DC to DC Multi-Purpose Voltage Converter $14.98

[Lyen]

I use an iPhone 4 for navigation and have been trying to power / charge it with one of these converters set at 5V and powering a USB charging cable - cannot get it to work, any suggestions?

Phil

Hi Phil,

The iPhone 4 needs to sense voltage on the USB data pins. Its wall charger definitely outputs 2V & 2.7V on the two USB data lines, as well as the 5V on the USB Pwr pin.

If you have some electronics experience, follow the instructions below to construct your own charging adapter cable.
If you never soldered before, then don’t try. If you connect things wrong there is the potential risk of damaging the phone.
As usual, if you do make your own cable, you do it entirely at your own risk. If your phone dies, do not blame me. Mine is working fine, so the procedure does work if done properly.

Instructions:
READ ALL STEPS BEFORE STARTING WORK!
The USB has 4 wires:
Red-5V, White-Data, Green-Data, Black-Gnd.
They are numbered Pin1 to Pin4, in the same order, ie Red =Pin1.
1. Cut the USB EXTENSION lead, trim both pieces to a shorter size, but make sure you leave enough length to work with !
2. Cut off the foil-shielding on both pieces, twist the braided wire shielding into a single “wire” on each piece.
3. On the female piece of the lead solder resistors as follows:
Pin1—R1—Pin2—R2—Pin3—R3—Pin4—Shield
R1=2K2; R2=680; R3=2K2
4. Trim resistor legs as short as possible. Make sure you put some insulating tape between all the exposed bits of wire and resistor legs. You want to pack the resistors as tight as you can, and you do not want any metal bits touching!
5. On the male end of the lead, cut off the white and green wires; you DO NOT want to connect them to anything! If they were connected it would feed power back to the car adapter, which could conceivably have those pins grounded as they’re usually not used (hence the iPhone 4 charging problem).
Even worse, you might one day accidentally plug this new DIY adapter cable into a USB port on your PC, and it may take offense at having power coming in on the data lines.
So cut the green and white wires on the male end.
6. Cut a piece of large-diameter heat-shrink and slide it over the male piece of the lead. It should be long enough to later cover the area where the resistors are. Hence the male end of the lead needs to be at least as long as the length of heat-shrink you need!
7. Join the two pieces of lead by soldering the male red wire to the female red, male black to female black, the shields to the blacks.
8. Carefully compact all the resistors together, ensuring there is insulation between adjacent metal parts, and that nothing comes lose. You might need to think about how you want to pack the resistors BEFORE YOU SOLDER!
Then slide the heat-shrink over the resistor assembly until it overlaps the untouched part of the the USB cable on both sides of the resistor assembly.
Heat up heat-shrink to make it grip.
* If the assembly is bigger than the heat-shrink you chose, remove heat-shrink and tightly wrap the entire cable with electrical tape instead. Done!
9. WAIT! DO NOT CONNECT iPhone, yet!!!!
10. Connect your new adapter cable to the DC-DC converter.
With a multimeter (and thin probes, or bit of stiff wire soldered to the probe tip) measure the voltages you get on the female end of your new adapter cable.
Put the Gnd-Probe on the plug shield, and be extremely careful with the other probe not to touch both the shield and a pin at the same time.
You should have ~5V on Pin1, ~2.8V Pin2, ~2V Pin3, 0V Pin4.
If you do, Congratulations, you now have a USB adaptor cable that will turn any plain USB voltage adaptor into an iPhone 4 charger.
If you have no voltage, you might have forgotten to solder the shield to the black. Put Gnd-probe on Gnd-Pin4, then measure all other pins and shield. If the pins measure ok, and the shield is still 0V, you are probably ok too.
All other results, and you need to re-do your cable!
11. IF YOUR CABLE MEASURES OK, at your own risk (!) you can now connect your iPhone to the adapter cable, and then into the DC-DC converter. It should now charge.
Note: Apple states that the iPhone should only be connected to authorised chargers,etc. Using the DIY adapter cable could potentially void your warranty.

Please be careful though :
When cutting an USB extention cable : Do not rely on the wire colours !!!
Mine had red colour connected to pin2, black wire connected to Pin 3, green (5V) connected to pin 1 and white connected to Pin4 (GND)
Measure twice !

Regards,
Lyen

[wojtek]

WOW Lyen, that is impressive!!!

[ChinaPhil]

I use an iPhone 4 for navigation and have been trying to power / charge it with one of these converters set at 5V and powering a USB charging cable - cannot get it to work, any suggestions?

Phil

Hi Phil,

The iPhone 4 needs to sense voltage on the USB data pins. Its wall charger definitely outputs 2V & 2.7V on the two USB data lines, as well as the 5V on the USB Pwr pin.

If you have some electronics experience, follow the instructions below to construct your own charging adapter cable.
If you never soldered before, then don’t try. If you connect things wrong there is the potential risk of damaging the phone.
As usual, if you do make your own cable, you do it entirely at your own risk. If your phone dies, do not blame me. Mine is working fine, so the procedure does work if done properly.

