Use li-ion battery pack at night to detect motion and light 300ma led for ~20 minutes. charge battery with solar panel at day time.

12 cell solar panel delivering 6v and roughly 3 amp peak power to four 18650 battery pack, charging during day light. I am using two parallelly connected TP4056 charger module for charging, It also protects batteries from overcharge, overcurrent and over discharge.

TP4056 module powers PIR sensor module that is used for motion detection, custom made 555 timer in monostable mode on perfboard and 300ma led.

555 timer gets trigger from HC-SR501 PIR module, changes high signal to low using simple BJT transistor not gate and turns on 555 timer. Timer output connected to MOSFET lights 300ma LED. You can adjust duration of ON state using potentiometer.