This article explains about how to make your own solar based
mobile phone charging unit. The design is very simple and completing this should not
take you more than 2 hours.
List of components
required:
1.
Solar panel : 3W,6V panel
2.
Sealed Maintenance free lead acid battery:
6V,4.5AH
3.
Diode: IN4001
4.
DC -DC Step Down Buck Converter KIS3R33S Module
7V- 24V to 5V /3A
5.
USB based mobile charging cable( Normal data
cables will not work)
6.
Connecting wires
7.
Soldering kit
Circuit connections diagram:
Working principle:
Mobile phones have inbuilt batteries and they need to be charged
every few days or every day depending on how often the mobile is used.
Batteries can be charged only with Direct current whereas the electricity we
get in our normal household sockets is Alternating current. A mobile phone
charger does the job of converting AC to DC and keeping the output voltage and
current levels suitable for mobile charging. Chargers typically have
efficiencies ranging from 60-90% depending on the quality (This is why some of
the chargers get heated up quickly)
On the other hand solar panels convert solar energy to DC
electricity. With suitable circuitry we can store this DC electricity in an
external battery and charge the mobile phone when ever required.
The selection of solar panel and battery depends on various
parameters like number of mobiles to be charged and the voltage levels of the
battery etc. We have used a 6V, 4.5AH battery which can charge a typical smart
phone once every day. A 3W 6V solar
panel is chosen since that is enough to charge the external battery in 7-8 hrs.
The solar panel is directly connected to the battery with a diode in between to
avoid reverse flow of current from the battery to the solar panel when there
isn’t enough sunshine and during night time.
A DC-DC converter module is used to convert 6V battery
voltage to 5V output since mobile batteries are very sensitive to charging
voltage and current( a normal car battery regulator can be used but the efficiency
is very low)
Construction:
·
As shown in the circuit diagram, connect the
positive end of the solar panel to the positive end of the diode (silver ring
on the diode represents negative) and the negative end of the diode to the positive
of the battery. The negative end of the solar panel can be directly connected
to the negative terminal of the battery.
·
Solder the terminals and use insulation tape to
make sure shorting of terminals doesn’t happen.
·
Identify the input side of the DC-DC converter
and connect positive and negative of the battery to the positive and negative
of the DC-DC converter input respectively.
·
The output of the DC-DC converter is a USB port
where the charging cable is inserted. (Note: Normal data cables do not work so
a simple charging only cable should be used)
·
If the connections are proper, you should be
able to see a red light glow on the DC-DC board and your mobile phone should
display charging.
·
We had used a voltage and current measuring
device called a charger doctor at the output to verify if the voltage and
current levels are in the suitable range. This unit is not required.
Try
this fun project and let us know your experience or queries in the comments
section below.
Where to buy?
1.
Solar panel : http://www.amazon.in/Sparkel-Solar-Panel-meter
connection/dp/B01EB0C06Q?tag=googinhydr18418-21
2.
6V battery : http://www.amazon.in/6v-4-5Ah-SMF-VRLA-Battery/dp/B00MPJ66UM/ref=sr_1_1?ie=UTF8&qid=1474624382&sr=8-1&keywords=6+v+battery
3.
DC-DC converter : http://www.amazon.in/Converter-KIS3R33S-Module-Replace-KG106/dp/B00YURPEL4?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00
4.
Diode IN4001,connecting wires, soldering kit and
charging cable : Any regular electronics store
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