Sony 18650VTC5 cells FAKE or REAL?

johnnyz

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Hi guys

Im hoping that there are guys here who know how to tell the difference (besides testing capacity and resistance) between REAL Sony VTC5 cells and fake ones. I am meeting someone who claims he has 1000's of them in stock and at $4.00 each or $3.50 if I buy in lots of 500, cheap. Any help would be appreciated.

sony.jpg

John
 
Thanks for the response.

I need something to go by on a visual basis, in order to test as it is an hour away. I can bring my Imax and test capacity, and also fully charge, see the voltage drop across a known resistor value and calculate resistance, but that takes time...
 
I don’t see no visible red-flag that screams it’s a fake in my opinion.
But it could be some really well copied fakes. As he said, the only reliable way to tell is to test.

From the code labelling, I understand this

SE US18650VTC5 CS

SE : Sony Energytec
US 18650VTC5 : VTC5 model, 18650 size-format
CS : ???

G 1101835YB16P

G : Manufactured at the Sony Energytec (Singapore) plant (K= Koriyama ; T = Tochigi)
1101835 : ????
YB16P : Date of Manufacture: February 16th, 2016 ; electode history "P".

or in details with Sony's coding:
Year "Y" : 2016 ( A= 1992 ; […] ; L = 2003 ; M = 2004 ; N = 2005 ; O = 2006 ; P = 2007 ; Q = 2008 ; R = 2009 ; S = 2010 ; T = 2011 ; U = 2012 ; V = 2013 ; W = 2014 ; X = 2015 ; Y = 2016 ; Z = 2017)
Month "B" : February (A = January ; B = February ; C = March ; D = April ; E = May ; F = June ; G = July ; H = August ; I = September ; J = October ; K = November ; L = December)
Day "16" : 2016
"P" : Electrode history

Here's one of my VTC4...
VTC4.jpg

Matador
 
johnnyz said:
Thanks for the response.

I need something to go by on a visual basis, in order to test as it is an hour away. I can bring my Imax and test capacity, and also fully charge, see the voltage drop across a known resistor value and calculate resistance, but that takes time...

Best test IMHO is not for capacity but for ability to give a lot of power.... That, you cannot fake it (for exemple any crappy laptop 2200 mAh can match the capacity of one of my 2100 mAh Sony VTC4. But only the VTC4 can give 30A of current, while the laptop cell stuggles at 5 amps).

If you draw 10Amps from a cell and it drops 1 volt... it's a fake (with high internal resistance). Even 0.6V is sketchy for a VTC5 cell.

VTC5 shoud be around 30-35 milliohm DC internal resistance at the very most. I'm not sure the exact value... Little more DC resistance than the VTC4 but more capacity.
So if you pull 10Amps for 3 to 10 seconds or so, the voltage should not drop more than 0.30 to 0.40 volts difference from initial (no-load) voltage.
For example, pull 10Amps (which VTC5 can easily take with no harm at all) and from a full 4.20V charge, it should not be under 3.80 Volts (of course if you leave it there for long, voltage will go down not only because of internal resistance-induced voltage drop, but also because you're just physiologically discharging the cell.... A 1 to 3 second test is more than enough IMHO.... You need a load resistor and a voltmeter to test. I'd use a resistor that's between 0.3 and 0.5 ohms (i mean a big one good for AT LEAST 100W or more.... check ebay).

Do it from a cell charged at 3.6 V and it should not drop lower than 3.30 or 3.25V
If it's a fake made out of laptop cells, It will go down 0.8 to 1.0 volts at 10A....
That's a good indication IMHO.
Sony US18650VTC5 (Rated 20A, 2600 mAh).jpg
Remember, If you pull 10A from that 2600 mAh cells, you will dischare it completely from 4.20V to 3.00V in just 15 minutes or so. So only test for a few seconds at a time in order to account only for the real instant voltage drop (reflects the DC internal resistance) while minimising the effect of normal discharging on voltage readings.
Matador
 
This is the kind of test I did on my VTC4 as an exemple....
The cells I got were around 20.9 milliohm DC internal resistance (VTC4 are very low resistance, even a little more so than the VTC5 but still very close).
You can see I used different 100W resistors as dummy loads...
I also simultanously measured voltage and amps.
My cells were initially close to 3.964 volts (float voltage).

I tried different resistors (big 100W ones.... otherwise they burn) : 0.5 ohm, 1 ohm, 2 ohm, 4 ohm
At 0.5 ohms, I could pull close to 7 amps ! and that would drop voltage from 3.964 to 3.818 V
Sans titre-4.jpg

See what I mean ?
If it drops from 4.20 Volts to 3.0 Volts at 10A in just a few seconds, it's obviously a fake.
If it only drops from 4.20 Volts to 3.80 or 3.90 V at 10A for a few second with the load resistor across the cell, it's looking good.
Remember.... don't leave it too tong of you will just discharge the cell... and voltage will go down with discharge state.
On a fully charged (4.20V) VTC5 cell, at 10 A, the voltage at 10A load shoud be : 3.7 volts after 3 minutes discharge ; 3.5 Volts after 6 minutes discharge ; 3.35 volts after 9 minutes discharge ; 3.2 Volts after 12 minutes discharge ; 2.8 volts after 15 minutes.
That's if you maintain the load at 10A constant the whole time (in reality, the amp load will go down with the voltage a bit).... Upon removing the load resistor, the 2.8V shoud jump back to 3.25V no-load (study that discharge curve to understand... see my preceding reply above).


In brief, I call this the "Load-test" method for spotting fake "High Power", "High Drain" or "High amperage" cells.
The VTC5 is one of those "High Power" cells....

For testing Low power (but high capacity) cells (ex : cells rated for 5amps max), than I suppose checking capacity if a better way to spot fake, as opposed to doing a "Load-test".
Let's say you test a high capacity Panasonic NCRB cell that's good for 5 amp current or so but can give 3300 mAh capacity at 0.1C, well the fake or cheap laptop cell can also give that 5 amp current, but it will only probably yeild 2200 to 2600 mAh capacity, in which case, testing for capacity is the best way to tell if it's a fake or a real genuine Panasonic NCRB cell.

Matador
 
Unlike LG Chem and a few other brands, Sony rarely ever sells to the public wholesalers/distributors and stopped making VTC5 cells at least 2 years ago.

To date, if it didn't come out of a tool pack, or didn't come as a sample cell from Sony, it's very likely fake (with exceptions of at least a couple vape shops/dealers who really have a Sony cell buying setup.)
 
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