Solar Powered Mobile Charger Circuit

Now days mobile phones are very important part of our life.

But charging it always need electricity.

If we are outside or village side where there is no power then problem comes.

This small Solar Powered Mobile Charger Circuit can give 4.7V output from 9V solar panel.

It is simple and with low cost circuit for emergency charging.

Circuit Working:

Solar panel gives 9V DC supply when sunlight falls.

Diode 1N4007 is used for blocking reverse current from battery to panel at night.

Capacitor C1 works as filter and smooth the supply.

Resistor R1 and LED1 is just for indicator to show circuit is working.

Resistor R2 control base current of transistor Q1.

The Zener diode is main part and it is 5.7V, so it regulate output voltage.

Capacitor C2 is used for stability and remove ripples.

At output side we get around 4.7V which is suitable for charging mobile phone.

Formulas for Solar Powered Mobile Charger Circuit is shown below:

Base current through R2 560Ω into TIP122 transistor.

TIP122 Vbe (Darlington) = 1.2V (two junctions)

Zener Vz = 5.7V

Voltage across R2: VR2 = Vin − Vbe − Vz = 9 − 1.2 − 5.7 = 2.1V

Base current Ib = VR2 / R2 = 2.1 / 560 = 0.00375 A = 3.75 mA

Power in R2: PR2 = VR2 × Ib = 2.1 × 0.00375 = 0.0079 W which is safe.

To build a Solar Powered Mobile Charger Circuit follow the below mentioned steps:

Gather all the parts as shown in circuit diagram.
Connect solar panel 9V positive to diode D1 anode and negative of panel go to ground.
Cathode of D1 connect to capacitor C1 positive and same point connect to resistor R1 and R2.
Other end of R1 connect to LED1 anode and LED1 cathode go to ground.
Other end of R2 connect to base pin of transistor Q1.
Collector pin of Q1 connect back to solar panel positive and diode D1 cathode point.
Emitter pin of Q1 give output 4.7V to mobile connector.
Zener diode anode and capacitor C2 negative go to ground.
Mobile charging connector take positive from emitter of Q1 and negative from ground.

If required we can upgrade Zener power rating and maybe add protection resistor or heatsink transistor otherwise it might damage.

This is an easy Solar Powered Mobile Charger Circuit using 9V solar panel.

It gives about 5.7V regulated voltage with Zener diode.

It is useful for charging small mobile phones when there is no electricity.

This circuit is good for learning and small emergency use.