Solar Energy

Setting Up Solar Energy on Your Boat

As the prices of gasoline and diesel fuel continue to rise, interest in alternative energy sources such as solar panels is also rising.

Solar panels can provide some or all of the 12 volt energy you use on your boat. Solar panels are espcially useful for those boats that are kept on a mooring or for cruisers who spend extended periods of time away from a dock with shore power.

Deciding on Solar

Some good reasons to get solar panels include:

Avoid excessive wear on your main engine by not running it just to charge your batteries. The cost of running a typical diesel engine is in the $3 to $5 per hour range when fuel and maintenance are factored in.
Offshore safety: Solar panels provide a source of 12v electricity independent of the main engine. If your alternator fails, you'll still have electricity for running lights, radar and autopilot.
Desire to be independent of a dock and save money by staying out of marinas.
Silent, clean power. No need to run a generator or lug fuel from the dock out to the boat.

The downside of solar panels includes:

High initial cost for the panels, controller and wiring.
Difficulty of mounting large panels on your boat.
High percentage of cloudy or rainy days in some northern locations makes solar impractical.
Won't run high wattage loads like a water heater or air-conditioner.

Complete energy independence may take four or five large panels and cost several thousand dollars. On the other hand, a medium-sized panel costing a few hundred dollars will keep the house battery bank on a moored boat charged up during the week ready for weekend vacation trips. The important thing is knowing how much electricy you use and when you use it.

Calculating Your Energy Budget

Before you buy solar panels, make up an energy budget. You'll need to know three sets of information: your energy usage profile, your energy storage capacity, and your energy generation profile. The easiest way to do this is to list out the information on an energy budget form that splits the day into twleve two-hour segments. Write down the amount of energy generated and used in each segment. The worksheet will calculate the net gain/loss and add/subrract it to the running total. Click here to download a sample energy budget spreadsheet in Microsoft Excel format.

Links to Outside Resources

	Item	Link to Detail
How-to Articles
	What size solar panel?	Sailnet article
	Article on choosing solar panels	Jackrabbit Marine
	Article on charge controllers for solar panels
	Introduction to solar panels and their use	BOAT/US article Sailnet article
	Table of expected panel output	BlueWater article
Manufacturers of Solar Panels
	Kyocera	Mfg. Site
	Siemens	Mfg. Site
	Shell Solar	Mfg. Site
	BP Solar	Mfg. Site
Misc.
	Mounting kits and ideas	eMarineInc.com
	Controller modules	Morningstar Inc

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