Introduction: 9v USB Charger

Picture of 9v USB Charger

very easy USB 9 volt charger

Step 1: Parts List

Picture of Parts List

L78M05CV  5V 500 Ma voltage regulator
9 volt battery snap
USB connector (female) ,or phone charger plug
of course soldering iron and some solder.
optional - extra wire ,heat shrink ,recharge able 9v battery ,multimeter (for checking if all are working correctly.)
I bought 9v 250 Mah battery for 6$. I think if you build this you'll need recharge able battery. For wire i just use wire from 9v battery snap.

Step 2: SOOO Easy!

Picture of SOOO Easy!

this step will show you how to connect parts correctly.
on usb that 2 middle pins you can just snap off.
voltage regulator's numbers side up.

Step 3: Finally You Can Now Charge Portably.

Picture of Finally You Can Now Charge Portably.

that device can charge anything what charges with 5 volts,only what you need to do is change usb to nokia , or any other  5 volt charing device plug. thank you for viewing this instructable !!! :)


micahnightwolf (author)2017-03-20

Linear regulator is horrible for applications like this. You are way better off using 2 AA batteries and a boost converter. Or if you must use a 9v, use a switch mode regulator. They're huge but less wasteful.

Gomi no Sensei (author)2015-11-30

Most smart phone batteries are 1500-3300mah.

A 9V battery has 50-400mah and at 500mw load has less than 300mah capacity.

You're also losing 30% of that 300mah thru the 7805 as heat.

Just exactly HOW much does this remaining 210mah charge your phone ???

Ref :

hemanpreet.oberoi.79 (author)2014-10-20

this charger works for 5 secs after that it do not charge my phone but after disconnecting it and connecting it again with my phone it works for 5 secs again

That's because 9V batteries die under the +500mah load.

This is a stupid project.

BacemA (author)2015-09-19

the worst circuit ever . first i really think u should use a buck converter circuit (much higher efficiency) ,you can make it your self or buy a premade one . change the potentiometer (resistor) with a screwdriver in the circuit so it output 5v )

as of why the circuit is bad is because the linear regulator has to dissipate 2 w without any sort of heatsink (9-5=4 volt , 4*0.5A , 2W ) the regulator can not dissipate 2 w , it have thermal limit that stop output when reach 150 degrée (so it doesn't blow ) it will literally output a hashed voltage and u phone will not like it

sipek (author)2015-04-17

Voltage regulaters are the worse for circuits that involve batteries. You are literally wasting the most of the energy on heat

OwenH2 made it! (author)2014-12-13

Is this safe for your phone? Like day to day use? Or is it just for an emergency?

majenko (author)2014-11-11

I'm sorry, but that really is the worst possible design for a phone charger imaginable.

1. Where are the capacitors for the voltage regulator?

2. Why are there no D+ and D- resistors to enable charge mode?

3. How do you expect to charge a (typically 1500mAh) phone battery from a 500mAh 9V battery? (150mAh if you use a rechargeable one...!).

With modification it might allow you to use a brand new Alkaline battery to charge the phone enough to make an emergency call, as long as you don't want to say much.

PatrickS2 (author)2014-08-26

Would you be able to use this with a 9v power adapter? I need USB power from my pedal board. I have extra 9v cables, and I need to power a usb device on the board without running any extra power supplies. Could I use this adapter from the 9v power supply?

tim.leitzke.9 (author)2014-08-20

can I use such things like this (5v regulator) for the newer apple lightning connectors?mor do I need a different regulator?

SurajP (author)2014-08-14

using this circuit output raises from 5v to 6.6v after 30 min (input voltage 7.5v from adapter)

kushalverma (author)2011-07-11

if we supply 12v instead of 9v then will it work????
can we charge more than 2-3 mobile phones at a one time???????
plz rply

lorddavis6 (author)kushalverma2011-07-11

12v will work fine. If you add more usb conectors (red with red and black with black wire) on output conections , then you could charge multiple devices at the same time.

speart1 (author)lorddavis62014-05-08

Be careful supplying much more than the intended voltage coming out of the voltage regulator. Cheaper 5v regulators have a drop-off voltage of about 2v, meaning you need to power it with at least 7v for it to deliver a proper 5v, but using more input voltage will result in significantly more heat coming from your regulator in which you really need a heatsink or you will most certainly melt the back of that plastic casing for your batteries!!! I have burnt myself more than once this way :)

kmagic4 (author)2010-09-05

sorry but your circuit is wrong.... the way you have it drawn the gnd on the regulator is going to the posotive side of the battery and that doesnt make any sense...gnd should go to your usb and negative side of battery....the output should go to the other side of your usb and you in should go to the posotive side of your 9v.. and the switch can be thrown in anywhere.... correct me if im wrong but i usually am not..LOL!

lorddavis6 (author)kmagic42010-09-10

i"ve connected this charger exactly like it is showed schematic and in real life model too. it is working very well,but regulator may get hot! :( regulator is that side up what is showed in picture at (step 1).sorry if you can,t understand some words,i"m not from USA or UK.

dmegill (author)lorddavis62014-03-31

Just take a washer and bolt it to the regulator for a plain and simple heat sink. Preferably aluminum. But other than that you may be able to find small heat sinks in old computers

lorddavis6 (author)kmagic42010-09-10

and thanx for correcting even ,if you are wrong ,but it is nice if someone helps!

sheldon5992 (author)2014-02-18

Now can you use this to charge the 9v batty also? and if you did what would keep the battery from over charging and exploding? Does any one know how to make a 9v battery charging circuit?

