DIY Solar Panel Powered Charger

About

This is a novice guide to build a Solar panel based mobile charger. Recently I built(assembled) a Solar panel based mobile charger, under ₹ 700 which is pretty decent in performance and gives an output of 5V and 750mA.

Having not much practical experience in electronic, I had to couple of days on understanding the possibilities of achieving it, then some time on assembling it on my own.

Components Used

Power Source:

Apparently the solar panel. A 5W Solar panel available in most of the local electronic shop for less than ₹500, was enough for a decent charging. The size is ~ 30 X 20 cm. Almost a size of a laptop, but it is fine for me, after all, an experimental project for my own use. When kept in the morning sunshine, the output is nearly 4.4W(10V X 440mA).

A Converter:

The output that comes from the solar panel cannot be used to charge the mobile directly. The smartphones requires 5V of input to charge. And how fast it is getting charged, depends on the amperage.

There are 2 options to get it converted to the required voltage,

  • A Buck Converter, is to DC as a transformer is to AC. It helps to convert a DC voltage to a desire DC voltage, by increasing/reducing the current, thus maintaining the energy.(When the voltage is stepped up the current will be stepped down and vice-versa)
  • A 78XX Voltage regulator, just reduces the input voltage to XX but maintains the same input current, and the excessive energy will be dissipated as heat.

Since a Buck converter is efficient with close to 90% efficiency, I chose Buck converter. I got this under ₹140. Also there is an adjustment available in this converter, which helps to adjust the output voltage to desired voltage.

An O/P Interface:

My main intention was to have a mobile charger. So I used a USB female, which can be utilized by many other electronic equipments such camera, power bank, etc.

When you keep the female USB in the way to have the metal connectors faces up, out of 4 metal connectors, the right extreme of the USB is Vcc and the left extreme is GND. For our case, the Vcc is expected to be 5V wrt GND.

USB Spec

Misc:

Required wires and adapter-pair/Connectors. Utility equipment such as Multimeter and a Soldering gun.

Assembling Them:

Since most of the things are readily available, assembling them is our major work. I soldered all the components with adapters so that I can assemble or change any of the components when needed(modular).

And as I assembled all these, I am able to charge my mobile using a data-cable.

Soldered Final Circuit

Performance:

I am getting an output of 5V and 0.8A, which is 4W, from a solar panel delivering 4.4W. So I am getting almost 90%of efficiency.

Daily, I am able to harvest enough energy to charge my 3000mAh mobile battery.