thanks to everyone’s great feedback, i’ve now got a usb battery that’s much more efficient and capable of delivering more current to a portable device. like i promised, i put together a slick little case to finish this hack off right. read on for some tips on building your own.
quick improvement
as mentioned by several readers, you’ll want to use a 5 volt regulator ic instead of the resistor/zener-diode combo i discussed previously. you’ll be able to charge your device faster while it is running and it’s much more efficient, which will give your 9 volt a longer battery life.
the best part is that it’s easier and cheaper to do it this way. just grab an lm7805 from your local hacker store and wire it up. connect the positive battery terminal to the 7805 input pin, the positive usb pin to the 7805 output pin, and connect the negative battery terminal and the usb ground pin to the 7805 ground pin.
which is which? if you hold the 7805 with the text facing you and the pins downward, the pins from left to right are: input, ground, output. it looks like this:
for the female usb connector, look down into the end of the connector so that it is oriented like so:
pin 1 is the positive (5v) terminal (which goes to the output of the 7805) and pin 4 is ground (which goes to the 7805 ground pin).
easiest way to test
several people were wondering how to tell if you are going to fry your device. here’s the easiest way to test when you are all done wiring:
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cut a standard usb cable in half.
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plug the male end into your usb battery.
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connect the positive and negative ends of your multimeter to the red and black usb wires respectively.
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if it reads something very close to 5v then you are wired correctly.
making a case
i chose to make my case out of polystyrene plastic. you can find this stuff in sheet form at most hobby stores. it’s the same kind of plastic used in your standard plastic model kit and the sheet form lends itself nicely to making flat sided objects
Jon B at post 248, you’r just right, this does not work with iPod Video. This didn’t charge at all with 9V battery nor 12V with the LM7805, so I try to use in the input 12V from a power source, but that didn’t solve the problem. The output is allways 5V, but I think that’s not capable to send the necessary power to charge the iPod Video.
The LM7805 somemtimes got a noisy output, so I’ve also try to use a 222uF capacitor to solve the noisy problem, but that didn’t work.
Any one with ideas?
according to this sight
http://www.iguanalabs.com/7805kit.htm
it is nice to have a 220uf capactitor.
would that be this?
http://www.radioshack.com/product/index.jsp?productId=2103623&cp=2032058.2032230.2032267&pg=3&parentPage=family
and if so, do i have to attach like the pins in a certain order? or on certain pins on the LM7805?
PS>what soldering guns do u guys use?
hi, maybe someone can point me in the right direction as to what im doing wrong here. im trying to use this to give my phone(razr v3) power for when it dies, but for some reason when i plug it in nothing happens. everythings hooked up right, i even hooked up an LED to an old cable and plugged it in and it lights up so i know the other end is getting power. my setup looks like this; battery to voltage regulator, regulator to female usb port, any ideas on what i did wrong?
Hi,
I made this for my HP iPAQ and it seems to work fine but not for my nokia 6610i. does anyone know why? I just get the message ‘STOP: Not Charging’.
Thx in advance,
James
i’ve made 2 already, gave one away (bday present, perfect gift, because his razr dies fast, and it charges via usb.), and sold one at school. for those 2, i used plastic styrine like in the project above.. but I made one today, with one of these: http://www.junkfoodblog.com/uploaded_images/jones-soda-flavor-boosters-782790.jpg
I plan on buying more of these boxes tomorrow. They fit nicely. i’ve already assembled 3 of the chargers to sell, 2 of those are waiting for the Jones soda case! :)
A good schematic for an iPod nano charger can be found at
http://liebtrau.eclub.lv/Electronics/iPodNanoCharger/iPodNanoCharger.htm#top
usb is not just wires, it is a complete protocol spec. when you plug a usb device into a standard usb hub, it is supposed to talk to the hub and tell it how much power it needs. The hub then replies by saying “yes” if it can provide enough. so in the case of my rio mp3 player, when the dumb usb battery does not say anything, the rio just shuts off. Oh well, it was a neat idea anyway. Anyone else having problems like this (device powers up on connection then shuts itself down), you are out of luck.
lol.. You say, you came out under 15$, right?
well, I bought a similar USB charger for 9.99$, and some LEGO for 4.99$ to have some fun too..
how’s that?! :D
#249 are u saying that 5.4v – 5.6v will not kill an ipod?
