Solar Street light circuit explanation.

[Besto]

Hi,
The schematic attached to this thread is a circuit design of a solar street light. I understood some part of it. But I am confused with other parts.Can anyone Help?

In the Circuit I understood how the LED is turned on and the voltage sensing at solar pannel.
I need to know about the section with Q11, Q13, Q14, Q15, Q16.

I was retracing the circuit from this board.

 

[BradtheRad]

It's not easy to identify which transistors conduct to or from the battery at which times. I guess the IC is the decision-making component which determines whether the battery should be charged from the PV panel, or whether to turn off charging when it is unsuccessful.

Some resistor networks appear designed to respond to certain volt levels coming from different directions.

Some resistor networks appear designed to limit transistors to certain current levels.