Harnessing the Sun for My Doorbell: How a $17 Solar Panel Delivered Infinite Battery Life

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Trust, but verify.

I was asked to help set up an honor box along a popular trail here in the UK. You know the setup — a box stocked with cakes, drinks, and snacks for tired hikers, who are then trusted to pay for whatever they grab, either by dropping cash into a box or using a contactless payment method.

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As much as I’d like to believe that most people are decent and act with good intentions, there’s no denying that a few bad eggs exist. So I recommended adding a security camera to the box. I had a battery-powered cameras collecting dust in my office, so putting one to use seemed like a natural solution.

The catch is, these cameras would need to be removed and recharged every few weeks. While it isn’t exactly strenuous work, it is “another thing on the list to remember.” That got me brainstorming — could I improvise a setup and harness energy from the sun?

I still had a pair of compact EverExceed solar panels that had been sent to me for review, but I hadn’t tested them yet. Would they be up to the task? There’s only one way to find out!

Designed for outdoor use

I typically have low expectations for compact solar panels. Most of the ones you encounter, bundled into power banks or other budget accessories, feel more like a marketing gimmick than a functional charging solution. Honestly, I’ve encountered cheap solar chargers that actually drain the connected devices instead of charging them!

These panels were rated at 5W, measured roughly 7 x 6.5 inches, and came with a 10-foot cable tipped with a swappable microUSB/USB-C connector. The manufacturer states they’re IP65-rated for water resistance and rated to operate across a temperature range of -4°F to 122°F.

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Seems like just the thing for British weather!

The panel also ships with a 360-degree adjustable wall bracket. Although it’s largely plastic, it’s strong enough to handle the demands of the job.

The package includes screws and wall plugs — the essentials, for the most part. Well, aside from a drill, the right drill bit for whatever surface you’re attaching to, and a screwdriver. You’ll also want a way to tidy up the cable so it doesn’t whip around in the wind.

Nothing ruins a cable faster than letting it rub against a surface in the breeze for a few weeks. And if the cable fails, replacing it would mean dismantling the whole panel.

For a neat, professional finish, you could opt for cable clips (either self-adhesive or nail-in), but since I was mounting it on a wooden shed, I went old-school with duct tape and a staple gun.

Thoughtful placement makes all the difference

You’ll want to put some thought into where the panel goes. With 10 feet of cable at your disposal, you’ve got decent flexibility. If you’re in the northern hemisphere, aim for as close to a south-facing orientation as possible, and steer clear of shaded areas (the less direct sunlight you get, the more critical it is to squeeze every bit of energy from available light).

The tilt angle should roughly match the latitude of your location (or 45 degrees if you’d rather skip the calculations).

There are apps to help with this. I used the built-in Measure app on my iPhone for both tasks, but if you’re on Android, you’ve got plenty of options available as well.

It delivers on its promise

Hooking up the camera is straightforward. Decide where you want it mounted, screw the bracket into the wall, attach the panel, angle it toward the sun, route the cable to the device you’re powering (don’t forget to include a drip loop where the cable passes through a wall into a building or shed — this prevents water from running along the wire, and you can seal the hole with silicone caulk), and finally plug the cable into whatever needs charging.