DIY solar powered chargers to juice up your cellphone

The concept

Instead of using your regular plug-in charger for your cell phone, try building a DIY solar charger in just a few easy steps. Apart from being inexpensive, these chargers which harness the energy of the sun to juice up your cell phone also help in protecting the environment and reduce dependency on fossil fuels.

The inspiration

All of us have experienced embarrassing times when the battery of our cellphones went flat in the middle of an important conversation. Even if you happen to carry your charger along, most times you don’t find a power outlet nearby. This is where the the solar powered chargers come in. These chargers, powered by green energy, are reliable and some are even portable allowing you to charge your cell phone on the go. Now you will never run out of charge on your phone as long as the sun is up shining brightly.

Eco credentials

With the ubiquity of mobile phones, solar powered chargers can have a significant positive impact on the environment if more and more people start using them. Not only do these chargers help protect the environment, they are reliable and also will not burn a hole in your pocket.

Feasibility

Solar powered chargers are now getting popular but are still a bit too expensive. Instead you can make your own DIY solar power charger in a few easy steps. All you would need is a solar cell, a car power outlet socket, a project box, some Velcro and few other easily available materials. Additionally, a soldering iron and some solder is needed to solder the wires together. Simply twisting them will also do the trick but make sure to cover up the exposed wiring with electric tape.

Related trends

1. ALTOIDS Tin solar cell phone charger

Turn a ALTOIDS Tin box into a solar charger for your cell phone. Additionally you will need solar powered LED landscaping lights for the solar cell and few other old, recycled parts.

Things you will need:

a) An empty ALTOIDS Tin box

b) A small solar cell

Most cell phones can use a 3V to 6V solar cell. Read the back of your wall charger and find out the output voltage to match it to the solar cell you choose.

c) An electrical tape to cover the exposed parts of the wires

d) Velcro to stick the parts together

e) A plug-in charger

f) Soldering iron

g) A voltmeter to match the voltages and to check polarities

Making the solar cell

For your solar cell, use the one out of a solar LED light. Take out the plastic cover and cut the solar cell free of the circuit board and battery. Scrape off the plastic bits on the back of the solar cell with a hacksaw blade. Find out the polarity of the cell with the help of a voltmeter. Check the polarity of the plug-in charger and mark the + wire. Cut the wire in half. You will only be needing the side of the wire which goes in to the cell phone.

Preparing the ALTOIDS Tin

To protect against shorts, stick electrical tape on the inside of the tin. Solder the wires of the charger to the solar cell. Make sure that you solder the + to + and the – to -.

Attach the solar cell to the lid

Stick one piece of Velcro to the center of the solar cell and the other piece to the center of the lid. Cover all exposed contacts and wires with electrical tape.

The final step

Attach the solar cell with the lid and place it under the sun. Your ALTOIDS Tin solar charger is now ready. It is portable so you can carry it in your bag and use it whenever you need to charge your cell phone.

2. DIY solar powered mobile phone

Follow these simple instructions to build your own solar powered mobile phone.

Things you will need:

a) The Motorola F3

Probably the cheapest phone around it’s affordability and ruggedness makes it suitable to be incorporated in the project.

b) Solar panel

It should be rated 4.5 V or above with dimensions around 100mm x 40 mm.

c) A Schottky diode

You can use 1N5817 or equivalent as long as you can solder wires on its ends.

d) Enameled wires

e) Soldering iron

f) Pen knife

g) Aluminum tape

i) Epoxy

j) Hand drill

k) Super glue

Getting it started

Drill small holes on the battery cover of the phone to attach the solar panel to it. Roughen the surface of the cover with some sand paper as it helps in adhesion. Next, spread the epoxy and attach the panel in the correct orientation.

Wiring the diode

A solar cell modeled as a current source in parallel to a diode, the charging current is very small. You can measure the open circuit voltage and the short circuit current of the solar panel by simply shorting your multimeter across the panel terminals. Remember that when charging takes place, the net charging current must not be more than the measured short circuit current. For safe charging, charge the battery at 70 mA. It is advisable to charge the cell phone only when the battery indicator shows at least one bar below the full charge.

Remaining wiring

Wire the phone battery contact terminals in such a way that the battery cover along with the solar panel can be taken apart easily. Take care to maintain good electrical contacts.

Final words

The phone can be used for about a whole week before you need to recharge the battery. It is cost-effective and most helpful when you are out camping. The model can be further improved by using boost converters and solar panels with smaller dimensions.

3. DIY MightyMintyBoost: Solar iPhone charger

Imagine the amount of energy that can be saved if all the 30 million Apple iPod/iPhone units in the world were charged by solar power. The MightyMintyBoost solar iPhone charger is small, easy to make and is solar powered. It accepts input voltage from 3.7V to 7V. A larger solar cell of about 6V will charge your iPhone in about 5.5 hours and your iPod in 4 hours.

Things you will need:

a) MintyBoost kit

b) Lithium polymer battery charger

c) Lithium polymer battery

d) Velcro

e) ALTOIDS Tin

f) Solar Cell

g) Soldering iron

h) Scissors/pen knife

i) Wire cutters

j) Pliers

k) Multimeter

l) Electric tape

m) JST connectors/wires

Building the MintyBoost Kit

Solder a JST wire to the MintyBoost PCB after you have checked the polarities. This wire connects the MintyBoost and the Lithium polymer battery charger circuits. Test the MintyBoost by connecting the battery pack and the charger circuit. Next, cut a notch in the ALTOIDS tin to fit the USB port. Mount the PCB to the ALTOIDS tin by some adhesive.

Incorporating the battery and the charger

Cut another notch in the ALTOIDS tin for the charger and attach the charging circuit to the bottom of the ALTOIDS tin with adhesive. Connect the battery and the MintyBoost PCB to the charging circuit.

Connect the solar cell

You can add connect the solar cell in different ways. One way is to shorten the connector leads and plug the barrel plug on the charging circuit. Another way is to replace the connector with another one and and plug it into the 5V marked third connector to the charging circuit. Now, using Velcro, mount the solar cell on top of the ALTOIDS tin. Your MightyMintyBoost charger is ready to be used. Set it under the bright sun and let it charge. After it is fully charged, connect it with your iPhone, iPod or USB powered device.