Matrix Industries has unveiled the second generation of its body-heat-powered smartwatch that you don’t have to charge. As long it is touching your skin, the PowerWatch 2 doesn’t need a new charge. The new PowerWatch 2 gathers additional energy from solar power, which all but erases the fear of running out of battery power.

It’s all in the name of paving the way for wearables that never need charging, and it will be on display at CES 2019, the big tech trade show in Las Vegas next week. Menlo Park, California-based Matrix Industries launched its first PowerWatch in November 2017, after a successful Indiegogo campaign and six years of research. The new watch is expected to ship in June.

The idea came from materials scientists who wanted to change the way we harvest and use previously wasted energy. The first model didn’t look like much, but it had no frills in its graphics because of the need to save power.

Image Credit: Matrix Industries

The solar cell brings an increase in power, allowing the PowerWatch 2 to come standard with a completely new set of functions, including features like built-in intelligent heart rate monitoring capabilities, a full-color display, and onboard GPS, said Matrix Industries CEO Akram Boukai, in an interview with VentureBeat. PowerWatch 2 is available for preorder today, starting at $200 for early bird preorders ($499 at retail). The previously announced PowerWatch is also $200, and PowerWatch X (with notifications) is $280.

“The main feedback from our first generation is that people wanted more enhanced graphics and other features like GPS, and the solar cell is the way to help with that,” said Boukai. “We were able to integrate an amorphous silicon solar cell in the shape of a ring around the watch dial, as part of the display.”

Some of the early interest so far came from individual members of the military, who said they could use the watch while on deployment without having to worry about charging it.

PowerWatch 2 introduces the first full-color LCD display powered by thermoelectric and solar energy, as well as always-on GPS so you can map out your run, hike, or ride. It allows you to leave your smartphone at home.

With the introduction of HR and GPS functionality, PowerWatch 2 — and its iOS/Android companion apps — can now provide users with even more useful health and fitness metrics, including pace, distance, steps, sleep, cadence, and what the company calls the most accurate calorie count industrywide. PowerWatch 2 will also integrate third-party fitness platforms like Apple HealthKit and Google Fit, and is water resistant up to 200 meters. It isn’t that bulky, with a diameter of 44 millimeters.

“If you go out for a run, the solar helps take over the power, and so if you use GPS for 45 minutes to an hour, it should be good,” Boukai said.

The original model harvested energy from body heat, using a chip with a thermoelectric energy converter. Matrix Industries engineered its advanced thermoelectric generators to operate with extreme efficiency. It created more efficient conversion circuitry to power the electronics and charge the internal battery. And its thermal design is built to harvest the small amount of heat available to the wearable device.

Boukai said the outside of the wrist is a bad place to harvest energy because it doesn’t produce nearly as much heat as the head, the bottom of the feet, or even the inside of the wrist. The whole secret is maintaining a temperature difference between the part of the watch that touches your skin and the part on the other side. The process takes heat from your wrist and expels it from the other side of the watch.

Image Credit: Matrix Industries

The company found a semiconductor material that can conduct electricity but does not transfer heat easily. The team created the material by introducing defects into the material at a nano scale, or a billionth of a meter. This material produces a voltage when there is a temperature difference between the two sides of the chip.

When you take the watch off, the data is stored in memory, and the device goes to sleep. When you put it back on, the watch returns to where you left it. It also has an always-on power meter that tells you how much electricity your body heat is producing. This means it can accurately calculate how many calories you are burning.

While PowerWatch 2 increases the amount of energy available to the charge-free wearable, Matrix’s materials science and hardware engineers were able to also further miniaturize both the thermoelectric (TEG) and solar cell processes, decreasing PowerWatch 2’s weight and size even more while maintaining the rugged aluminum build.

“PowerWatch 2 reaches feature-parity with other industry wearables,” said Douglas Tham, chief technology officer of Matrix Industries, in a statement. “Our team worked tirelessly to create an all-purpose smartwatch that is perfectly jam-packed with new functionality and bonus features like gesture recognition and haptic/audio feedback.”

Matrix Industries will also show at CES 2019 its new PowerStation, a standalone patented device that generates energy from the ambient air around it. Both PowerWatch 2 and PowerStation are built with proprietary Matrix modules, including the Matrix Gemini TEG and Matrix Mercury Boost Converter. PowerStation also uses Matrix’s new Luna Phase Change Material, a revolutionary material that converts time-varying temperature fluctuations into a spatial temperature gradient.

Boukai and Tham, who met at Caltech, cofounded Matrix Industries as a materials science startup in 2011. They saw that wearables had a problem with poor battery life and so they pivoted to making a smartwatch, focusing on shrinking the bulky electronics.

The company raised $1.64 million in an Indiegogo crowdfunding campaign in January 2017 and raised nearly $30 million in total funding. All told, it took in more than $24 million in venture capital from backers such as Khosla Ventures. The company has 16 employees. The added staff helps with things such as bringing firmware in-house for more reliable and frequent updates.