Solar power has been around for centuries, dating back to the 7th century B.C. Today it is common to see rooftop solar panels powering homes, schools and offices, and solar arrays helping to fuel cities and towns. One of the exciting new advances in solar technology is its use to run Auxiliary Power Units (APUs) on trucks and buses.

Power generation for solar APUs starts with solar panels that are mounted to the top of the vehicle or the vehicle’s trailer. These panels capture the sun’s light and convert a portion of it to DC (direct current) electricity. The DC electricity then goes to a solar charge controller to maximize the power output of the solar panels. This power is then directed to auxiliary batteries, which power the APU on the vehicle. The APU provides power to run vehicle climate control, liftgates, lighting, computers, and other auxiliary systems.

Solar powered APUs burn no fuel and generate no emissions. Another benefit is that they will charge batteries any time the solar panels are exposed to the sunlight. This allows batteries to be charged over weekends or periods of time where the vehicle is not being used. This also ensures that battery banks are fully charged heading into night hours to ensure that the APU can be used through the night as well. A white paper recently released by eNow Inc. at the Mid America Trucking Show provides new evidence of the greater fuel and cost savings potential of solar powered APUs compared to conventional auxiliary power systems.