Small USB Cellphone Charger - A little help is needed.

ian field

Joined Oct 27, 2012
6,536
Ok, just about fed up with this project, even though I haven't received anything yet.. So I went and bought this on Amazon Prime. It will be here Thursday. This will allow me to use less 26650 Batteries to power my circuit, and if I read the specs properly, I'll be able to use only 1x MNKE or Efest 26650 (3,500mAh) Battery with this circuit, rated at 4.2vdc (3.7vdc Nominal). That means I can use 4 of these 26650 Batteries in Parallel and have my 7,000 or 14,000mAh Battery pack up in running,.
If you're going totally DIY on this, I'd recommend a single cell or cells in parallel - definitely not series cells.

Manufacturers that make series packs have to include complex charge balancing circuits, and seal the pack to eliminate tampering - charging series cells can be potentially dangerous if you're not careful, some big brands have come unstuck as can be clearly seen in Youtube clips of laptops etc impersonating a flamethrower!

The single cell option dictates the use of a flyback/boost converter to step up to 5V - you could do worse than the MC34063, there are plenty of circuits online and a couple of online component calculators that pretty much design it for you.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
Went and bought myself a 30 watt Soldering Iron. $10 @ RadioShack.. It's not a $150 Weller or a Hakko Adjustable Wattage or Temperature Soldering Iron, but it's a start. Christmas is right around the corner, and I'm spending too much on this project.

IMG00000001 2014.11.05 03.12.17 PM.jpg

My UNI-T UT61D True RMS DMM will be here tomorrow, along with my helping hands. I don't know if you caught it.. but I got my $9 Step up Module today too.. :) Along with the 2x 1.5FT A Male to A Female USB Gold plated cables from MONOPRICE. I went and cut em and took a look at the wires, little anxious to get this project started, and start testing things.. I don't think my 26650 battery sleds will be here anytime soon from VAPE3D. I ordered 2x 26650 sleds that hold 2 batteries in series.. then I think it was either yesterday or the day before, I ordered but yet another one.. But this one holds 2x 26650 batteries in parallel. The Parallel one will be used for the above step up module.


Here's what the module looks like a little closer.
IMG00000001 2014.11.05 03.22.16 PM.jpg
IMG00000001 2014.11.05 03.22.36 PM.jpg IMG00000001 2014.11.05 03.22.45 PM.jpg
 

wayneh

Joined Sep 9, 2010
17,496
Went and bought myself a 30 watt Soldering Iron. $10 @ RadioShack.
Here is the type that I (and some others here) have got. I like it far more than the type you pictured, and if you watch for sales it is not much more expensive. For one thing, replacement tips are more available and not expensive.
My UNI-T UT61D True RMS DMM will be here tomorrow, along with my helping hands.
Are you familiar with Harbor freight? I got my DMM and helping hands there for less than $5. The DMM was free and I think the helping hands were $2.99 or something like that.
 

takao21203

Joined Apr 28, 2012
3,702
Here is the type that I (and some others here) have got. I like it far more than the type you pictured, and if you watch for sales it is not much more expensive. For one thing, replacement tips are more available and not expensive.
Are you familiar with Harbor freight? I got my DMM and helping hands there for less than $5. The DMM was free and I think the helping hands were $2.99 or something like that.
Its TRIAC controlled, not temperature controlled. This has several disadvantages.

Also if you dont use a permanent tip, the copper ones dont last long.

A temperature controlled station 50W with display is pretty standard and simply gives you better results.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
Ok... the circuit works. The circuit using the SPX2940 VLDO Voltage Regulator IC. Did a video on it, seems to charge 1% every 13m. So I take it, it's not charging at 1A. I'm gonna upload a video showing it charging from 81% to 82%.

The cheap 30 Watt soldering iron I bought from RadioShack for $10+ works very well. I tinned my iron tip, etc. Works very well so far.

