Instant Cell Phone Charging Cable To USB Port

I lost the wallwart charger for my Motorola V188 cellphone.
So I made a USB->cellphonepower cable and now I charge my phone from my computer's USB port.

This is all a bit ironic, because the phone already has a USB port on it, but is only for data.
It can't charge the phone due to evil suits needing to sell overpriced wallwarts.

WARNING: you probably want to put a fuse in series with the +5V wire and be somewhat careful so you don't fry your computer or cellphone if you accidentally short something.

Step 1: Wire It Together

I happened to have a dead cigarette-lighter-charger with the right power connector on it. I cut that wire and stripped the wire ends.
I cut a USB cable in half and stripped the red and black wires out of that. They are thicker than the others. Black is ground, Red is +5 volts.

I connected red to red and "other" to black. Be somewhat careful, you don't want to toast your computer. I covered my bare wires with packing tape. I didn't have any solder handy.

I plugged my phone in and it charges just fine.
I've been using this setup for a couple of weeks now.

The original charger supplied 6 volts to the phone. Only. The battery management circuitry is all built into the phone.
The battery in the phone is only 3.2 volts, so I figured 5 volts from a USB port would work.

It works fine. Eventually I'll solder and clean up the wiring like this.

Comments

[dlemke]

I'm not an expert, but I know on car type batteries, you need to have a higher voltage to be able to charge the battery. You can't be putting out 12 volts and expect the 12 volt battery to charge. An automotive type alternator's regulator, puts out 13.8 to 16.something, and may vary with models, but you get the idea that a battery charger needs to put out more voltage to be able to charge the battery.

In this instructable, he does mention that the phone he is using has it's own charging monitor included in the phone, where other models may not and is the reason they don't work with this instructable. Just a guess on my part. This is a cool cable to make for many low voltage powered portables, etc... Thanks, I enjoyed it.

PS I do a lot of scrapping of computer junk and end up playing with the parts. I have even put together a box of parts that my wife took to her class for the kids to goof around with, using a 9 volt battery to keep it safe. Her kids are high school aged and the parts I have included are motors, fans, LEDs of all kinds still on the boards, display screens, (best came from an old muti-line phone PCBs), relays, solenoids. I have also included many magnets, including the super strong ones you get from old hard drives. It is surprising how much attention this old junk gets and keeps their brains engaged, since her class is made up of troubled youths. More surprising is the girls seem to like it more than the boys.

PPS: Now that I have found this site, I find that I waste more time here and have to hurry and get my work done! Another distraction that beats playing Mahjong.....

[ImageMaker]

Any phone with a lithium-ion battery (which is all of them made in at least the last four or five years) has the charge control and monitoring circuitry inside the phone -- this is an absolute requirement for charging lithium cells, as they can catch fire or even explode if overcharged. As a result, anything that feeds your phone enough volts to activate the charging circuitry will work (5 V will certainly do the job; most will work on 4.5, like 3 AA cells).

[uberdum05]

if you short-circuited the 5v and ground wires, your computer would probably just shut down because the computers have resettable fuses to protect the USB ports and other ports :)

[Bus213]

Same problem as pvraj123. I have a nokia with battery BL-5B 3.7V, why it does not work? I have tried to make the solar charger, but I had the same problem. Any suggestion?

[pvraj123]

hey buddy...i own a nokia 6630 & tried the exact same steps that you did (cabling et al).But when i connect the cable to my phone (other end to computer's USB port), i get a message on my cell which says 'not charging'.This means that the cellphone recognises the power from the USB port but is not charging the battery (BL-5C,3.7 V,lITHIUM ION).What do you think could be the reason for my phone not charging?

[nevlana]

nokia charger plug has so many links, i had tried that long time ago, you try to give power other cables

[Metaferia]

Hi, i have one question, The USB gives 5v, can the cell phone automatically adjust it ? or it will blow? thx

[GorillazMiko]

Nice job, looks very easy, great pictures by the way. Do you think you can make something reversed of this, like to charge your iPod or something? That would be great!

[The magical duct tape kid]

Dude just do the same thing with an Ipod USB Cable. It works like a charm, I'm not joking.

[Punkguyta]

That's an awesome idea, he should totally make a usb cable to charge his ipod instead of using..oh wait.

[Derin]

lol(i really did lol)

[Punkguyta]

Pretty sweet, I got a noma handheld charger thing that uses 4 rechargable AA's that works pretty decently, however it just doesn't beat it, the only car charger I have for one of my cell's still works so I don't wanna cut it. Btw Tim, I'd change your title to "Motorola XXX Usb Charger" or the such because I'm betting there's probably 200 other instructables with similar titles.