How To Make Your Own USB Car Charger For Any iPod Or Other Devices That Charge Via USB

Picture of How To Make Your Own USB Car Charger For Any iPod Or Other Devices That Charge Via USB
Create a USB car charger for any iPod or other Device that Charges Via USB by splicing together a car adapter that outputs 5v and USB Female plug. The most important part of this project is to make sure that the output your chosen car adapter is between 4.75v and 5.25v otherwise you risk damaging your device. Please verify voltage with a voltmeter.

Step 1: Introduction

Picture of Introduction
Note: I have tested this only on an iPod Nano, but I would imagine that It would work for any iPod that charges via USB, or any device that charges over USB that uses a 5v source for charge.

The basic idea here is to charge my Nano via USB while in the car. The total project cost for me was Free-99. I had all the spare wiring and cables because I never throw anything electronic away. I did however build another one for a shade under $8 bucks. I mean thats not terrible for a car charger for your iPod and other USB chargeable devices. Plus its fun to DIY.

Typically, your USB port provides 5v of power through a single wire in a 4 pin USB cable. The normal operating voltage for most USB devices is between 4.75 V and 5.25 V. Ok great we understand that, but now how to get 5v from the 12 volt source (your car)? I stumbled upon this idea by accident, literally, I tripped over my wall charger for my Nextel-Motorola i870 and noticed that the adapter has an output of 5v to charge the phone. So, I went outside to my car to check the output voltage of my car charger, it was unmarked, so off to the Wal-Mart that is across the street I went to pick up a multi-tester. Upon testing the voltage output of my car charger I was astonished to see that sure enough the output was 5.15v well within the range to charge the iPod.

Read that last part again, I verified the voltage on a voltmeter. I also tested several other car adapters I had laying around, and the output voltages varied greatly, from 3v to 14v. So unless you are positive of the output voltage dont just splice away expect to get the right voltage to your iPod. (on a side note I also constructed a Firewire wire alternative from the aforementioned 14v car charger, and a tutorial for this one is coming soon). After verifying that the voltage was within normal USB operating range I used a USB extension cable to get a female USB plug. The next steps follow logically, splice USB female end to car adapter wires, seal, test voltage, go plug in. Direction and some pics follow.
Rosezdea1 year ago

This article is 7years ago.

Now, I think one new product can solve the problem.

There are already dual ports USB car chargers. Here I suggest one on the web: http://www.usbcaradapter.com/products/dual-usb-car-charger.html

You can see, there are already two ports output, it is enough for the normal use on the car.

And there are also 3 ports or even 4 ports output car chargers if you would like to search on google.

Anyway, thank you for the share! It is good article in 7 years!

thedra7 years ago
What are the blue(green?) and white wires? Just ignore them? Thanks
These are your data lines. Sometimes they must be biased or terminated in order for the device to be recognized. This is especially true for the iPod.
I highly recommend checking out this article from AdaFruit. It goes over the design of a USB charger and explains what different voltages on the data lines mean. http://www.ladyada.net/make/mintyboost/icharge.html
murph38_99 (author) 9 years ago
Since making this I also realised that 2 other things could be done in this manner. First, you could make an extra wall charger by using the motorola wall adapter (Model:PSM4680A) since it also has a 5v output. Secondly, you can use the unused male end of the usb extension cable spliced together with the part that plugs (the part you clipped off) into the phone, and still use the charger as a phone charger as well, simply plug the male end back into the female USB end and presto, you still have a functioning car adapter for your phone.
could said charger use 4 aa batteries... i know that equals 6 volts but then you could slap on a capacitor or resistor to make it 5v?...
(Yes, I know I am 6 years late to the party. It's for future reference)
USB chargers should output between 4.75 and 5.25 volts, and for full charging efficiency 1900 mA (Any set of batteries will provide more than that. Over-amperage won't damage your devices, as they will just pull what they need). Low power USB devices should be able to work with as little as 4.4 V, and all devices should be able to signal, if not work.
Now, a standard disposable battery is rated as outputting 1.5 V, and will at most of it's useful life, but when they are brand new they use to output as much as 1.6 and 1.7 volts, and they go down as they discharge. Most devices are aware of this and will work at 1.2 volts and up. Rechargeable batteries output at less voltage (Fully charged at 1.4 or less and for most of its use before recharging at 1.3 - 1.2), but have a less step voltage diminution graph.
Down to the math:
Brand new alkaline outputting 1.7:
3x1.7=5.1 (OK)
Brand new alkaline outputting 1.6:
3x1.6=4.8 (OK)
Less batteries you are too low, more you are dangerously high.
Used alkaline (1.5):
3x1.5=4.5 Low, but usable (-0.25v)
4x1.5=6, way too high (0.75v)
fully charged rechargeable (1.4):
3x1.4=4.2, too low (-0.55)
4x1.4=5.6, too high (0.35v)
Somewhat used rechargeable:
3x1.3=3.9 too low (-0.85v)
4x1.3=5.2 (OK)
Used rechargeable (1.2):
3x1.2=3.6 way too low (-1.15v)
4x1,2=4.8 (OK)