Instructions:
READ ALL STEPS BEFORE STARTING WORK!
The USB has 4 wires:
Red-5V, White-Data, Green-Data, Black-Gnd.
They are numbered Pin1 to Pin4, in the same order, ie Red =Pin1.
1. Cut the USB EXTENSION lead, trim both pieces to a shorter size, but make sure you leave enough length to work with !
2. Cut off the foil-shielding on both pieces, twist the braided wire shielding into a single “wire” on each piece.
3. On the female piece of the lead solder resistors as follows:
Pin1—R1—Pin2—R2—Pin3—R3—Pin4—Shield
R1=2K2; R2=680; R3=2K2
4. Trim resistor legs as short as possible. Make sure you put some insulating tape between all the exposed bits of wire and resistor legs. You want to pack the resistors as tight as you can, and you do not want any metal bits touching!
5. On the male end of the lead, cut off the white and green wires; you DO NOT want to connect them to anything! If they were connected it would feed power back to the car adapter, which could conceivably have those pins grounded as they’re usually not used (hence the iPhone 4 charging problem).
Even worse, you might one day accidentally plug this new DIY adapter cable into a USB port on your PC, and it may take offense at having power coming in on the data lines.
So cut the green and white wires on the male end.
6. Cut a piece of large-diameter heat-shrink and slide it over the male piece of the lead. It should be long enough to later cover the area where the resistors are. Hence the male end of the lead needs to be at least as long as the length of heat-shrink you need!
7. Join the two pieces of lead by soldering the male red wire to the female red, male black to female black, the shields to the blacks.
8. Carefully compact all the resistors together, ensuring there is insulation between adjacent metal parts, and that nothing comes lose. You might need to think about how you want to pack the resistors BEFORE YOU SOLDER!
Then slide the heat-shrink over the resistor assembly until it overlaps the untouched part of the the USB cable on both sides of the resistor assembly.
Heat up heat-shrink to make it grip.
* If the assembly is bigger than the heat-shrink you chose, remove heat-shrink and tightly wrap the entire cable with electrical tape instead. Done!
9. WAIT! DO NOT CONNECT iPhone, yet!!!!
10. Connect your new adapter cable to a car USB adapter.
With a multimeter (and thin probes, or bit of stiff wire soldered to the probe tip) measure the voltages you get on the female end of your new adapter cable.
Put the Gnd-Probe on the plug shield, and be extremely careful with the other probe not to touch both the shield and a pin at the same time.
You should have ~5V on Pin1, ~2.8V Pin2, ~2V Pin3, 0V Pin4.
If you do, Congratulations, you now have a USB adaptor cable that will turn any plain USB voltage adaptor into an iPhone 4 charger.
If you have no voltage, you might have forgotten to solder the shield to the black. Put Gnd-probe on Gnd-Pin4, then measure all other pins and shield. If the pins measure ok, and the shield is still 0V, you are probably ok too.
All other results, and you need to re-do your cable!
11. IF YOUR CABLE MEASURES OK, at your own risk (!) you can now connect your iPhone to the adapter cable, and then into the car adapter. It should now charge.
Note: Apple states that the iPhone should only be connected to authorised chargers,etc. Using the DIY adapter cable could potentially void your warranty.

Please be careful though :
When cutting an USB extention cable : Do not rely on the wire colours !!!
Mine had red colour connected to pin2, black wire connected to Pin 3, green (5V) connected to pin 1 and white connected to Pin4 (GND)
Measure twice !

Regards,
Lyen

Lyen, thank you. I will give this a go after I have been resistor shopping. Hope that your instructions help others.

Phil

[NeilP]

I'm wondering how clean (ripple) the DC voltages are from those small units? Do you have a oscilloscope by any chance?

Ambrose

I did think about going down to a mates to try a scope on the output of the small SMPU's that I got from th dump and ran at 84 v or less from my bikes pack,and have not got round to it yet, but it has occurred to me that , even if he did, the results would be meaningless to you unless you had the exact same model power supply.

As far as I understand, since these are switched mode units, the input is going to have absolutely no bearing on the smoothness of the output, this is solely going to be a factor of the design of that particular supply, so any results I may find from the SMPSU's I have would be different for any supplies you find.

I may still go ahead and try and see the chap, and give it a try, just out of curiosity now, but I do not thing it will produce any useful information.

As for going below 84 volts...not sure what voltage I initially tried this out at, when I first tried running one of them off DC, but it would not have been a fully charged pack in any case...it would have at least been down to about 75 v by the time I had got to the farm workshop, where I do all my bike building

Neil

[ChinaPhil]

Confirming that Lyen's iPhone charging instructions work, thank you once again.

Phil

[jonathanm]

Want one of these to hook up my android phone for using speedict ebike.....payment sent!

[ohzee]

bought one - 2nd item I have bought from Lyen and his shipping is IMPRESSIVE to say the least.

