USB Wall, Car, and Battery Charger




Introduction: USB Wall, Car, and Battery Charger

About: from nothing something new

Has your iPod battery ever run out when you really needed it?

This simple instructable will show you how to make a wall charger that can charge / operate any USB device, including iPhones and iPods.

Most DIY chargers can not charge iPods and iPhones. This one can, however!

This charger takes input from both a 9v battery and a size N DC Coaxial plug.
A wall charger or car charger with the right voltage and amperage can be modified to have a size N DC Coax plug with a cable coming out of it.

Most of the pictures of the charger itself are on the last page (Step 7).

Step 1: Materials

You need the following items:

5V regulator and SMALL Heatsink: I used Radio Shack part:

Resistors: 22 Kohm (1), 27 Kohm (2), 39 Kohm (1).
I used Radio Shack part:

DPDT Toggle Switch: This will be used to switch between the battery and the DC Coax Jack. 

USB Extension Cable: Any cable with a type A Female USB port will work.

AC / DC Wall Transformer: Try to get one with <10 volts and equal to or less than 1.5 amps. The regulator will overheat and / or blow if you put more than 1.5 amps into it.

Cigarette Lighter Car Adapter: 12V dc

Size N DC Power Plug (2): With wires attatched.

Size N DC Power Jack (1): Panel Mount with solder leads.

Prototyping Board: I used Radio Shack Part:

Project Box: Whatever kind you need to fit the components inside

Wire: I used a mix of 22 gauge solid and stranded wire.

Heat Shrink Tubing: An assortment of sizes would help.

9V battery and 9V Battery Clip

Cable Stress Relief Joint That Fits The USB Cable: I cannot stress (No pun intended) how important this is. If this fails then the USB cable solder joints can be damaged


Soldering Iron with Solder

Wire Cutters


Third Hand (Optional, but would be very useful)

Step 2: Step 1: Understand the Layout and Circuit

The following circuit diagram is from the Jameco Website. The 9V Battery and the DC coax plug will both be connected to the DPDT switch, which is ultimately connected to the PCB.

To find the pins of the USB Cable, cut and strip the end with the female port, leaving about 2 inches of wire on the end. The different colored cables are labeled as follows:

Red: + 5V
Black: -
White: Data +
Green: Data -

Step 3: Step 3: Solder the Components

Solder all of the components onto the board using the circuit diagram in step 1.

My circuit after soldering is shown in the picture. Unfortunately, I put the circuit board in the case before I took the picture.

Step 4: Mount the PCB in the Case

Try to get a large project box. It will be easier to install all of your components inside it.

Use screws to mount the circuit board.

My project box had PCB screw mounts already on it, but I had to cut them off, move them, and glue them back down.

Also, cut out a notch that fits the stress relief joint, glue it in, and put the cable in.

Step 5: Modify the Transformers

To open the chargers, you can use a variety of methods. I used all three of the following:

1. Find the crack in the transformer and pound at with a thin screwdriver and a hammer untill it cracks along the line.

2. Slowly cut the crack in the transformer with a utility knife.

3. Find the crack in the transformer and cut it open with a hacksaw

Find the + and - terminals of the transformer and unsolder the wires that were there. Resolder the wires from your DC Male plug onto the same points. Make sure you have the polarity correct!

Test the polarity with a multimeter, and if all is well epoxy the case of your transformers shut.

You can skip this step if your transformer already has the size N DC plug on it.

Step 6: Mount and Solder the Switch and DC Jack.

Mount the DPDT switch and the DC coax plug in a reasonable location. Then solder them to the circuit board using the schematic below.

Step 7: Finish

Screw on the lid and test it out. If it works, Hurray, if not, check all of your solder connections and the schematic.

Another important factor to consider when making this is to make sure that the transformer has less than 25 volts and less than 1.5 amps.

I added some stickers for fun. It'll get some funny looks on the bus or the plane.

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    11 years ago on Introduction

    Your charger may very well work fine, but your schematic does not reflect a correct switch for switching power sources. Don't read into raw text - you don't seem able to do it well.


    Reply 11 years ago on Introduction

    Well, I'm not the best with electronics yet.


    11 years ago on Introduction

    Your schematic is missing the N connector and the other pole of the DPDT you show with the switch above with. This is a good instructable, but needs the simple change mentioned above for clarity!


    Reply 11 years ago on Introduction

    Sorry,it might be a single throw, but I'm not sure. The switch only has two positions. Hope that helps.


    Reply 11 years ago on Introduction

    The schematic is incorrect. The left leg of the 7805 regulator is IN. That is where the bat of the switch is located. The other end of the SPST switch should be to your N jack positive to use it to connect to an AC adapter instead of chewing up the 9V. Connect all grounds - don't use the switch! That way, your switch works to switch between power sources. Also, the parts list needs to be changed to reflect the change from DPDT to SPST - you don't switch the grounds. Ground is permanently connected. I guess the picture showing the switch can just go away if you correct the schematic as I suggest.


    Reply 11 years ago on Introduction

    My charger works perfectly fine and I used the schematics in this instructable. My charger does not "chew up" the 9v battery at all since the leads from it are not leading to the circuit board unless the switch is in the battery position.