@▷ LED Solar Lantern Lights | Diagram for Schematic

LED Solar Lantern Lights

solar led lantern ideaCircuit of the LED solar lantern lights presented here is built around one 6V/1W Solar Panel (PhotoVoltaic Panel) and a 4V/800mAh Lead-Acid Battery. Here, commonly available 5mm White Straw Hat LEDs are used as the light source.

how does the solar lantern circuit works

DC 6V supply from the solar panel is fed to the rechargeable battery through diode D1 (1N4007) and resistor R1 (15R). Diode D1 functions as a reverse current protector and resistor R1 limits the battery charging current to a safe value. Transistor T1 (BC548) is here wired as an automatic switch to control the LED driver transistor T2 (SL100). T1 disables T2 when the circuit receives sufficient power output from the solar panel.

Solar Lantern Lights Circuit Schematic

LED solar powered lantern lights schematic
LED solar powered lantern lights schematic

Switch S1 is an ordinary power on/off switch. Finally, resistor R4 determines the operating current of the white LED (LED 1 – LED 20) assembly. No-load voltage of the solar panel is near 7.2Volt. When connected with the circuit, the PV panel gives around 170mA of current at 6VDC output in middling sunlight, which is more than enough for this circuit. When fully charged, no-load output voltage of the 4V lead-acid battery is near 4.6Volt. According to datasheet, Forward Voltage of the 5mm (actually 4.8mm) White Straw Hat LED (used here) is 3 to 3.2volt, and maximum Continuous Current is about 20mA (Peak Current 30mA).

LED Solar Powered Lantern Notes

  • The design of this solar powered lantern is flexible! So, you can modify it as per your requirement & taste. However if you wish to change the PV panel and/or the re-chargeable battery, keep an eye on resistor R1. This also applies to resistor R4 when you are playing with the number of white LEDs
  • In the LED solar lights prototype, medium-power transistor SL100B (fitted with a small heatsink) was used as T2. This part number is not very crucial. You can try near-similar transistors as well
  • This solar lantern can also be charged from any 6VDC power source, capable of delivering the demanded current output