Gel battery connected to mobile power supply
240KW/400KW industrial rooftop - commercial rooftop - home rooftop, solar power generation system.
Alkaline batteries are capable of considerably less. When connected to an Arduino, the 9V battery goes through a linear regulation to lower the voltage to an acceptable level. This alone would tax a typical 9V battery. It would do better with 3 AA batteries connected to the 5V input on the Arduino bypassing the regulator.