I tried an experiment. I had a 100 Watt UHF repeater, that was little used. It consumed 100 Watts in standby and 400 Watts when transmitting. It cost $40 USD/Month to sit idly, with no TX time, in 2012. So, I decided to play with solar off grid with battery. I scaled back the TX power to a 25 Watt repeater, 12 volt system.
The first 100 Watt mono panel, developed micro cracks within 3 years. The voltage out of that panel, dropped below the rated output and the problem was visible in the battery capacity. The manufacturer (Renogy), fought me on warranty, because the short circuit current met the expected spec for its age. The two specs they base warranty on are, Open circuit voltage and short circuit current, in full sun. Open circuit V is ZERO load. Short circuit current is FULL load. However, Ohm's law, dictates that the lower the voltage, the higher the current in a circuit. It took several months of back and forth to finally convince them their criteria for panel warranty was faulty, that no load voltage proves nothing, to get a replacement. I have replaced the batteries several times since 2014 when this was built. I am on the 3rd charge controller.
I thought it was cool and "green". It proved to be a headache and not so green after all. About a week ago, I modified a 85% efficiency switching power supply. It consumes 12.6 Watts on standby and 140 Watts in TX. I no longer need to wait for the batteries to charge in the winter and fewer headaches. Probably less carbon footprint in the long run and now we are using it.