Turns out needed to join the Data (+) & Data (-) together. :)

IMG00000001 2014.11.06 06.07.03 PM.jpg


The Soldering Iron works very well. I was thinking of getting the same Soldering Iron Station, Tony Stark was using in Iron Man 3.

Weller WES51 50Watt. But I think I'll save my $100, seeing that the really cheap ($10+) Soldering Iron works very well.

IMG00000001 2014.11.06 05.57.53 AM.jpg

I tried the circuit with & without the Capacitors recommended on the Data Sheet for this VLDO Voltage Regulator. It charges it regardless. It's probably not needed, seeing that it's DC voltage anyways, and I'm not converting to DC from AC Voltage using a Full Wave Bridge Rectifier and a 120vac to 12vac transformer...

I have a problem though.. Tried measuring Current from my USB 2.0 & USB 3.0 port om my laptop, using nicely spliced wires from the USB Cable I bought from Monoprice. It doesn't show any current.

I also tried measuring current with a load on the circuit I built, via the Cellphone charging, and can't get a reading. My UNI-T True RMS Mutlimeter says 0.0000 A.

WTF...?

I even tried uA, NOTHING.

Yes, I put the black lead into the Port labels for testing current, and NOTHING.

Maybe I'm doing something wrong.. It's a very nice True RMS DMM.

The voltage on the load on the circuit, on the solderless breadboard measures 4.700vdc. So there's a 0.300vdc drop when the Samsung Galaxy S3 is charging.

Also.. when I plug the phone into the circuit, the phone gives me a Notification, and then the phone starts charging. I'm very pleased with that. The circuit is clearly working with my Samsung Galaxy S3, but I don't know how fast it's charging.
 

ISB123

Joined May 21, 2014
1,236
You need to plug the red probe from multimeter in 10A port of multimeter to measure current.

From manual:

To measure current, do the following:
1. Insert the red test lead into the mA or A input terminal and the black test lead
into the COM terminal.
2. Set the rotary switch to A, mA, or A.
3. The Meter defaults to DC current measurement mode. To toggle between DC
and AC current measurement function, press BLUE button.
4. Connect the test lead in serial to the return circuit to be tested. The measured
value shows on the display.


BLACK IN COM
RED IN 10A
 
Last edited:

Papabravo

Joined Feb 24, 2006
21,159
On a slightly different, but related topic, it might be useful to review the USB interface. In the USB 2.0 specification it defines an interface with four wires implemented as two twisted pairs. A power pair and a data pair. The data pair, labeled D+ and D-, is used to exchange data between two devices. The power pair will provide 5V @ 100 mA by default. A device can negotiate, by exchanging data messages, with the provider of the power for an increased amount. I believe that increased amount is 5V @ 500 mA. A device that tries to negotiate with a simple charger will obviously not get any meaningful response, but it will by default get more current than it expects. This may or may not be a problem for the device. It may or may not result in damage to the device. Without knowing more about the device it is hard to speculate. If I was doing this I would get a USB protocol analyzer and capture the traffic between a cellphone and a factory approved charger just to see what happens. Armed with this knowledge I would then go about designing a charger that would be guaranteed not to damage the phone.

I would not expect a beginner in electronics to know or be aware of this stuff, that's why I'm offering my $0.02 worth.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
You need to plug the red probe from multimeter in 10A port of multimeter to measure current.

From manual:

To measure current, do the following:
1. Insert the red test lead into the mA or A input terminal and the black test lead
into the COM terminal.
2. Set the rotary switch to A, mA, or A.
3. The Meter defaults to DC current measurement mode. To toggle between DC
and AC current measurement function, press BLUE button.
4. Connect the test lead in serial to the return circuit to be tested. The measured
value shows on the display.


BLACK IN COM
RED IN 10A

Thanks ! I'll try it. YEP. It works..

Why is it only outputting 35.18mA ?


This is my video. It shows the circuit charging 81% to 82% in 13 minutes. Be sure to watch in 1080p.

