Just the truth. Cell phones fast charging cables 2.4A & micro or B, USB plugs

[Kiriakos GR]

Here is the shortest sincere pack of information’s about mobile phone charging cables and also about micro B USB specifications’ this including USB 2.0 and USB 3.0

I am just few days away, from entering my self also in the group of smartphones owners.
My inquiry about discovering quality accessories for my Samsung galaxy S5, made me notice some sort of misinformation game, leading people spending money at cables them able to handle 2.4A Max

Now let’s see some facts.

1) Micro USB connector for PCB (mounted over the phone), Electrical specification:
Max current Rating 1.8A (Pin 1 & 5)


2)  USB 3.0 & 3.1 ( Micro USB B) Electrical specification:
This is 900 mA Max with High speed connection active.
1,5A Max charging / No Data connection


3)   USB micro soldering pads.
According to soldering pads dimensions 22AWG seems to be 100% compatible especially after soldering.
20 AWG will cause soldering overflow and for mass production cables this will be avoided.
18AWG can be used with significant difficulty as this is 25% larger in diameter from the pad it self, only hand soldered DIY cables can be made that way.

18AWG max current at 30C = 4.9A
20AWG max current at 30C = 3.5A 
22AWG max current at 30C = 2.1A

 
4)    Cell phones charging system no matter manufacturer or model, max allowed charging current this is 1.7A or lower.
Cell phone manufacturers like Samsung and others, they are obligated to follow USB micro &  USB micro B female plug electrical tolerance specifications.


5) Since 2014 New Samsung Fast chargers they are specified as 5V 2A or 5.3V 2A.    
This is Max electrical specifications of the charger it self when this is tested with a resistive load.
a) True output in VA from 5V 2A this is 5Vx1.7A = 8.5 VA (usable power by the phone)
b) True output in VA from 5.3V 2A this is 5.3Vx1.7A = 9 VA (usable power by the phone)


6) Newest Adaptive Fast Charging (charger) this is 9V 1.67A and also specified as 5V 2A.
First conclusion this is that even if your phone this is 100% Adaptive Fast Charging compatible, active Qualcomm fast charging will never require more than 1.67A.
Higher charging power in VA this is possible due keeping the current parameter fixed at 1.67A and by further elevating voltage parameter.
True output in VA from 9V 1.76A this is 9x1.67A = 15.3 VA.
Phone battery this requiring input voltage of 4.4V Max.
New equation 15.3VA (divided to) 4.4V = Ampere (directly handled by phone circuitry minus what ever power conversion losses).
DC-DC converters efficiency can usually be approximated as a constant between 75% and 95%.
In worst scenario 15.3VA with 75% efficiency this become 11.47VA

Now let’s see again VA output of all Samsung Fast chargers.
5V    2A   (true usable VA   8.5 ) EP-TA20EWE
5.3V 2A   (true usable VA   9.0 ) EP-TA10EBE
9V  1.76A (true usable VA  11.5 )EP-TA20EWE


I did buy two cables so to test them, one of those magic 2.4A super cables (but I did that mostly because I need a two meters long cable that is six feet long).
In my surprise from the supposedly premium flat 2.4A cables none of their manufacturer’s him deliver specific electrical specifications’, speaking of wire Gauge.

The second cable this is a regular Samsung micro B USB, also called as high speed micro, also called as USB 3.0 cable for Samsung phones. 

[Kiriakos GR]

UPDATE ...   

Micro USB soldering pads shown extremely fragile, and my connector this destroyed prior even using it.

An much better solution is this VLCP60901B converter, and I did find one locally (pricing within EU 1.70~3EUR).
Now I can use a pair of regular USB A connectors, and solder over them wires of much larger diameter 
   
Additionally I will say that I am going to use real high quality multimeter at verifying electrical parameters, but I will also use my KCX-017 so to find out how much energy my used phone battery this is able to hold.
First touch: USB gadget, LCD power monitor - Charger Tester KCX-017
   

[Kiriakos GR]

UPDATE ...   

a) It seems that I run out of luck with this VLCP60901B plug,  while the packaging does not mention anything, I discovered that this is an OTG plug = The phone recognized it and using it for connectivity with other USB devices but not about charging.

b) My first 5.3V charger that I did ordered from eBay, turned out as fake 5.0V, now ordered a second one from Spain and this will come later on.

If you are interested to see a fake Samsung EP-TA10EWE I did a tear-down and here is the link. 
http://www.ittsb.eu/forum/index.php?topic=1154.msg2790#msg2790

[Kiriakos GR]

This is another update relative to charging potentials.
Over time I did manage to get a special cable this is just 35cm long USB to micro USB 3.0,  this is high power cable that came accidentally when I shopped for one USB 3.0 real hub, and this cable came with it.

While I have build my own gadget of Volts/Ampere meter (USB charging monitor), and because my older USB capacity tester this had an accident (display smashed),  I did recently purchased the very fresh UNI-T UT658 USB capacity tester.
My new benchmarks this is another one confirmation of everything that I wrote so far.

Naturally when such capacity tester this is plugged directly to the charger and the charging cable this is powerful and sort, what you get this is highest possible voltage and current that phone circuit this can tolerate due minimal electrical losses at power transfer.       

New UNI-T UT658 USB capacity tester within 2017 Mini Review