DIY - Pocket Sized USB Mobile Charger

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Introduction: DIY - Pocket Sized USB Mobile Charger

About: Hello Guys, I am techgenie, an Electronics hobbyists, tech tinker and developer. I dedicate my free time in designing and making various creative and innovative projects, RC toys, Incredible Gadgets, Awesome...

Mobile Phones, are an essential commodity. There are often times when we find ourselves in situations when the battery is about to go off, leaving us in emergency. People generally keep mobile powerbanks or car chargers with themselves but they are also only useful upto an extent.

In this instructable, I decided to make a mini USB mobile charger that can be used to charge a cell phone just with a 9v battery. So next time you find yourself in a tough situation, just buy a 9v battery at the corner shop and you will have enough power to handle the emergency situations.

Note: This charger will only work for android devices. It is recommended to use a high current 9v battery (like Duracell or energiser), a normal cheap chinese battery will not provide enough backup.

Step 1: Watch the Video

A video is a wonderful tool that provides deep insight into the understanding of the procedure and also makes it easy to follow the steps.

Step 2: Order Parts

Ebay.com

  1. 7805 Voltage regulator - https://rover.ebay.com/rover/1/711-53200-19255-0/...
  2. Female USB Port - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
  3. 100 ohm resistor - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
  4. LED - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
  5. 9v Battery - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
  6. Soldering Iron - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
  7. Hot Glue Gun - https://rover.ebay.com/rover/1/711-53200-19255-0/1...

Amazon.com

  1. 7805 Voltage regulator - http://amzn.to/2q8oRU8
  2. Female USB Port - http://amzn.to/2q8hOej
  3. 100 ohm resistor - http://amzn.to/2seVmBm
  4. LED - http://amzn.to/2xBS2a5
  5. 9v Battery - http://amzn.to/2txOMJL
  6. Soldering Iron - http://amzn.to/2r3IX6g
  7. Hot Glue Gun - http://amzn.to/2vQEINI

Amazon.in

  1. 7805 Voltage regulator - http://amzn.to/2qLukTZ
  2. Female USB Port - http://amzn.to/2rH34E6
  3. 100 ohm resistor - http://amzn.to/2sB1W4m
  4. LED - http://amzn.to/2yhvKtT
  5. 9v Battery - http://amzn.to/2ulSibD
  6. Soldering Iron - http://amzn.to/2qC47qG
  7. Hot Glue Gun - http://amzn.to/2rjNE9r

From Home & Local Store: Two bottle caps, old 9v battery, spray paint and connecting wires.

Step 3: Let's Begin

  1. Take two plastic bottle caps.
  2. Cut a slit at the center of the cap such that a female USB port can be inserted in it.
  3. Make a hole at the center of the other bottle cap.
  4. Using a spray paint, color the bottle caps as per the desired choice.
  5. Solder wires to the Pin 1(Vcc) and Pin 4(Gnd) of the USB port.
  6. Insert the USB port in the bottle cap as shown in the image above and secure it with hot glue.
  7. Take a 3mm LED and solder a 100 ohm resistor to '+ve' LED leg.

Step 4: Add the Components

  1. Take a 7805 voltage regulator IC.Solder the Vcc wire from the USB port to the output terminal (Pin 3) of the 7805 IC.
  2. Similarly, solder the Gnd wire to the Gnd terminal (Pin 2) of 7805 IC.
  3. Make a hole on the side of a bottle cap.
  4. Insert the LED in the hole and secure it with the Hot Glue.
  5. It is an indicator LED that will indicate the power to the circuit.
  6. Connect the '-ve' LED leg to the Gnd terminal of 7805 IC.
  7. Connect the other leg to the input terminal (Pin 1) of 7805 IC.
  8. Take a 9v battery connector clip and paste it over the surface of the second bottle cap. Note: You can easily extract a connector from an old 9v battery by watching this Video.
  9. Connect the '+ve' battery terminal to the input terminal (Pin 1) of 7805 IC.
  10. Connect the -ve battery terminal to the Gnd terminal of the 7805 IC.
  11. Make sure to refer to the schematic diagram attached above.
  12. After verifying all the connections, seal both the bottle caps together using hot glue.

Step 5: Testing the Charger

Our mini Portable USB charger is now ready. Connect a 9v battery to the charger. Plug a USB cable in the USB port and connect it to the mobile phone.

The mobile device begins to charge and the backup will depend on the quality of 9v battery used. A good quality battery can charge a 3000mAh cell phone battery upto 15-20%.

Note: This device can also be used to charge the cell phone using any wall adapter upto 12v in case of emergency situations. Because of 7805 voltage regulator it will provide regulated 5v to the cell phone. However, you can also add capacitors to the input-Gnd and output-Gnd terminals of 7805 to get smooth voltage output.

So friends, this here concludes the instructable, stay tuned and SUBSCRIBE to receive regular updates. In case you might have missed, have a look at the video and see how i made this mini USB charger at home.

Thanks for your Support ...!!

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    3 Discussions

    Using a 9V battery to charge a cell phone is a great way to spend a fortune on 9V batteries and still not have any charge on your phone. 9V batteries have a very low amount of amperage and won't charge a phone more than 1-2%. This is why everyone is using those $5 USB power banks. They will give you half a charge or better (for the small ones) and are rechargeable. And cheap. And rechargeable. Using a 9V battery "works" in the same way that swimming across the Atlantic "works", but anyone with common sense would just take a boat.

    2 replies

    Plus it is somewhat inefficient using a linear regulator which turns (9 - 5)V * I into heat. Better to use a rechargeable battery (even recycled from old laptops) +some cheap boost regulator here.

    Exactly. I hate always being "that guy" who says negative things about DIY chargers, but there are a lot of projects that "work" but you'd never actually want to use for charging.