Most devices will have higher tolerances than the USB standard requires, but the question is ¿Do you feel like risking? In any case, under-voltage is much less likely to do damage than over-voltage.
It would be much easier to just use a zener diode and a resister in parallel with the diode on the + end, as a voltage regulator
Yes, I think it is much possible. Probably won't get a lot of time, but will work great for an emergency charger for your usb phone.
Check this out:
for details on how to calculate the amount of resistance needed.
nodoubtman3 years ago
Your stuff doesnt work at all!!!!
baldmosher3 years ago
This post is relative specifically to HTC phones and I assume similar problems affect each specific device.

I've been researching this for a while as the HTC Desire is quite choosy about pulling >500mA (indicated on the phone as "AC Charging" rather than "USB Charging").

This whole thread goes into very good detail but this post in particular covers the issue nicely: http://androidforums.com/htc-desire/75062-charging-usb-ac-differences-4.html#post2980915

Adding resistors (max 200ohm) to the data pins will cause the Desire to assume it's connected to USB computer and therefore the phone will not try to draw more than 500mA. Indeed, it seems using a long cable (2m) may provide enough resistance to fool the Desire. So ideally, you want to short the data pins at the microUSB end. That's easier said than done, so you may have to experiment with a few different cables. YMMV and it seems everyone's does.

The basic points are that to get more than 500mA into your Desire, you need a car adapter capable of outputting enough current, and a good quality cable with the data pins shorted.

I would assume this applies to all HTC phones and perhaps many other devices.
chevelle3506 years ago
This is great and is what I made this weekend (On my own, before I saw this.) The differences were that the first time I did not connect the data lines in the USB cable. This caused my Blackberry to not charge. I changed the data lines to ground. This lets the device charge for about 5 seconds, then it quits. Is there something else that needs to be done with the data lines? This same unit was used with a e200 series sansa. The unit did not charge with the data lines disconnected. I haven't tested the unit with the data lines to ground yet. I am able to use other USB powered devices with the cord. This Belkin unit is great for this job as it puts out good voltage -- it did a great job of charging my Motorola cell phone.
yes u have to connect ur data lines with a certain connection not simply grounded to start charging i've tried the above connection for my iPod classic and it didn't work i don't know the exact connection that u need for ur phone but i'm sure that u have to connect the 2 data lines correctly
For the HTC Desire, simply fusing the data wires tells the device it's plugged into AC power, so it draws more current than the 512mA USB maximum. I imagine it's specific to each device though.
dalmond14 years ago
Sus out this Video on Iphone charging very informitive
comicalmuse4 years ago
Not to put a damper on the build... but just wanted to share the option that you can buy a pre-built, clean, ready-to-go cig-USB adaptor on ebay for $2.38 with shipping... (or about $4 from US seller). Nice DIY, but just wanted to throw the option out there.
murph38_99 (author)  comicalmuse4 years ago
Thanks for your timely, relevant reply.
grimrencher4 years ago
great instructable, once i find the appropriate charger i'll give this a shot. i was planning on putting the circuitry in a small enclosure, hard wiring it to my accessory power, then putting a switch to turn it on and off when i need it. i'm pretty sure just putting a switch into the circuit would burn out the circuit (as this has happened plenty of times to me) so how would i work a switch into the circuit?
matroska6 years ago
I just finished a DIY solar usb charger, specificially for my iPod. I already knew that USB voltage varied from 4.5 volts to 5.5 volts.

