Wednesday, November 4, 2009

Make a USB charger from 9Volt battry

Make a 9V battry USB charger:-

Battery powered USB chargers are pretty cheap at Amazon and other places, but as with everything else it's always more fun to make your own. The basic concept of a USB charger is actually pretty simple, and you don't really need more than a couple of very cheap components to make one yourself.

Concept and parts

The concept is simple; USB power is 5V. What else is 5V? No batteries. Sometimes you find chargers that use 4 AA/AAA batteries as this is 4.8V (if rechargable, 1.2V x 4) or 6V (if disposable, 1.5V x 4) but to have a charger that produces exactly 5V you need a voltage regulator. Such a regulator is the 7805 model you can get at Radio Shack for $1.59. This will take a voltage between 7.5V and 20V (according to Google research) and turn it into a steady 5V. Turn this into a charger, and there you go.

On top of this you also need a suitable power source (9V battery in my case), some wires (and a battery connector in my case) and a connector to connect to the device you want to charge- like a female USB port you can salvage off old computers etc.

The build

The assembly process is so simple it's almost redundant to describe it. Wire the setup like in the diagram and solder it stuck and you're basically done. With a 7805 regulator with a TO-220 type case like the one linked to above, the diagram shows the heatsink pointing away from you. The positive lead from the battery goes to the regulators left leg, and the regulated 5V goes from its right leg to the far left pin of the female USB port as it is when you're holding the female port pointing towards you with the pins pointing down from the plastic part they're stuck to. The ground wire goes from the battery to the middle leg of the regulator and then continues to the far right pin of the female USB port. Just look at the diagram and you'll see what I mean.

You might want to use a hot glue gun or some sort of casing to make it stick together. I wanted a very small easy to carry solution so I made it all into a single small adapter, but you might want to use multiple batteries (5x D batteries in a series would give you a lot of juice, for example) or another design for yours.

Not all devices will be able to charge from such a setup due to limitations in place by the manufacturers. Since you're making this from scratch, you might actually be able to make on that works if you know the criteria for you device to charge (such as having the two middle USB pins connected).


how many hours does the 9v battery take to fully charge a high powered smartphone.

How long does the 9v battery last?
and also how long does it take to charge an iphone?

how much resistance does the 7805 have?

It is really nice for me to see you and your great hardwork again.Every piece of your work look excellent.Looking forward to learing more from you!

It really is simple to build. I should check out the cost of a USB charger at my local store. Maybe I can give them a run for their money ;-)

It's important to save on computer supplies when we can. Sometimes the things we think are necessary aren't. Using coupons and discounts helps but making some of our own stuff works well sometimes too.

I used the exact same components and same connections yet instead of charging my phone gets discharged...... What to do........

please check the supported voltage level of your phone at which it charges the phone...

can i use Nokia pin instead of female usb??

"""" Anonymous says:
May 5, 2014 at 11:00 AM Reply
can i use Nokia pin instead of female usb?? """"


How many amps will provide such setup?

I appreciate your work. I’ve been looking for quite some time such an useful resource and I’m very glad I found it. Keep up the good work! magnetic charging cable

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