I made this with the specs and it starts to work on my blackberry but then stop charging if i plug it back in agian it starts to work then stops any suggestions??
can a 3G ipod run on 10volts? want to make a rechargeable batt pack and I have a large supply of rechargeable 6V cells. wire 2 in series and I have 12volts, but if I’m going to use a LM78xx voltage regulator (is it really necessary?) it needs about 2 volts higher on its input vs. the regulated output. I don’t want to wire 3 cells in series to create 18 volts since that will wast e a lot of heat. I’d rather just use 2 cells, creat 12vdc and then regulate that down to about 10volts using a variable regulator. but will the ipod run on 10volts?
I have a car 12V to female USB adapter that outputs 12V on pin 4. Can I solder a LM7805 internally to it and convert it to 5V and power up my iPod Mini (2nd Gen)? Also do I need to worry about heat going from 12V to 5V ?
I hooked up everything as told, but the output is 7.5 volts…need help
heres what I did
http://img235.imageshack.us/img235/6372/usbchargerprototype1a4ow.jpg
Im getting 7v for output, what am I doing wrong?
DO U KNOW HOW I CAN CHARGE ME CELLPHONE WHILE I AM USEING IT AS A MODOM FOR MY LAPTOP????
I AM USEING AN 8100 SERIES SANYO CELLPHONE.
Hey I’m thinking about building one of these and I was wondering if a four pin mini usb cable V+ and ground are in the same location as the five pin type? I want to skip puting a female usb plug and just use a cable with a compatiable plug on it. I want to know if i can charge a five pin device with a four pin plug or will the power pins not match up?
A great little device. I’m planning to make one this weekend!
Ok, I’m not very wise in the ways of electronics (I own a Zune, after all) but why won’t the Zune charge off one of these. I haven’t actually constructed this very design, but I’ve essentially run 5 volts into the Zune’s USB cable and nothing happens. From what I can tell, Zune doesn’t need any drivers to just charge. It just needs to recognize that it’s plugged into a computer. Is it possible to charge this thing with a portable device? They want 35 bucks for just an AC charger, so I’d rather make something myself.
I recomend adding a diode capable of withstanding a back current greater then the voltage produced by the battery you use between the battery positive connect and the regulator. This prevents accidental reverse current which would fry your regulator. I use a 1N4003 which can withstand 200V Peak inverse voltage, far more then the regulator could handle anyway let alone what a 9V could produce.
Hey all. Slightly off topic question. I am getting a guitar with what I assume to be a usb sound card within. makes it possible to connect it to the pc and record with pretty good quality. The guitar also has a headphone out jack, making it possible to listen to your manly licks without bothering anyone else.
the headphone jack only works when attached to a pc.
My question is this. would the aforementioned
powerpack be enough to power the usb sound card to let me use the h-phones without being attached to a pc, and do you think the guitar needs the pc to make the s card work?
I’ve found a regulator with this specs:
76S05
V out: 5 V
I out max 2 A
V in max: 35 V
The regulators linked to here has only 1 A output, so I wonder if this can be used, or will it destroy my mp3 player?
I have bean wondering if we can use this ‘charger’ to power up other thing, like an wifi usb stick? I tried to power an wifi usb stick with 4 AAs rechargeable batteries (only the the 4 AAs), but it wont work properly, I think it can be lack of power.
Hey just a quick couple questions. One do you have to tie pins 2 & 3 to ground as well with the 4th pin. And second when I plug my moto q into it to charge will it show the charging icon on the phone or not. And finally what is the voltage to charge a microsoft zune because it should work since you can charge it with a usb plug on a computer should be able to use that cord just not sure on the voltage.
If I have 5.7v and i want to plug my 3g Ipod Nano. It will burn or ruin it?
need instruction to wire ipod car charger to a usb to download 2g&4g thanks
i have a flash psp but a normal battery. the battery would not charge and it says! charge level 0%, power source-external and battery status – charge complete. please help me
I’m only getting 4.1v from the battery after the current goes through the regulator and my phone doesn’t seem to be charging when i connect it. any ideas?
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