My multimeter reads right now 5.20 or very close to this; I'm inside and it's night outside. With multiple lamps, that's what I'm reading. Yet my iPod is plugged into my female USB plug (salvaged from a dead motherboard) and nothing shows up.

I used this page for the usb pinouts: http://pinouts.ru/Slots/USB_pinout.shtml

What could I be doing wrong? :O Not enough milliamps outputted makes the iPod think it's still not plugged?

I also tried on a completely dead (battery) iPod, no results..

Thanks for any further help!
also remember to short the two inner USB pins together to force it to charge, no resistors or extra wiring required.
so i took apart an old verizon phone adapter when i got a new phone and threw in a usb port i pulled from a dead board. connected the appropriate cables and my phone charges but not my ipod. so if im understanding your statement correctly inorder for the ipod to charge i need to short the inner two data pins? if this is so why is that?
i'd say most likely not enough current. you would need a pretty big solar panel to get the whole half amp that a USB port should be able to put out. most likely the iPod can sense that and wont charge and/or the iPod's current drain is so high that the voltage drops too low. i would recommend building a solar AA battery charger and then using the charged batteries to power a MintyBoost mp3 charger or some such device.
I don't know if you already fix your problem... but I think you forgot to put an 2.5v connection on pin 2 and 3, this is because USB 2.0 standard give an 2.5 voltage for data pins and ipod need this to charge...(my iPod touch and iPhone needs that) so put a little resistence of 200 kohms from 5v to both middle pins.. (gnd unchanged).. and that work for me..

(I'm great reader but really bad english writer)
theazndan4 years ago
how do you make these lines biased or terminated?
can u play music in your vehicle with this
 Hopefully you aren't thinking that this is a USB port for your car, because then you probably didn't read the instructable, or just deserve a big facepalm.

