The project is a Solar Charged USB charger, There is abundant sunlight emitted at this moment and we could use this light to charge several things such as batteries, cellphones and such more. I thought that this will be useful especially when we go into a long trip or such we wont loose power in our modern gadgets like cellphone that can be charged by a USB port or even powering up a USB fan.
This works by placing the project into the sun and let it charge for several hours to make it fully charged. Making this a portable USB power supply i used a 3 AA battery to power up the DC-DC boost converter. The boost converter wont put out a regular supply so I used a voltage regulator to make it a constant DC 5V output. The reason for a boost converter is to be able to use a small voltage battery like 1.2v AA NI-MH in series to not exceed 5 volts. Exceeding to 5v of battery will be hard for the solar panel to charge it. Casing is not a very big one and all components is fit inside so this is the one i used.
How does it work?
- Solar power is abundant at day time and we want to store as much as possible in our battery pack. when it is turned off it is constantly charging until it gets full but then if you will use it regularly then i recommend you to place a DC plug to charge your battery from the wall.
The reason for making this project is to have a portable charger and to charge it anywhere in the world. If you ran out of battery and you still have no outlet then we will use the Solar panel to charge our battery. But the disadvantage for this solar charger is that it takes couple of hours to charge.
this this solar panel gives out 200mA of current in full sunlight to charge a 2700 mAH of battery pack. to solve for the time it will take around 13.5 hours to charge it fully. to solve use the formula
Charge capacity 2700mAH
----------------------- = -------------------- = 13.5 hours
Current charger 200mA
Just cancel the mA and divide the numbers to have the answer.
2- How did I make it?
I got the idea from an article about sun power and charging a DC input with a Voltage regulator. This project was supported financially by my friend. My plan is to have a smaller casing and use 2 AA battery but the materials that is available did not permit my plans so i went with the flow finding alternative ways to complete this project, but still with my knowledge of Electronics.
3- Where did I make it?
This project was made in the house and was demonstrated in school, this project took me 1 day of finding the materials and 1 day to assemble and to trouble shoot it is a total of 2 days only. This project was able to help me charge my gadgets with the power of sunlight and may there be a time that we loose battery here is the project we need.
4- What did I learn from this project?
The biggest challenge is to find the things with creative knowledge. While building this project I have learned that nothing is easy if you don't strive hard for it. As my teacher said "Work Hard, Pray hard."
I am proud that i was able to make another successful project with what i have. If i had to make this project again I would upgrade this project by placing battery level indicator, charge limit and sunlight detector and so on. If i could even find parts that would be smaller it would be more portable.
Step 1: Materials
- 3 rechargeable battery (NiMH)
- 7805 Voltage regulator
- PCB (optional)
- Resistors (75k and 50k ohm)
- USB female PLUG
- 3.4v-8V+ DC-DC converter
- Battery holder (4 cell)
- Heat sink (optional)
- SOLAR PANEL (1w or higher Nomial voltage: 5v)
- Blocking Diode
- Soldering Iron
- Portable Drill
- Wire stripper
- Safety Gear
- Permanent Marker (PCB Development)
-Ferric Chloride (etching solution)
Step 2: Casing
1. draw the USB female plug in the place you want
2. Make sure everything fits inside with your design especially the battery holder
3. after making the sketch of the USB female plug drill the necessary hole for it.
4. make sure it fits, if not make adjustments.
1. draw the marks that needs to be drilled
2. make the hole to the needed mark.
Note: this is the very last step
1. Drill the necessary hole for the wire to go into the cover
Note: if you got the parts like mine do this step if battery case is fixed in.
Step 3: PCB Fabrication
just 3 lines for INPUT, GROUND and OUTPUT
Make another PCB with your desired design for the USB female plug
Follow the design like the one in the picture.
you can use a presensitized board or just use a marker to cover the marks in in the etching process (removing excess Copper)
Step 4: Wiring
Battery will be charged even though it is turned off.
the battery could be fully charged in approximately 13.5 hours via solar panel.
Connect the positive side of the battery to the input of the DC-DC converter
connect the negative (black) to the ground of the DC-DC Converter
connect the output of the DC-DC converter to the PCB with the 7805. the output will be connected to the input of the 7805 Voltage regulator.
the ground will be connected to the ground of the 7805.
the output of the 7805 will be connected to the USB pin please refer to the Schematic diagram.
the solar panel and the battery will be connected together so that the solar panel could charge the battery.
there is a switch so that the DC-DC converter wont eat the power even without use.
R1 and R3 is the 75k resistor and the other 2 is the 50k resistor
Step 5: Switch
Step 6: Test
You could also plug USB electric fan and so on as long as it is USB powered.
Making this as an Emergency light could be possible as long as you have a USB Lamp or LED.
after plugging a device you should hear a noise coming from your dc-dc converter.
If you will be making this project i recommend you to place a Voltage level meter so that you know when to charge it and not to use it.
Making this portable and to just make a charging station for this portable charger it would be faster especially if you use a big Solar panel providing high Current.
Don't forget to turn the charger OFF when not in use or you just wasted your charged batteries.
What makes this project expensive is the solar panel and the Battery pack.
Thank you for reading this Instructable.