Two inputs over a diode. AC-adapter, Solar. ~14-20V
Two PWM circuits, one controlling battery, charge 
float boost etc. Temperature compensated charge-process.
The other circuit is controlling low-voltage disconnect,

Current measurements w. two HALL sensors for load and
battery. 

USB-port for host communication w. open serial API for 
extensive monitoring and operation

Rugged components, power-FET's. MCU is the latest Atmel
low-power MCU.