technoghost6 years ago
thanks for the idea dude heres how mine came out
ichainsaw6 years ago
Here is my rendition: I took an old nintendo DS car charger, stripped it and soldered it to a stripped usb male type B which plugs into a 6 port USB Hub. Now I can charge all my USB accessories from one convenient place!
UrbanWomble6 years ago
This is fun but I bought a very neat and tidy 5V USB adaptor for GBP1.50. As an intellectual exercise, this is fine, but an hour or so of my time has to be weighed up against such a small amount to pay! Have a nice day.
I found this quest on a search of "12v to USB". My purpose for the search to see if any one else was building a BATTERY power to USB for (in my case my Sansa View) that would use one or two 9V batteries to extend the charge of the built-in battery for extended trips (Air Flights, etc...) where the Computer, Wall and Auto chargers would not be available. It seemd to me that using 9V rechargables would be an option if they would deliver their power to the USB like the Wall Charger does. Things I need to find out BEFORE I build the circuit: Does the Sansa View use 5V to charge or does it take more? Does it need the Data pins biased? Will the 9V batteries put out enough current for an extended period of time? I have already built circuits using a 5V regulator with a 9V battery to run pet project that use 4000 & 74LS series IC chips (which gave me the idea for this project). Reason for wanting to do this because the Sansa View battery is NOT replacable!! So what do you guys think??
okreneok6 years ago
I have 5 wires blue, red, white, brown, orange, and on my outlet i have white and red but i tried almost every combination of wires but my ipod does nothing why is this ?
Real Question is how to protect from Over charging ?????? What rate mh and voltage is the safest for the device ?
mspitze7 years ago
For less than $3.00 you can buy one that looks clean.
This thing works great, uses a small buck regulator.
and you can mod it for you needs.
bartax mspitze7 years ago
Agreed, making this is not very practical but could prove to be a good exercise.
They have things like these at target and other places of the sort.
skaterdad7 years ago
So, I didn't have 47K resistors on hand, but had 39k resistors... built it up and 3g Ipod Nano showed "charging" for a little while but then stopped (even though battery not showing full). Also, when it showed "Charging" the menus on the ipod are VERY sluggish.... seems something is wrong here... any ideas?
mamaynhan7 years ago
so when you finished how can we charge our ipod?????
corbettdc7 years ago
ranjeevm9 years ago
Nope! this is the right one!
Drop a pair of your 47K resistors. No need to have two dividers doing exactly the same thing. Simply wire both pins to the same point between the one divider. Save the parts for another project.
now you are defeating the purpose of the voltage dividers. Once again, you have simply created a short.
No you simply are giving +5 to both pins. "Short" technically, but it doesn't matter. Both are at a 5V potential. You are wasting parts to use 4 resistors when you only need 2. Try it you will see.
Just to answer all the recent conversations: Shorting 2 data port for the sake of 2 resistors is NOT a good idea. There is no guaranty that these data points do not try to swing away from a tristate and throw a 1 or a 0 at these ports. If one throws a 1 and other a 0, that would be a dead short-circuit!! I am designing for an 'alien' design and do not want to get into any assumptions and possibly ruin my iPod for a few cents (cent wise and dollar foolish?). Some designers do base theirs on assumptions you see and that's the reason why there aren't many good products out there! Same applies to the 1 ohm resistor. We all know that the internal resistance of a lead acid battery is very low so if a hooked devide draws a surge, that could be enough to blow it off or if you are lucky at least the fuse. The 1 ohm resistor shall 'waste' close to 200mW (cost? Not even measurable in penneys) and give you big time potection. These are my justifications - yours may differ. Just remember that the clutter that some of the comments cause makes the most useful ones invisible to the reader! Thanks!
What if i subbed in a 60 ohm resistor for the 1 ohm. I have no 1 ohms on hand. (of all the values i have lol, i have at least 100 different resistors...) This would simply result in a higher "waste" as you say. If I am using lithium polymer batteries, would I need the 1 ohm resistor?
Be very careful about Li Ion or Li-po batteries as they have the potential to explode and cause fair bit of damage/injury. I have not read up any literature/data sheets pertinent to this and so unable to comment at the moment. If you use a 60 ohm resistor, chances are that the battery will need more than a week to charge instead of a few hours! I would not recommend tinkering with Li-po batteries unless you are sure of the results.
Acutally, the battery pack is an old portable dvd player pack with an internal charging circuit. I am not worried about them exploding or anything because when they are finished charging, the the green light comes on and then the voltage drops across the battery terminals. What i'm doing is building the one all solution circuit shown earlier inside the case of the battery in the extra space in the case. I am getting about 7 volts before regulator and about 4.91 after. I still have yet to get anything to charge though...
Hi, when i opened my car charger thing there was WHITE and RED. When I opened my USB there was white, red, green, and black. I soldered the WHITE and REDS together, will this still work?
Grab the pinout for USB, don't go by the colors. I have seen USB cables with orange and green used for the voltage. The extremely cheap USB cables from the dollar store are usually not colored right.
chr15sc7 years ago
I have used 2 pairs of 20K resistors as voltage dividers. The output of each goes to the D- and D+ separately. This worked straight away.
fedman7 years ago
Help: For my car: Is there an adaptor or solution to allow me to join my existing ipod/stereo connection with a charger line that consolidates into one ipod connection???? In other words, I need to consolidate 2 lines into 1 adoptor to connect to my ipod so I can both charge and play music in my car.
murph38_99 (author) 7 years ago
WoW. I can't believe that the discussion on this is still going strong. Good Job, Inustructables community. Unfortunately, I am not an electrical engineer, but I do have the power of observation. Per my observation, this little device I made over a year ago still powers and/or charges my Nano, My Blackberry, My PSP, as well as a handful of bluetooth headsets. Perhaps the circuitry going to the cigarette adapters in my car has better conditioning than most, but I still have never observed a spike, even while starting, and everything I plug into it is happy.
MegaTesla7 years ago
I struggled for hours but managed in the end to get my iPod Classic Gen 6 charging. Very important: 1) The voltage need to be almost spot on 5V. Even 5.2V doesn't work (backlight doesn't light up). 2) The data lines must be biased/terminated. This was the hardest part to figure out. If pulled up or pulled down too strongly the charger isn't recognised. Even if biased on 2.5V or 3.3V with 47K or 15K and 7.5K resistors it doesn't work. Fiddling with potentiometers I found that equal resistors work, but they have to be of a higher resistance than 47K. I ended up with four 100K resistors. The charger gets recognised immediately. With the Sony Ericsson phone charger (5.00V) that I'm using as power source the charging current is around 320 - 370 mA.
Vovan8 years ago
I bought car FM transmitter

