The regulator was designed for a 10W to 50W 12V solar panel bit the electronics can be easily adapted for higher power.
A switching power supply (SMPS) module was added to reduce dissipated power and to improve efficiency (the original circuit was based on a 7805). This SMPS enables also the use of a 24V input voltage.
The charging of the battery is controlled by a microcontroller (MCU) that also cuts off the load when the battery gets discharged too much. When the battery is charged up to at least again 12V the load is automatically reconnected.