Timothy982017 (author)2013-11-05

please help me i did a project like this but with a added led and i hooked up everything right and everything works but when i plug my phine into the usb the led goes off and my phone doesnt charge

Vanila (author)2011-01-07

Will this word with the new Ipod Touch 4?

Data643 (author)Vanila2011-01-24

No, iPods & iPhones need a special circuit. I've tried this schematic and it did not work with my iPod Touch

You will need to make the circuit from here:

It uses a few resistors to give voltage to the two middle pins

Xixfas (author)Data6432013-08-23

yes someone finally gets it!

TechyGeeky (author)Data6432011-02-20

Thanks for the link! I'm going to go to the local electronics shop to buy the components now.

lorddavis6 (author)Data6432011-01-27

thank you ! I Don,t own any apple product

Themaxim (author)2012-12-23

How many volt does a ipad 2 need for to charge?

Xixfas (author)Themaxim2013-08-23

you need a resistor on the info wires for ios devices (author)Themaxim2013-01-29

5v and about 1000mah +

lorddavis6 (author)Themaxim2012-12-27

It should be written on the charger that it came with or you could always search it on Google.

sraul1 (author)2013-05-13

Middle two wires are for Data + & Data - ...
ignore them .. just use two extreme ends wires ... those carries ~5V current ! ...

Xixfas (author)sraul12013-08-23

you need a resistor on the info wires for ios devices

devashishkumar (author)2013-07-07

i made this ..but my phone is charging with discharging means if puted for one hour its only charge 10% after that the percentage is not increased but my phone is shows it is charging ..after that if restarted my phone it becomes 0 % nothing charged what can i do please help me:(

Cristu (author)2013-05-27


Very nice instructable, doable in less than 15 minutes even for a beginner in soldering like me. I've made it, only that I didn't use the switch and everything is more compact because I'd like to put it in resin or something to make it more solid so I could use it without worrying that the wires will snap off. Also instead of the female usb port I've used a male micro usb to plug it directly in my phone.

Keep it up!

NoVet54 (author)2013-05-07

My female usb port comes black, red, green, and white wires. What should I do?

Ibenos (author)2013-04-02

How many volts is the voltige regulator???

ebaratita (author)2011-12-10

i think you need 3 capasitors for this one

lorddavis6 (author)ebaratita2012-05-17

This is very basic charger.I tried to make it from as less parts as I could. Maybe you should make your own version of this ckarger

fancysaukrel (author)2011-10-21

Hello,im just wondering if you know of any electronics that i can get a female usb connctor sorry im cheap and dont want to have to buy one

lorddavis6 (author)fancysaukrel2012-05-17

You could get a female usb connector from a cheap usb extender cord

lorddavis6 (author)fancysaukrel2011-10-24

You can get USB (normal kind) extender and cut it of.
You can buy USB female connector separetly from makershed or godaddy ,or some websites like that.
BTW Sorry for my bad english skills. :)

lorddavis6 (author)2010-06-29

sorry for so little image in 2nd step.

martenp (author)lorddavis62011-08-14

It is correct, the gnd comes form the batterys negative and goes to regulators centre, where its supposed to go, then it goes to the usbs negative :) everything is correct

seben (author)2011-07-23

will this work for charging my psp 3001, and do i need a female usb from a old computer or does it half to be from a wire.

dfalk (author)2011-07-08

Hi nice!

Can u link where I can buy L78M05CV 5V 500 Ma voltage regulator

lorddavis6 (author)dfalk2011-07-11

You can find it at radioshack or bought mine at local radio electronics store.

dfalk (author)2011-07-09

Does it works to other phones?

lorddavis6 (author)dfalk2011-07-11

If they charge with usb , then yes.

Timofte Andrei (author)2011-01-16

i've done this and it's working like a dream :D i've tried to charge a nokia 2600 classic with this and works just fine :) now i need to find a small box :) oh and...this thing is pretty cheap! if you search on web you can find emergency chargers for almost 40$ :P sorry for my english ;) greetings from Romania ;)

thanx! :)

Dread_Neck (author)2010-11-06

How did you get the casing off of the female adapter?

About This Instructable




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