Gone Outdoors

How to Charge a Battery With a Solar Panel

by Will Charpentier

A solar panel is essentially a battery charger that transforms sunlight into an electrical DC charge. You can keep your boat's battery charged and ready to operate by connecting it to a solar panel. That way, every time you go boating, you're charging the boat's battery as well as your own.

1. Remove the negative output cable from the deep-cycle battery's negative post, using a 5/16-inch open-end wrench. Remove the clamp terminal of the positive output cable from the deep-cycle battery's positive post using a 3/8-inch open-end wrench. Remove any other cables or wires from the battery posts.

2. Calculate the size of the necessary charge controller. For example, if your solar panel provides 100 watts of power, divide 100 by 15. The result, 6.667, is the number of amps your solar panel is providing. Round up to the next whole number, 7, and use a 7-amp charge controller.

3. Plug the charge controller into the solar panel's output socket. Place the ring terminal of the charge controller's red output lead on the positive post of the deep-cycle battery.

4. Set the ring terminal of the black lead of the charge connector on the negative post of the deep-cycle battery. Place the terminal of the red battery cable on the positive post of the battery, and tighten the nut on the terminal using a 3/8-inch open-end wrench.

5. Place the terminal of the black battery cable on the deep-cycle battery's negative post. Tighten the nut with a 5/16-inch open-end wrench.

Items you will need
  • Charge controller
  • 3/8-inch open-end wrench
  • 5/16-inch open-end wrench

Tip

  • The cable from the charge controller should always be the lowest cable on the battery post.

About the Author

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.

Photo Credits

  • Comstock/Comstock/Getty Images