You can preserve power by following below guidelines:

To use the solar panels a DC/DC adapter needs to be inserted between the terminal and the UnatSolar Power Pack. The Thrane & Thrane DC/DC adapter Article code 102228 is the only adapter needed between the Power Pack and the EXPLORER 100/110 (WorldPro 1000/1010) terminal. The adapter has a LED showing when the input power is high enough to generate 12 volt output.