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Old 06-23-2013
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Question How do I calculate my power needs?

I am thrilled to say that I have just bought (& now live on) my first liveaboard!!!!

I was just about to start looking for a solar panel kit and then realised I have no idea how much I actually need.

I live in the UK with 'limited' sunshine shall we say, albeit I do not need to power a great deal...

12v coffee maker (once a day 15mins)
iPad mini (1 full charge a day)
2-3hours of light per day (12v fluorescent tubes)
Small 12v Bluetooth speaker 2-3 hours per day
Charge mobile phone 1charge per day

That's about it.

Any input would be greatly appreciated.
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Old 06-23-2013
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Re: How do I calculate my power needs?

It's all about "amp hours" Sailboat Electrics (Don Casey) is a great book for all your questions David!

I am thrilled to say that I have just bought (& now live on) my first liveaboard!!!!

Yay! What did you get? but!
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Old 06-23-2013
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Re: How do I calculate my power needs?

Install an inexpensive battery monitor.
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Re: How do I calculate my power needs?

Quote:
Originally Posted by Seaduction View Post
Install an inexpensive battery monitor.
I have installed 2battery monitors, 1 for each battery.

But they only show the voltage of each battery and I am not sure exactly what level it should show for fully charged and needing a top up???
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Old 06-23-2013
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Re: How do I calculate my power needs?

Hi David,

I dont believe anyone can calculate what a boat needs.
I have read a thousand threads and... basically... they are all wrong. A boat will decide herself how much she is going to use. My boat would spit the dummy at the coffee maker! I have too much sugar in coffee so it will suck the battery dry.

A better idea is to tell us how big your boat is and haw many amp hours are your batteries.

Then we will pontificate and try to work out how much money you have and tell you to spend the LOT on as many solar pannels you can before being chucked in Debtors Jail.

When you have all the solar you can get then you will know if you can add useful things like a beer-maker-colder.

Hope this helps.


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Old 06-23-2013
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Re: How do I calculate my power needs?

I am watching this with interest as I too plan on spending a few weeks to months aboard (depending on the season) and will need to figure out how much solar I need to keep the batteries in topped up shape.
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Old 06-24-2013
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First do a power condumption diet in amp hours of your equipment daily. Then we can talk. Ie lights, reefer, computers, electronics, pumps, etc.
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Re: How do I calculate my power needs?

Download "Battery, Load and generator calculator" by Bill Roosa here: Sailboat Solar Panel News---Information

It will give you something to experiment with.

You can also check your battery voltages after a day and see how the % you have drained the batteries. That will give you another estimate.

Also see the Don Casey Library, "solar panels and calculating demand": Sailboat Solar Panel News---Information
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Old 06-25-2013
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Re: How do I calculate my power needs?

Thank you everybody, away from Internet connection for a while, will check battery sizes and post back in soon...
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Old 06-25-2013
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Re: How do I calculate my power needs?

You would need to calculate how many amps you are drawing on each appliance to figure out what your daily draw is. Generally speaking I would say get the biggest pannels that you afford and will fit on your boat.

However, if you are living aboard in England, I would consider buying a wind generator first. I would think you would have more wind than sun on a daily basis.

Here on Yofy we have both and we currently live aboard in a very sunny part of the world. But when we have constant draw, our wind generator will pump up the batteries at night. And of course its great on cloudy days.

Manny
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