It was not recognized as USB host by MP3 and MP4 players. (both of them transferred power directly to the buttery, and MP3 was destroyed as player)

According to the USB specification

"The Universal Serial Bus Specification (Rev 2.0) mandates the D+ and D- data lines to be terminated with a
15kΩ ±5% impedance."

(see this, for example). My FM transmitter has two resistors, but both data lines was completly isolated from the ground (I guess fabric defect).

After adding two resistors (20kOm), it started to work.

ranjeevm Vovan7 years ago
Vovan the Thevenin's equvalent of two 47K resistors my diagrams above is 23K not too much off from the specs that you cite above. The effect of deviating too much off the 15K spec would be signal reflection and/or non transfer of power on the data lines. Since this is a charger none of the above apply (and the circuit above works!).
ranjeevm9 years ago
Here's the circuit I missed!
While that circuit will work, don't leave it plugged into the cigar lighter socket when not in use. That LM7805 regulates the 12v to 5v by draining the excess to ground. The 1Ω resistor and internal resistance of the 7805 isn't enough to prevent it from draining your car battery dead. Chargers out of China are so inexpensive via eBay, I don't really see a benefit to converting another supply to work.
The cheap chinese chargers pretty much use this circuit or an even simpler one that uses a zener diode .
Doogie LasVegas8 years ago
The 7805 is a series regulator, not a shunt regulator, so it's not shunting lots of current to ground. Quiescent current is only 8mA max so it won't flatten your battery.
Link to page with data sheet:
I'd suggest adding a tranzorb diode type SMAJ18CA in parallel with the input capacitor to stop transients from the starter motor when starting the engine or from the alternator when stopping the engine from damaging the 7805 or your MP3 player.
antennas Doogie7 years ago
Good idea Doogie!
if all else fails, use about diodes in series, the ones I have drop the voltage by about .3 each
The 7805 does NOT "drain the excess to ground" . The regulator generates heat. That's the wasted power being converted to heat during regulation. During no current draw no heat.
Thank you! J
I am no genius, but I see something ODD. The two data lines are not going to ground but have a voltage put on them both. Using off the top of my head electronic knowledge of two 47K resistors, the voltage should be half of 5 volts= 2.5 volts on each data terminal. IS this ok for your device?
hi, ranjeevm , my reply is how do view the circuit well.thank you.
GanadoRH8 years ago
Dollar Tree stores (I'm in TX, not sure of their locations) carry cords with female USB end for $1. That's a good price.

