Solar Power Part 5- Charge Controller and Marine Battery

 I have been working on my solar power bank system for over three years. I have a solar panel in front of my window, connected to some 12-volt batteries. I mostly used old sealed lead-acid batteries with a couple of new ones. Unfortunately, I didn't add a charge controller. I thought the system would be fine without it. However, when I was away for a few months, the solar panel continued to charge the batteries every single day but there was no load drawing power. Unfortunately, it is bad for this type of battery to keep overcharging it (although not nearly as bad as overcharging lithium batteries). Other times, the batteries got over-discharged, which is also bad.

After four years, some of the old batteries were barely putting out any current. I decided to get a new battery, and add a charge controller this time. The new battery is a marine battery I got from a neighbor. It's not brand new, but it definitely works well. It is designed to start a boat engine, not for off-grid energy storage.

I made a battery terminal from copper tubing so that it could be crimped onto the end of a wire. I cut a short length with a hacksaw and then split part of it open with a utility knife. Wow, copper is soft! After I attached the wires, I covered up the positive terminal to ensure nothing could accidentally short out the battery.  

The charge controller will ensure the battery doesn't get overcharged or over-discharged in the future, even when I'm gone for a few months. I should have added a charge controller a long time ago. They are cheaper than I thought.

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