High drain 21700 - Samsung 30T discharge test

[Hillhater]

..... Above i listed some comparison with Lygte's results and the difference is -0,15% to 1.5% (while my tester's official accuracy is 1%) so talking about some "constant 5-10% lower results due to measurement setup" is just making me advertising simple calculators here.

T. H. ...you wont be able to resolve these discrepancies if you cannot recognise them .
The Lygte 20A discharge trace is consistently 0.3 v (approx) higher than your equivalent results.
The same is true on the HB4/6 results.
0.3 v on a 3.0v measurement is a 10% discrepancy.
There is a real "clue" to the problem in the fact that your results are always lower than othe testers results ?

 

[thunderheart]

..... Above i listed some comparison with Lygte's results and the difference is -0,15% to 1.5% (while my tester's official accuracy is 1%) so talking about some "constant 5-10% lower results due to measurement setup" is just making me advertising simple calculators here.

The Lygte 20A discharge trace is consistently 0.3 v (approx) higher than your equivalent results.

Maybe i'm the stupid but please tell me how do you manage to trace 0.3v difference on that low-res images??? (no sarcasm)
P.S. I've compared Lygte's results at 5A with mine for 3 cells and you could see that the difference is as low as could be when re-testing the same cell on the same equipment in the same conditions and my results are sometimes lower, sometimes higher. I compared the energy in Wh, not the capacity to eliminate question about voltage drop. I didn't compare at 10A, 15A and 20A because there was no data on energy measured at those discharge rates on Lygte's site. If i missed it - please show me. Thanks in advance.

 

[Hillhater]

The images have voltage scale incriments of 0.1 v so seeing 0.3 v is easy, 0.01 v is possible to estimate
Keeping this simple , focus on the 30T, 20A results and forget total capacity for now.
Pick a SoC , like 1000mAh and read the recorded voltage at that point ...
Lygte = 3.60v. Yours = 3.33v
And at 2000 mAh ,...Lygte = 3.33, Yours = 3.05v
The difference is less at lower amperage discharge...and that gives another clue as to possible causes !

 

[liveforphysics]

The images have voltage scale incriments of 0.1 v so seeing 0.3 v is easy, 0.01 v is possible to estimate
Keeping this simple , focus on the 20A results and forget total capacity for now.
Pick a SoC , like 1000mAh and read the recorded voltage at that point ...
Lygte = 3.60v. Yours = 3.33v
And at 2000 mAh ,...Lygte = 3.33, Yours = 3.05v
The difference is less at lower amperage discharge...and that gives another clue as to possible causes !

Thank you for being so clear to help him.

I have a good feeling his next fixture will be offer lower errror bars. He is a minor difference in setup effort away from useful high current cell test data.

 

[madin88]

It seems as if you still don't understand that your setup measures 5-10% lower volt and Wh compared to others

Samsung 30T at 5A:
Lygte's result: 10,818Wh
My result: 10,72Wh
Difference: 0,90%
For 10A, 15A and 20A discharge rates there is no energy mentioned to compare.

LG HB6 at 5A:
Lygte's result: 5173mWh
My result: 5093mWh
Difference: 1,55%

Samsung 48G at 5A:
Lygte's result: 16,116Wh
My result:16,14Wh
Difference: -0,15%
Oops... My setup didn't measure lower Wh... Sorry)))

Start by learning basic maths...

Lygte discharge to 2,8V while you stop discharging at 2,5V
Start by learning how to read a diagram correct...

 

[thunderheart]

Even if compare, say, 30T's result at 5A rate down to 2.5V and 2.8V the diffrence in capacity would be 0.988% and in energy - 0.709% (3006mAh/10641mWh @ 2.8V vs 3036mAh/10717mWh @ 2.5V)

0.7% in energy
I hope that 0.7% will make you happy

 

[madin88]

0.7% in energy
I hope that 0.7% will make you happy

At least it seems you understood that above comparsions are not exactly true because of the different cut off voltage.
That makes me already happy

Your setup measures already lower voltage at 5A and now think further what happens at 20A or even higher discharge currents.
Wh are linear with voltage so the losses square with the current.

 

[thunderheart]

)))))))))))))))))))))))))))))) You make me happy, dude)))))))))) I like you, definitely!))))))))

 

[larsb]

Now that the love is in the air i must ask: will the 10A and 15A tests of the Samsung 30T be redone?

All tests are questionable even if you've done your best until you nail a root cause.

 

[docware]

Hello everybody,

you may be interested in the fact, that lygte has changed the clamp for battery testing some time ago.

https://lygte-info.dk/info/batteryTestImprovement%20UK.html

 

[pwd]

I'm been keeping tabs on the 40T and 30T cells. I've just noticed that the price has dropped again for the 30T. This site has it for $5.25 USD per cell for 50 +:

https://www.18650batterystore.com/21700-p/samsung-30t.htm

$6.00 USD per cell for 50 + here:
https://www.imrbatteries.com/samsung-30t-21700-3000mah-35a-battery/