Recent content by bellfador

This are different tests. First is test for internal resistance ( around 7000s), second is pulse mode tests (around 4000s).

Another 2 cell from LiPo Graphene 1.5Ah 65C pack is added. After 2 cycles with +1A / -1A and 3 cycles with +2.3A / -4A: Cell2: 1487 mAh from SkyRC B6 @1A; 1453 mAh from the battery tester 0.9A / 8A; Cell3: 1490 mAh from SkyRC B6 @1A; 1465 mAh from the battery tester...

I will try to do that soon.

My DCIR measure pulse is 10 seconds with 8A. This is near to C/100 for 2.2Ah cell. Maybe you mean my ACIR test pulse - 1.05 ms with 8A or C/ 7 500 000 for 2.2Ah cell.

What kind of information gives C/200 DCIR ? No load voltage drop when cell lose some of its capacity. This is not happening bеcаuse of the internal resistance.

LiPo Graphene 1.5Ah 65C is added. After 2 cycles with +1A / -1A and 3 cycles with +2.3A / -4A: 1492 mAh from SkyRC B6 @1A; 1467 mAh from the battery tester 0.9A / 8A; Pulse test: 4.1V - 3.4V C= 1265 mAh; E= 17379 J; pulse counter=58; Weight of one naked cell: 42.71 g

A123 26650m1b is added. 2530 mAh from SkyRC B6 @1A; 2470 mAh from the battery tester 0.9A / 8A; Pulse test: C= 2245 mAh; E= 25819 J; pulse counter=101; Weight: 75.55 g

VTC5A is added. 2460 mAh from SkyRC B6 @1A; 2400 mAh from the battery tester 0.9A / 8A; Pulse test: C= 2029 mAh; E= 26111 J; pulse counter= 89; Weight: 47.34 g

Yes, mOhm*gram is correct.

Simple example: One cell with 2Ah, 20 mOhm have 40 mOhm /Ah because when are connected two cell in parallel each with 1Ah, 40 mOhm summary capacitance will be 2Ah and internal resistance - 20 mOhm. ...Resistors in paralel: R12 = (R1*R2) / (R1+R2).

Here are my testings of 30Q. https://endless-sphere.com/forums/viewtopic.php?f=14&t=73701 I see some differences, but is close to DCIR.

How is measured the internal resistance?

The charger measure only AC internal resistence and also the measurement is inaccurately. In your case the voltage sag is linked to DC internal resistence and DCIR > ACIR. Your calculation is wrong . 8 mOhm for 5Ah is equal to 40 mOhm/Ah.

Easy calcs... 3S 1300 mAh turnigy nano 25-50C weight 139g, or 46.3g per cell. Dc internal resistence will be approximaly 7.7 mOhm or 166 mOhm /g and 37 mOhm/Wh. VTC5A have 377 mOhm /g and 152 mOhm/ Wh. Soon I will make a test on some lipo and I can tell with sure.