solar charger with arduino

This tutorial shows how to create a time switching battery powered solar charged circuit, which is used to power an Arduino Uno and some peripherals (sensors, communication modules, etc.).

If you want to design a remote data logger, power supply is always a problem. Most of the times there is no power outlet available, and that forces you to use some batteries to power your circuit. But eventually your device will go out of batteries... and you don't want to go there and charge it, right? So a solar charging circuit was proposed to user free energy from the sun to charge the batteries and to power your beloved Arduino.

First you'll have to assemble the solar powered battery charger circuit. This uses the energy from some solar cells to charge the batteries, and boosts the voltage from it to the 5V used by the Arduino Uno.

This circuit was based on the awesome tutorial by deba168, Solar powered Arduino weather station.

Solar cells are connected to the input of the lithium battery charger (TP4056), whose output is connected to the 18560 lithium battery. A 5V step-up voltage booster is also connected to the battery and is used to convert from 3.7V dc to 5V dc. You can check the connection between the components in the picture.

Some pins were soldered to the bottom of both modules (TP4056 and booster), to allow easier connection to a breadboard. If you don't to use a breadboard, you might connect the components with wires and solder them.

At this point you may already power your Arduino Uno, connecting it to booster's USB connector, and your Arduino will work until the battery is depleted. When there is enough sun light, the battery will automatically start to charge.

Notice that the TP4056 input is limited between 4.5 and 5.5V. I this circuit there is no voltage limiter between the solar panel and the battery charger. A Zener diode might be used limite the voltage and protect your circuit.