Carrier Transicold’s newest charging system for transport refrigeration unit (TRU) batteries is looking skyward for power, and it takes up limited space on top of the TRU itself.

The TRU-Mount Solar Charging System delivers 2.0-amp power by combining silicon cells and a high-performance charge controller.

It all fits on the narrow, curved tops of Carrier Transicold X4 and X2 trailer refrigeration units and Vector 8000 and 6000 units. And a charge controller is integrated into the panel itself, simplifying installation.

The low position on the TRU helps to prevent overhead scrapes, the company adds. Cell efficiency is also said to be protected by not suspending the TRUMount over the exhaust path.

The solar panels have three layers. The light-trapping upper layer will resist scratches, weather, and impact. The middle layer made of monocrystalline cells is designed to maximize output and minimize power losses from intermittent shading. And a copper bottom layer serves as a heat sink to control panel temperatures.

Compared to previous systems, this version provides up to 18% more power for the complete charging of a 12-volt TRU battery, the company says.

Solar panels have been used to offset the battery demands of ancillary devices including fuel-level sensors, interior trailer lighting, and telematics. That can help prevent the power draws that actually drain the battery too low to start the TRU engine.