I also got an already built cigar lighter to female USB converter at Big Lots! for only a couple dollars.
by the way nintendo DS adapter seem to be 5V and dirt cheap at game look for the bargain bucket
pbrown37018 years ago
So- i've got a 2nd gen shuffle that i want to use in the car. I'd like to both charge it AND have it play through the amp. Right now, I've got it running through the amp no prob. I've also got a car charger with a USB output. Is it as simple as wiring red and black together and then using black as the audio ground and D1 for right positive and D2 for left positive? Anyone done this?
plingboot8 years ago
This doesn't work with any ipod as suggested. I've a 3rd gen ipod that won't charge via 5V usb - It needs 12V. There's 12V coming out of the cigarette lighter socket - but I'm wary of frying the ipod with spikes / noise. Does anyone have instructions for cleaning or filtering this 12V with a capacitor or whatever? Thanks
Now that USB specification starts out offering 100ma to any device, but then there is a software handshake before the device is allowed to ramp up to 500ma (the hub can even deny that request). So will these simple chargers always be slow, trickle charing at 100ma? Do devices like iPods charge faster or slower depending on the quality (or smartness) of the charger?
DJAndy328 years ago
Awesome, I found this and tried it immediatly. I wanted to do it for my Zune mp3 player, sadly my Zune needs more energy then what my cable dishes out. But it works great for my iPod Mini. :)
spinach_dip9 years ago
Dirty voltage is nonsense for auto's DC system. You can't get much cleaner to start with using DC, plus the car has great voltage regulation. The USB spec for current is 500 mA. So your IPod will charge fine with about anything.
Sorry but there is alot of variation in car voltage, I worked at a semiconductor house and they wanted devices to survive 80V spikes to -40V reversed polarity. Doogie above has the best suggestion - original circuit with a surge absorber. cheers!
Have you ever hooked a scope up to a car's electric system? Among other things, you'll see large "load dump" spikes due to the large inductance of the alternator windings storing current. Especially during starting. The wiring harness is notorious for picking up EMC, especially from the electronic ignition system. Automotive electronics generally are protected against extended overvoltage, reverse-voltage, and voltage peaks of over 100V. Multi-KV ESD is also common, and causes lots of failures. Look at this Harris app note http://www.eetchina.com/ARTICLES/2003MAY/PDF/2003MAY26_POW_AN04.PDF for more on this ugly power source.
In fact, connecting a 7805 directly to car supplies is extremely risky, as the 7805 is only rated to 37V!
maddog818 years ago
I currently own a Nokia 6315i. I have a USB charger for my Nokia 3589i. I want to make one that plugs into my comptuer for the 6315i. If this process listed here can work the same, but have the male end of a USB cable attached to the end of a charger that goes into my cell phone.
dale3h8 years ago
It seems that an easier way to do this would to buy a mini-B 5 pin USB car charger, and then make an adapter. Any ideas on why this wouldn't work?
Bohemian9 years ago
I found this site on making a 12v to 5v converter. http://www.seetron.com/an_vpwr1.htm I am hoping to be able to power a small usb hub with it for power outs.
Unless the power adapter you use has built-in power filtering and regulating, DO NOT USE IT!!! (For an analogy, would /you/ drink out of any major river in your area? That is the kind of 'dirty' power that exists in the auto environment.) Bohemian's circuit includes both the filtering and regulating that is needed to keep your devices safe. If you are only using an MP3 player, you can probably get away with the cheaper linear reg, as they don't use much in the way of amps. It even looks simple enough to not need a circuit board. Just lay out the parts to fit in some small enclosure, overlap the wires, solder them together, then coat the whole thing (except the heatsink, of course) in 'liquid insulation'. C'est facile, n'est pas?
In place of the 5 volt regulator(7805), which specifies it can give a max current of 1A, isn't it possible to connect a variable regulator like the LM317 which can deliver a max current of 1.5A, and accordingly adjust 5V output?
ranjeevm9 years ago
Take any un/regulated car charger. Check the output voltage. Open it if possible/safe to see if you can locate large capacitors of 100mfd and above and ICs or transistor. Case1: Output less than 4.5V: If this charger is not being used, empty out the contents and replace with the circuit below. If the charger is being used, see if you still have the room to accommodate the circuit. If not use a small plastic box connected to the charger. Case2: Output more than 5V: Example 6V or 7.5V or 9V: Check for adequate filteration(caps more than 100mfd) and regulation (ICs and transistors). If yes, the conversion could come for free(almost!).Use series diodes to drop voltage in multiples of 0.7V. A 10mfd capacitor may be added at the output but is not compulsary. Case 3: Output is 12V: Just use the circuit below. For all the above cases, do not forget to add the output 47K circuit. If you do, video Ipods will not work!!It seems that the unused USB ports must be tristated(do not panic if you do not understand what this means!)
see ranjeevm8 years ago
Hi ranjeevm, I'm not very clear about what you say for video ipod. some more I found that the Ipod charging is very slow. Can you pls advice? Thanks!
ranjeevm see8 years ago
I was just saying that the 4X47K resistors shown in the circuit cannot be done away with if you need reliable charging. iPod may charge slowly at voltages lower than 5V so ensure an output of about 5.6v to get a fast/reliable charge. How to get 5.6V from LM7805... look at the modified circuit above.
