Researchers at New Zealand’s Massey University have developed a robotic lawnmower with three 50W solar panels and a 20Ah lithium iron phosphate (LiFePO4) battery. Two of the PV panels can be retracted and stacked inside the robot. They slide out when the batteries need to be charged.
The Sun Scout Pro has three fully integrated 50 W solar panels that charge 20 Ah Lithium Iron Phosphate (LiFePO4). One of the PV panels sits on top of the robot, while two additional modules are attached to a sliding, retractable structure.
“By stripping the solar module down to its essential features and implementing more efficient shielding structures together with our flagship stacked panel assemblies, we were able to create lightweight solar panel solutions that are perfect for mobile applications,” the research team says on the product’s website. .
The maximum power point tracking (MPPT) voltage range of the PV system is 15 V to 45 V. The efficiency of the MPPT solar charger is over 99% and the maximum input power of solar energy is 400 W. The nominal voltage of the LiFePO4 battery is 38.4 V and the energy capacity is 768 Wh. The team claims it has 5,000 charging cycles.
“Assuming that the Sunscout Pro charges its battery four times a week on average, which corresponds to 208 times a year, the guaranteed 5,000 charging cycles would provide up to 24 years of use,” says the research team.
When the robotic lawnmower’s batteries are low, it slides out its two extra PV panels and follows the sun to recharge faster. Average battery charging time is four hours at 70% discharge. The dimensions of the device are 850 mm x 450 mm x 400 mm and the weight is 45 kg. Its cutting width is 40 cm and the cutting height can be programmed between 25 mm and 75 mm. It mulches grass at a speed of 50 meters per minute and covers an area of 1,200 square meters per charge.
The concept was first developed in 2020 and its feasibility was reportedly confirmed by a Massey University study in 2021. The project underwent prototype testing in December 2022 and a working prototype was completed in January 2023. The Massey University team began building assembly lines in New Zealand and Germany in February of this year and is now trying to raise customer support on Kickstarter through the campaign. If successful, it plans to launch the product in June and start shipping in August.
The products come with a two-year warranty and cost $2,630, according to the Kickstarter campaign page.