Efficient automatic solar garder lights circuit with minimum components the best deal is that is completely auto and the Solar panel acts as a light detector. Switches the Lamp off at Dawn, charges the battery during daytime and switches the LED lights ON at dusk providing 100 Lumens illumination during the night.
The solar panel must provide 5.5V and 150mA. Assuming a 3.7V/1500mAh battery the charging will be complete in 8 hours at 200% capacity @ 180 mA. With 10 LEDs the power consumption would be 90 mA/hour providing a 10 hours illumination with light levels of 50 lumens to 60 lumens. With 20 LEDs the light intensity will be 100 to 120 lumens.
You can use any number of LEDs and battery capacity too. This would directly provide you the amount of illumination and time for illumination. If you use higher capacity battery than that recommended the solar panel current should be increased proportionately. Current provided by solar panel should be 10% of battery capacity.
Bill of material for the solar garden lights