ranjeevm8 years ago
Oops.. Looks like I missed a lot of action. Well guys if you need any help pl let me know. My own creations are working fine both at home and my car. Since I had posted the circuits, the cost of iPod chargers have drastically come down in the market < $5 so buying a ready made car/mains charger could prove cheaper and more reliable!
Karsten9 years ago
Excellent! One additional hint: This cirquitry didn't work immediately; I had to put the voltage devider bridge a little out of ballance. I got success with the above cirquitry (4x 47K) when I connected one additional 47K resistor parallel to a bridge resistor. Finally I use 47K-47K on one branch, and 39K-22K on the other, and pulled one (Green, I think, the one closer to GND on the USB connector) a little lower (22K to GND, 39K to +5V). This modification is backed by the measurement that I made on a working power plug charger, here the white/green voltages were as well significantly out of ballance. So, if you can measure the current and verify that the proposed cirquitry works for you, and shift the ballance a little if required. -Karsten
Your IPOD must be touchier than mine. I connected a 1K resistor from pin 2 to pin 3. The IPOD (5G, 30GB), was satified that this was "tri-stated" enough, and merrily started charging almost immediately. By the way, I connected my auto adapter to a bench supply while charging the IPOD; I measured a little over 125mA. I think the unit was already mostly charged, so maybe it would draw more current if the battery was in a more fully discharged state. I only responded to this because I couldn't get my power supply to charge the IPOD until I saw someone's post in this site about resistance across the data pins. SO I am passing it on. - d.
StarBlades8 years ago
wvanduser9 years ago
What is that clipped to the back of your iPod nano?
DKNY20009 years ago
hi guy's i have a BNC GPS Antenna & i want to chang the BNC connection to USB connection in order to use the antenna with my laptop can any one help me ? best regards to all
ProfTheory9 years ago
I would agree with DeadlyDad that using a volt-meter won't show the 'noise' present. Also don't rely on wire color alone, double check by using the ohm setting on the meter to verify the pinout of the USB cable and the power adapter. Don't anything. Also the point DD was making about the car when starting is that when the starter motor is disengaged that there is often a large voltage spike that the meter won't show. 7 3
edy9 years ago
Hello, I charge my iPod nano using the same "wall-wart" that my iRiver SlimX 350 uses to charge. It outputs 5 VDC so I just made an adapter to fit a USB female type A port. For those who don't know, the SlimX is a CD-based MP3 Player that used to be made by iRiver (www.iriveramerica.com). It turns out the SlimX charger (which says 4.5VDC 650mA) actually reads 5.0 V on a voltmeter. Therefore, you can just hook up a female type A USB port to the plug (just make sure the polarity is correct) using an alligator clip to hold a wire on the outside, and the other wire you can just stick into the hole of the plug. It works fine for charging my iPod nano. Because I didn't modify the wall-wart plug at all, I also use it to charge my SlimX 350. I had my "wall-wart" free because I already had a SlimX. Some of you have old cell phone wall-warts but they can be slightly different voltages. But you can buy only the "wall-wart" directly from iRiverAmerica for $7.99. Go to iriveramerica.com and click on E-store, then Accessories, then CD Accessories and look for the charger. I got my female USB port from an old computer, just cut it off the motherboard and soldered some wires onto the correct pins (1 and 4) with the alligator clips. Now if I travel and I'm not near a computer, I can charge directly from the wall outlet. You can pick up a wall-wart and USB female type A for nothing at any electronics surplus store and make the charger yourself. Edy
msteger9 years ago
Hi, I built an adapter out of my Nokia cell phone charger (ACP 12E). It is spec'ed to have 5.7 V with a max of 800 mAh. Plugging it into my iPod Nano looks fine at first. The charge Icon comes up and after a while it even says Charged. But after unplugging it it turns out that the battery level is actually lower than before starting to charge it. Don't know what to do now... (iPod still charges at my pc)
manishr9 years ago
I recently bought a cheap USB charger that has a 5v output. But to my dismay this charger has a 350mA current output. I am unable to charge my iPod as the requirement is a minimum of 1 Amp. How is it that none of you faced this problem. Does the Motorola Wall adapter deliver 1A of current. Can anyone give me the list of other cell phone chargers that deliver 5V of output
towyou889 years ago
I tried the exact thing as making the adapter for a LG vx8100mand still be able to power my pda and my cell phone if I needed to. As soon as conected the female end with my phone male end the car adapter turned off when connected to a wall adapter. What????? Will this only work if the car adapter is plugged into the car itself??
DeadlyDad9 years ago
<SIGH> I've heard the same (somewhat valid) argument used by clients who insisted that their power bar (without a surge protector) has worked just fine for the last five years and they don't see why they should pay a lot of money for some gadget that won't work any better. They are right; a surge protector /won't/ do any more for them.....until they are hit with a power surge. Then that $40 investment makes a *LOT* more sense. I estimate that I have invested over four hundred dollars in surge protectors in the last sixteen years, and have replaced the MOV's in four of them after they 'died' taking a hit that would have cost me /thousands/ in repairs & replacement, let alone time. I consider the money well spent.

