussion in 'OnBoard Electronics & Controls' started by markstrimaran, Oct 23, 2015.

  1. markstrimaran
    Joined: Dec 2014
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    Location: usa

    markstrimaran Senior Member

    Hi.
    I am curious if a 45 watt solar panel would power a 50 watt 120 volt heated blanket. Thanks
     
  2. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    No. You'd need something like 200w of panels, a 20 amp controller, a size 24 deepcycle battery, and a small inverter.
     
  3. Oleboynow

    Oleboynow Previous Member

    It may very well pay to buy a box of candles and some matches
    you would be better off with a wind turbine and as Phil says , the biggest bank batts you can either A afford, or B your boat can accommodate
    either, 2 volt or 6 volt, in series
     
  4. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    A heated blanket normally switches off, as soon the temperature is reached. 2) My experience is that after 1 hour it get switched off by the person to a lower level, 1/3 - 1/2 normally. 3) If you have 30 watt for 6 hours sunshine 4) radiation for the latest high efficiency 20% panel, you may just make it, if you have a square wave 88% efficiency 80 watt inverter, a deep cycling AMG batteries giving you 70 Ah and 7 hours of sleep. But you may get cold feet in the morning if you are unlucky and the weather is lousy.
    Bert
     
  5. markstrimaran
    Joined: Dec 2014
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    Location: usa

    markstrimaran Senior Member

    bilge heater

    Thanks for the replys.
    I am considering. Disassembling a 50 watt heating pad and putting the heating wire into a 3/4" poly pipe. Sealed water tight. It will be 5' long and so far on 120 volts it tested with out melting last night.
    The purpose is to keep the bilge drain from freezing solid, and to keep the frost action from splitting the hull. Inside a 8" thick polyurethane foam core. This is a boat I foam cored, one off Boston Whaler. Type construction.
    Along the keel is a 1" pcv pipe, that is a inner core drain. It is the white thing in the picture. The bilge drain plug sits up a 1/2" too high to effectively drain all the water out of the boat.

    I am thinking that the 8 inches of foam would hold enough heat to go a few days if unpowered.
    The boat will be tarped and should stay dry.

    I can power it with 120 a/c. I just have an 45 watt solar panel in the garage. I guess I can try it.
     

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  6. W9GFO
    Joined: Dec 2014
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    Location: Olalla, WA

    W9GFO Senior Member

    I would not expect the foam to hold heat more than a few hours.

    The nice thing about turning electricity into heat is that it is 100% efficient.

    If you use a 110V heating element and inverter then you are losing heat via the inverter losses. If the inverter is down in the bilge however, then you still get the benefit of the heat.

    You could also wire up a dedicated circuit to the solar panel. Some power resistors or resistance wire would be all you need. All the energy the panel produced would create heat in the resistors/wire. You would only need to be sure that they are sized properly so as not to get too hot. The problem I see there is that you probably need the heat the most when the sun isn't shining.

    An easier solution may be to put some RV antifreeze in that bilge pipe for winter storage.
     
  7. leaky
    Joined: Sep 2008
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    Location: nh

    leaky Senior Member

    2nd on filling the bilge with anti-freeze - I do that in all my boats, take 5-10 gallons of the stuff and dump it into ever crevice.. Of course if you do not cover the boat water will eventually find it's way in there, so you should cover it.

    However really if you want to keep things from freezing you want a bilge heater. That's why they make them.

    Jon
     
  8. markstrimaran
    Joined: Dec 2014
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    Location: usa

    markstrimaran Senior Member

    120 volt power cord. solar test sucked

    A cup of anti freeze for redundancy.
    My boats foam core absorbs some water I suspect. Part of the plan to keep it dry is to dewater it during the winter. When the air is very cold and dry. A warm moisture area will quickly evaporate.
    I live in Iowa so below zero winter temperatures will be here soon. I think the freezing of water saturated foam will destroy it and possibly split the fiberglass.
    The 45 watt pv solar has enough power to light up a 1157 brake light bulb at around 35 watts. I have two plastic tubes one with the heating wire and one empty.
    I put the empty one I the sun. It heated up too 90 degrees F. On a 60 degree day.
    The solar powered one hit 70. In the shade. With full sun on the panel. So I will use an extension cord.
     
  9. leaky
    Joined: Sep 2008
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    Location: nh

    leaky Senior Member

    There are a lot of whalers up my end (NH/MA/ME coast), like hundreds of them in an average decent sized port anyway... It gets nearly as cold (not quite but it's normal to have a week where you wake up every day to single digits or sub zero)..

    Never heard of it really being a problem freezing, rather the issue is with the weight of the water eventually being noticeable in the boat. You may want to checkout a forum on whalers, there are groups specifically talking about them and probably how to get the water out..

    Kinda a dumb idea packing all that foam into wet places that you can't reach, huh? Seen a whaler sitting on it's mooring ball upside down before, which is basically what happens to any small production boat when you try to sink it, they float but in some non-functional manner where they are still totaled. Better off having a life raft and EPIRB instead of the foam if you ask me, let the stupid boat sink to the bottom and you can float in a thing that you can't fall out of, with help on the way :).

    Jon
     

  10. markstrimaran
    Joined: Dec 2014
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    Location: usa

    markstrimaran Senior Member

    solar powered bilge warmer

    Yes it is a stupid idea. I prefer hollow bulkheads. I read a bunch of Boston whaler forum's about using vacuum pumps too dewater. Prior too building it. Which is why I have a drain pipe and a polystyrene layer next to the hull.
    Most whalers are water tight. The one that I have seen with soaked foam are junk priced.
    I used foam too make the boat very rigid. It was a carbon fiber vs foam core price on a 15' $100.00 hull built in 1959.
    It's trimaran sailboat prototype that if it ever did end upside down. I would just swim 1/2 mile to shore.
    It is also nice to have a self bailing flat level floor to sleep on when camping. I also routinely go out into wind wave conditions that would capsize most 20' fishing boats.
    I will just plug it into extension cord. As the solar panel is not powerful enouph.
     

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