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Old 25-04-2011, 05:40   #1
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Solar Energy Estimates

i will be needing solar power on my boat to run the following things:

Chartplotter(multiple hours daily)
Led interior lights and misc. exterior lights
laptop and misc charging(1 hour a day)
stereo (possibly multiple hours a day)
hot water heater
TV (1 or 2 hours a day)

i have no idea the kind of power needed to run these things. im not electrically savvy at all.

i was hoping that with the appropriate batteries, 2-75 watt panels would do the trick? let me know if thats not enough...

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Old 25-04-2011, 05:50   #2
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Re: solar energy estimates!

Can possibly do all you want EXCEPT the hot water heater. That will draw way more power than you could generate if your whole deck was a solar panel.

The other big power user will be the refrigerator.

How many panels you need will depend to a great degree on the efficiency of the refrigerator and then to a lesser degree on the other electronics. A big stereo turned up fairly loud can suck a pretty good bit of juice.

You really need to do an energy audit to figure this out. I assume you have some kind of volt and amp meters on your boat? Maybe before you invest many hundreds in solar panels you should start with a good battery monitoring system (which you would need anyway) and check typical usage for a while. I just bought a Victron 602. Very nice unit and pretty easy to install.

The water is always bluer on the other side of the ocean.

Sometimes it's necessary to state the obvious for the benefit of the oblivious.

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Old 25-04-2011, 06:50   #3
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Re: Solar Energy Estimates

Where you're located has a lot to do with it, too -- Florida sunshine vs. Newfoundland fog, etc.
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Old 25-04-2011, 07:31   #4
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Re: Solar Energy Estimates

I have a friend that does everything except the hot water and TV on 4 55 watt panels in Florida with a single 255 amp/Hr 8D AGM. He's ok unless he gets several days of cloudy weather. I suspect that you are going a bit too small with 2 75 watt units to get what you want, especially if you are a lot further north or in a cloudy area like the PNW. The TV will take a bit more power than you expect.

Hot water is out of the question from the solar panels unless you get one of the new panels that integrates solar thermal and solar voltaic. These panels circulate water through the panel to keep the panel cooler (they get very hot in bright sun) and more efficient. That water (can be an antifreeze mixture) can be used to heat a hot water tank just like one can do tapping the cooling system of the engine. You can also use a sunshower bag to heat water, though I find that they cool off quite rapidly in the evening, which is when I usually want a hot shower.
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Old 25-04-2011, 19:09   #5
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Re: Solar Energy Estimates

to solve your solar hot water heating issues - you can purchase the regular solar hot water heater manufacturer's "demonstrational" units for around $250 you can see it at this link here

If you would like for me to run a complete load analysis for you and your solar needs please send me the energy consumption each of your loads need to run and how often you will run them. Also please clarify whether the load will be AC or DC and will send you a completed worksheet showing what you will need as a minimum and maximum.

Also a helpful aspect will be the location you will be using the solar system the most.
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