Placing a 2nd order now.

[geoff57]

Hi
Iphone charger.
For those that worry about getting the resistors correct there is an alternative, iphone car chargers with built in cables to a iphone for not a lot of cash, if opened up you will find that most if not all only have 2 wires coming down the cable, the resistor network is hardwired into the connector.this means that there is an alternative charger that requires no skill in getting resistors in the right order.

1: prepare the power in to the DC to DC converter in the same way as in the previous instructions. Connect Positive (60V to 8V) and ground to ground, if using a battery then fit it between the battery and V IN + if fitted on the V O + side then the DC to DC converter will be draining the battery all the time and if lithium with no LVC protection the battery could well end up discharged beyond repair.
2: you now have the Converter connected to a power supply (battery or mains PSU), take a multimeter put it over V O + and V O - turn the screw pot untill the meter reads 5.1V. Now disconnect the power supply and get ready to do the rest of the soldering.
3: check which is the positive and negative wire in the charging cable you have, (if there are more than 2 wires the cable is not a charging cable but a data cable) most probably the wires will be Red and Black but don't rely on the colors.
4: once identified solder the lead to the V O+ and V O - positive and negative respectively.
5: the output wires are probably very thin and only PVC insulated, for the wires strength and insulation cover the 2 wires with heat shrink to where the wires are striped, on the connection either use heat shrink if it is possable or if on a circuit board use silicone or epoxy glue don't use heat melt glue as when in use the converter gets hot.
6: put the whole thing into a small case plastic or metal, the heat from the converter will not be enough to melt a plastic one( it has never melted mine anyway ) you just have an input wire an output wire and an optional switch on the box.

I made my charging unit soon after this thread started so that I could charge my iPad from a LiPo battery pack the converter gets very hot but I have had no problems when charging my iphone it charges like its on steroids.

This build is in effect the same as was described above it just avoids working out where to put the resistors, infant the resistors are not needed.

Geoff

[hillzofvalp]

For those of u who have a 12-24V auxiliary supply, many of the car USB ports regulate this range. I got mine for free at a job fair booth, but I'm sure you could get one for less than $5. It's only 700mA though... I can't remember what the highest the iPhone can take

[nonlineartom]

Personally I just have the DCDC converter running at 12V and then use a cigarette lighter USB charger to charge the phone up. I know it's effectively 2 DCDC converters but it gives the iPhone power it's happy about and doesn't risk damaging the phone. I'm guessing it uses some kind of regulator built it. Doesn't add much bulk

[gurshark]

Sent payment for two at 12:55am on 12/5/12. The one I bought from cell man just died after a week of use, but this is so useful, I want to try again and hope the dead one was just defective. Stepping 48v down to 14 to power a 1 amp light.

[gurshark]

FYI. Don't reverse the input polarity. That cap blew spectacularly last night.

Lyen, is the amount of heat the converter generates dependent on how much you are stepping down the voltage?

[geoff57]

Hi
I'm not lyen but I can answer that. First your comment on reverse polarity on the input, I did it once never again with me the chip exploded with one hell of a crack.
As for the heat generated it is linked to the wattage output not the ammount steped down, I use one to charge my iPad or iphone, set to 5.1V output weather I put a 3 cell lipo,5 cell or 10 cell the heat produced by the converter is a lot almost too hot to touch, by comparison I have a converter on my bike with the input side being my 12 cell battery pack just over 50V fresh off the charger, the output is to bank of Cree front led lights switchable from 1 to 4 . The output from the converter is set to 3V to give the LEDs long life, each pull 1W even with all 4 on the converter stays cool the same temp as when off where as the converter for the iphone which I am using as a sat nav is warm but not as hot as when charging the iphone/iPad from close to flat.
Hope that was not too long an answer to how much heat the converter produces and when.
Geoff

[Merlin]

hello,
can someone maybe help me?
i recieved also one from lyen, but when i connect a 6S Lipo (25,4v) incoming there comes nothing out... 0,0v
i tried to screw in any way 360° and nothing comes out.

any idea?

[yopappamon]

hello,
can someone maybe help me?
i recieved also one from lyen, but when i connect a 6S Lipo (25,4v) incoming there comes nothing out... 0,0v
i tried to screw in any way 360° and nothing comes out.

any idea?

I believe it is a multi turn potentiometer. Verify that you are putting the power in the input, and that positive and negative are correct. Then turn the screw several turns one way, if nothing, then go the other.

[Doctorbass]

Bought 2

Thanks Lyen!

Doc

[Merlin]

I believe it is a multi turn potentiometer. Verify that you are putting the power in the input, and that positive and negative are correct. Then turn the screw several turns one way, if nothing, then go the other.

thx, will try it

[Merlin]

have tried....unbelivable....i have to turn 20-30 times to increase voltages....
but below 7,5 it goes straight "off" and there comes 0 volt.

Thats not cool because i want to use 5v to charge PDA/Handy/Navi