In the same way, Bohemian's circuit is pretty cheap insurance against problems in your car's power. Even if you go with the more expensive switched reg, it shouldn't cost more that $30, and you can probably build the cheaper one for less than $10.

BTW, be /very/ careful if your cigarette lighter powers up /immediately/ after you turn the key. There's a reason why your radio, etc. doesn't come on right away - the power is too unstable until the engine is running.
murph38_99 (author) 9 years ago
In response to DeadlyDad, I rode around for around an hour in city traffic and highway traveling (to simulate spikes through the electrical system) and had gator clipped a rig similar to this to a voltmeter, and reported no spikes in voltage. Typically the voltage ranged from 5.15 to 5.03 under hard accelleration. Unless my car (infiniti, which has grouding issues i might add) has a regulated circuit where the adapaters are, I don't know what else to say except that the setup was reliable, and reported no dirty behavior. Perhaps I'm missing something
murph38_99 (author) 9 years ago
Since making this I also realised that 2 other things could be done in this manner. First, you could make an extra wall charger by using the motorola wall adapter (Model:PSM4680A) since it also has a 5v output. Secondly, you can use the unused male end of the usb extension cable spliced together with the part that plugs (the part you clipped off) into the phone, and still use the charger as a phone charger as well, simply plug the male end back into the female USB end and presto, you still have a functioning car adapter for your phone.
I found this site on making a 12v to 5v converter. http://www.seetron.com/an_vpwr1.htm I am hoping to power a small usb hub for power outs.