Who Needs TV Remote Batteries? I Saw 'Passive' Solar Tech That's Making Them Obsolete

Ambient solar tech is nothing new, as anyone who's used a calculator knows, but it's getting better.

A green mechanical keyboard with a black solar cell on the side of it.

This mechanical keyboard isn't powered by batteries or with a cord, but by using the solar cells on the right side of it.

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The solar technology Ambient Photonics presented at CES 2024 (by the way, here are our favorite CES things) is cool and new and innovative. The whole time I was touring the company's booth, my mind kept drifting back to the blue TI-108 calculators we would use on math tests when I was in elementary school.

The fact is, a solar cell that powers a small device using light it captures indoors isn't all that revolutionary. I probably have a calculator powered by solar cells that is older than I am, but what Ambient Photonics demonstrated takes things to another level.

These solar cells, made of two sheets of glass with a dye in between, capture energy from even very low-light indoor environments. The big change compared to the amorphous silicon solar cells in those old calculators is that these cells can yield about three times the energy. That opens up the possibility of powering things that do much more than arithmetic.

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Samsung has been including remote controls with solar panels many of on its TVs since 2021, but Ambient Photonics wants to replace batteries with solar in a much wider array of devices. In its booth I saw examples of keyboards, computer mice, smart home sensors and other devices that used its solar cells. You can't buy any of them yet, but the company announced partnerships at CES with Primax, to develop an ambient solar mouse, and with Google, to create a "new consumer product" for launch this year.

Powered by indoor light

Ambient Photonics' solar cells are specifically designed for the low-light environments of your desk, your bathroom and your living room. Chris Turkstra, the company's chief product officer and chief marketing officer, told me this technology isn't really designed to generate enough electricity to power your larger appliances. The goal, instead, is to replace all those AA, AAA and lithium-ion batteries in little things around your home. 

The company makes solar cells in a trio of sizes, ranging from one barely bigger than a thumbnail to one about the size of a dollar bill. They can determine what kind of surface area is needed based on the device's power demands and the expected light conditions in the area where it will be used. Something that will be used in a brighter area can probably get by with a smaller solar cell than something used in a darker room.

Four small remotes laying on a display counter.

The first three remotes are powered by solar cells, but the last one has batteries. You can see how thin the solar cell ones are.

Jon Reed/CNET

These devices don't necessarily turn off the second it gets dark. The solar cells will charge a capacitor or supercapacitor to hold energy as needed. Unlike batteries, those capacitors recharge virtually instantly, Turkstra said.

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Ambient Photonics even had a display that allowed you to see the charge in a capacitor connected to two solar cells. A dial lets you change the energy intensiveness of the "device" the cells were powering, and I saw how the energy dynamics changed as I rotated it to a more intensive device and a less intensive device. These solar cells, again, were generating power based on the lights in the rafters of the Venetian Expo's exhibit hall in Las Vegas. If I put my hand over them, I saw how the power production dropped.

Say goodbye to batteries, sometimes

A lot of the models Ambient Photonics displayed were impressive in their size. By that, I mean that they were small and thin, almost minimalist. An example of a TV remote was thin and flat like a wafer, without the bulge of a battery housing. 

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Batteries, Turkstra said, have defined the size and shape of consumer electronics for decades. Much of the mass of a remote control or a smartphone is battery cells. Devices that can run entirely on ambient light and don't need batteries are freed from those design constraints.

Device manufacturers can actually combine these cells and batteries. Ambient solar cells can just extend their lifespan, or batteries can be used as a backup. For example, a device that might burn through a battery in a year could see its life extended to the point where you'd only have to replace a battery every five years. 

Right now, there aren't any devices on the market that use Ambient Photonics' cells, but Turkstra said those should be available later this year. 

Looking for more solar tech from CES? Check out this technique that can inkjet-print solar cells

Article updated on January 11, 2024 at 9:43 AM PST

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Jon Reed
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Jon Reed is an editor for CNET covering home energy, including solar panels and energy efficiency. Jon has spent more than a decade making a living by asking other people questions. He previously worked as an editor at NextAdvisor, focused on home loans and the housing market; as a statehouse reporter in Columbus, Ohio; and as a reporter in Birmingham, Alabama. When not asking people questions, he can usually be found half asleep trying to read a long history book while surrounded by cats.
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