Thermo King ThermoLite Solar Panels help lower operational costs by reducing diesel APU run time by 20 to 30 percent, extending battery life to five-plus years, and help match auxillary power unit (APU) and tractor preventive maintenance, the company says. Solar power offers many benefits for fleets running without APUs, such as reducing jump starts and road calls, powering diesel-fired heaters, keeping tractor batteries healthy, and making sure electronics stay powered up even over the weekend. The high-efficiency solar cells produce abundant power, even in low-light conditions.