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9V battery charger for phone

This workshop will show you how to get 5 V for USB from a 9 V battery and use it to charge your mobile phone.
In the photo, the assembled circuit is in work, but this is not the final option, since I will also make a case for it at the end.
So, let's get down to manufacturing.


9V battery charger for phone

The picture shows the components necessary for assembling the charger, including one empty case from the old battery, in which the device will be built.
Components and materials:
  • Old battery for the case.
  • USB port
  • Integrated circuit regulator 7805.
  • One green LED.
  • 220R Resistors - 3 pcs.
  • Solder.
  • Wires.


9V battery charger for phone

The diagram shows the pinout of the 7805 controller, the USB connector, and the actual circuit of a simple converter.

Charger assembly according to the scheme

9V battery charger for phone

After disassembling the old battery, parts can be soldered to the base with the connector. Everything gathers in five minutes, and I think that nothing needs explanation, except for the resistors connected in the middle USB contacts - Data + and Data-. And they are needed so that the cell phone itself understands that it is connected to a charger, and not to a computer for data transfer.
The circuit does not need settings and starts working immediately.
The LED indicates the presence of a flow of charging current. If it does not light, it means the battery is completely discharged, or the phone is fully charged.

Transformer Ready

9V battery charger for phone

The picture shows the finished device in the case. It is convenient to carry the mini-charger with you in your pocket, since it is very small, and together with the battery.
come back
Comments (9)
  1. Victor
    #1 Victor Guests February 14, 2018 09:15
    Let the battery cost about 100r. This is the price of one charge. It’s easier to buy a lithium-ion 18650. They are becoming more affordable at a price. I didn’t understand by the LED, more current passes through it than its working current.
  2. Punch9
    #2 Punch9 Guests February 16, 2018 09:58
    But nothing that the charge current of this device will be 20mA? That is how much the LED will let through itself.
  3. Alesay
    #3 Alesay Guests February 16, 2018 18:12
    How much power do you want to squeeze out of this battery?
  4. Did
    #4 Did Guests February 18, 2018 07:18
    The author is clearly inadequate. Do not try to sculpt it. To charge the phone once, you need about 15 krona batteries. And 40 hours of time to charge. Since the current in the crown is very small, but I generally keep quiet about the ampere clock ..
  5. Guest Oleg
    #5 Guest Oleg Guests March 14, 2018 2:00 p.m.
    Really some kind of canoe. A thing that brings us back to the Stone Age. It would be better if charging from a WIFI signal was shown.
  6. Guest Oleg
    #6 Guest Oleg Guests March 14, 2018 2:05 p.m.
    Better circuit for 12 volts. So at least get a charge from the car. Although the finished devices on sale are full. What is the topic?
  7. Audio man
    #7 Audio man Guests March 12, 2019 01:41
    The circuit will charge normally if you do not use those resistors that are connected to the 2 and 3 pins of the USB plug. From the crown, the charging current is 480mA. The author is not inadequate; the scheme is simply incomplete.
  8. Alexey
    #8 Alexey Guests April 10, 2019 10:27 p.m.
    I have a 4000mA phone and how many batteries do I need ??? there isn’t so much in the store, why two resistors on the bus date ??? the phone and without them will understand that on charging only a leak, and everything through the LED is generally an epicrisis
  9. Guest Vitaliy
    #9 Guest Vitaliy Guests 30 June 2019 01:01
    I understood the idea - an analogy with a transformer: a high voltage at a low current is converted to a low voltage at a high current. Let's say. Just keep in mind that Krenka 7805 has a maximum output current of 0.5 A. Thus, only key phones can be charged.

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