I recorded this with a Panasonic Lumix LX7 @ 1080p @ 30 FPS @ 20Mbps.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
I hooked it up this way, and measured the current from the GND & Vout.

Ok.. Measured it again.. It reads... 2.979 AMPS.

When I test it, it get's really hot.

So.. Idk. These pictures are for testing the current. When I tested it one way it shows 34.99mA, when I test it another way, it reads 2.979 Amps.

IMG00000001 2014.11.06 08.21.31 PM.jpg IMG00000001 2014.11.06 08.20.15 PM.jpg


I also tested it the other way on my Lenovo IdeaPad Y570 Laptop..

This is what it reads.. Using Max again so I can take a picture of it. 0.872A (USB 3.0) That's what it reads for a USB 3.0 port. I have 2 on the right of my laptop, and 2 USB 2.0 on the left.

It reads 0.872A Which is what USB 3.0 is supposed to be.

P1040769.JPG



So.. I'm getting 2.9 Amps from the VLDO Voltage Reg. IC ?
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
Oh.. and here's some nice pics of my 1st & 2nd time soldering. Using a $10 30 Watt Soldering Iron from RadioShack. :)

Also a look at the circuit. :) Without the stupid capacitors on it. I took them off. I have the correct capacitors for the circuit, that's mentioned in the data sheet. I even hooked them up, if you watched my video.. But I don't like them.. I took them off. The circuit is much more simple now.


This is my first solder job, I ever did. Never touched a solder iron before.
A.jpg

This is my 2nd & 3rd time..
B.jpg C.jpg

This is what the circuit looks like.. without capacitors on it. It's not AC, so I don't see the need to use them.
D.JPG
 

ISB123

Joined May 21, 2014
1,236
You need a capacitor or voltage regulator wont be stable and will have noisy output.
They are talking about 0.1uf capacitor which isn't needed unless you have high AC impedance.
 

takao21203

Joined Apr 28, 2012
3,702
With batteries you could omit that capacitor or so I was thinking...batteries after a while can develope weird crystal structures so you get oscillations too. You should have a 1uF to 10uF capacitor close to the regulator, on both sides.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
With batteries you could omit that capacitor or so I was thinking...batteries after a while can develope weird crystal structures so you get oscillations too. You should have a 1uF to 10uF capacitor close to the regulator, on both sides.

When I go to put it into a more permanent configuration, I will.

The data sheet tells me to use a 25v @ 10uF and a25v @ 6.8uF Electrolytic Capacitor, so that's what I bought. I used them when I first tried the circuit out, and it works with or without the Capacitors. But when I go to solder it in a perf board, I'll use them for the final build. I'm using a heatsink that RadioShack included with the 30 watt soldering iron. It works pretty well actually.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
You need to plug the red probe from multimeter in 10A port of multimeter to measure current.

From manual:

To measure current, do the following:
1. Insert the red test lead into the mA or A input terminal and the black test lead
into the COM terminal.
2. Set the rotary switch to A, mA, or A.
3. The Meter defaults to DC current measurement mode. To toggle between DC
and AC current measurement function, press BLUE button.
4. Connect the test lead in serial to the return circuit to be tested. The measured
value shows on the display.


BLACK IN COM
RED IN 10A
Thanks, I've posted the results. Much better, thanks for the help.
 

Thread Starter

Guest3123

Joined Oct 28, 2014
404
With batteries you could omit that capacitor or so I was thinking...batteries after a while can develope weird crystal structures so you get oscillations too. You should have a 1uF to 10uF capacitor close to the regulator, on both sides.
Thanks, I'll keep that in mind when I make it permanent.

As for the iPhone 4S. IT WORKS. Here.. take a look.

For best viewing experience, please be sure to watch in 1080p.

Recorded with Panasonic Lumix LX7 @ 1080p @ 30 FPS @ 20Mbps.
 
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