Found a Quality Battery Resistance Tester

Off-topic Chatter
85

Today, I tested some new cells with my SM8124A. This is the impedance I measured:

Format Name Impedance (mΩ)
21700 Samsung 30T 6.0
21700 Samsung 40T 7.4
21700 Samsung 50E 22.0
21700 Sofirn 4.000mAh 13.6
20700 Acebeam 4.250mAh 21.6
18650 Sony VTC6 11.8
18650 Samsung 25R 12.2
18650 Samsung 30Q 12.5
18650 Imalent MRB186-P30 19.3
18650 Wuben 2.600mAh 23.4
18650 Sofirn 2.600mAh 41.9
18650 Sofirn 3.000mAh 45.2
18650 Xanes 2.600mAh 45.3

86

Thanks for sharing! That would be a useful baseline reference.

I only have a few of those batteries from your list. I don't have the SM8124A, but instead got the YR1030. I wonder how different the measurements taken by the SM8124A compared to the YR1030...

87

Nice chart thanks. My Samsung 30Q from Illumn read 10 and 30Q from Banggood read 12 so close enough.

88

FWIW, it takes a lot of patience and two calm hands to get useful values with the SM8124A.
Especially, with button top batteries it’s quite a nightmare to align the probe correctly in order to get useful information. :person_facepalming:
I guess it’s the same with the YR1030 from Vapcell. They had it for a very decent price on Black Friday. Unfortunately, I forgot to buy one as I would have liked to verify my values with a second device.

89

Major PITA to align the probes on button tops. I use my desk lamp with the magnifying glass otherwise it takes too long.

90

LOL…“PITA”…that’s exactly what it feels like. :+1:
Later on, I try to amend my chart with values I took from my 26650s (Shockli 5.500mhAh, Keeppower 6.000mAh, Dolidada Fake PLB-55-As, Thrunite 5.000mAh, etc.).

91

I have now added some more batteries. All cells were measured in new, unused condition. However, the 26650 cells I bought had some differences between them.

Format Name Type PCB Impedance (mΩ)
21700 Samsung 30T FT 6.0
21700 Samsung 40T FT 7.4
21700 Sofirn 4.000mAh FT 13.6
21700 Efest 5.000mAh FT 20.6
21700 Samsung 50E FT 22.0
21700 Acebeam 5.000mAh BT x 30.4
20700 Acebeam 4.250mAh BT x 21.6
26650 Shockli 5.500mAh FT 12.5 - 12.6
26650 Shockli 5.500mAh BT 12.7 - 13.0
26650 Keeppower 6.000mAh FT 16.4 - 17.5
26650 Keeppower 6.000mAh FT x 31.5 - 33.2
18650 Sony VTC6 FT 11.8
18650 Samsung 25R FT 12.2
18650 Samsung 30Q FT 12.5
18650 Imalent MRB186-P30 BT x 19.3
18650 Wuben 2.600mAh FT 23.4
18650 Sofirn 2.600mAh BT x 41.9
18650 Sofirn 3.000mAh BT x 45.2
18650 Xanes 2.600mAh BT x 45.3

92

Here's my list so far. Need to find the data sheet but I think the 30Q's from ff are out of spec!

93

Yeah. That Illumn cell is either a beast, or something is wrong.

I don’t think the FF cell is bad though. The maximum internal resistance of a 30Q with AC testing is 26mOhms.

94

Thanks, saves me looking for the sheet! Tested all the illumn 30Q's too many times and always 9.

95

Thanks for mentioning that 30Qs from Fireflies.

I also got 3pcs 30Qs bundled with the Fireflies ROT66 (I am unable to purchase 30Qs without flashlights [bare batteries from any foreign online store cannot ship to my country, except if inside a flashlight], so all my 30Qs are only purchased when I purchase a flashlight, either the “BLF A6+30Q” or the “S42+30Q” bundle from BG).

The 30Qs I got from BG have lower IR than the 30Q I got from Fireflies… Will do some measurements again. Forgot the figures but there are noticeably higher IR, measured either using the MC3000’s IR test or with the YR1030 battery resistance tester.

96

I think it was mentioned somewhere before that battery manufacturers use the AC method to grade the cells and then sort them depending on the results. It seems there may be A-B-C and possibly even D grade cells of the same make that are then sold off accordingly.

97

Update (see highlighted in red).

I am pretty much amazed about the extreme low impedance of the Tesla cell (Sanyo NCR21700A 5.000mAh 15A).

Format Name Type PCB Impedance (mΩ)
21700 Samsung 30T FT 6.0
21700 Samsung 40T FT 7.4
21700 Sanyo NCR21700A ("Tesla") FT 11.2
21700 Sofirn 4.000mAh (w ring)
 FT 13.5
21700 Sofirn 4.000mAh (w/o ring)
 FT 13.6
21700 Efest 5.000mAh FT 20.6
21700 Samsung 50E FT 22.0
21700 Acebeam 5.000mAh BT x 30.4
20700 Acebeam 4.250mAh BT x 21.6
26650 Shockli 5.500mAh FT 12.5 - 12.6
26650 Shockli 5.500mAh BT 12.7 - 13.0
26650 Keeppower 6.000mAh FT 16.4 - 17.5
26650 Keeppower 6.000mAh FT x 31.5 - 33.2
18650 Sony VTC6 FT 11.8
18650 Samsung 25R FT 12.2
18650 Samsung 30Q FT 12.5
18650 JetBeam HR26 2.600mAh BT x 16.5
18650 Imalent MRB186-P30 BT x 19.3
18650 Wuben 2.600mAh FT 23.4
18650 Sofirn 2.600mAh BT x 41.9
18650 Sofirn 3.000mAh BT x 45.2
18650 Xanes 2.600mAh BT x 45.3

Obviously, Sofirn rewraps cells of different manufacturers as can be seen on my comparison of two Sofirn 21700 4.000mAh batteries. Both batteries were part of two C8F 21700 flashlights. The one with the recessed ring in the bottom seems to be a Lishen 2170SA. Fortunately, both the one with ring and the one without seem to have similar specs in terms of capacity and performance.

98

Updated my list with legit Samsung 40T's that I got today. Inserted them in my two E07's and they shine seriously bright.

99

I'm also looking for my first tester. I choose between YR1035+, SM8124A, Volcraft BT-501 - which is better ?

100

For 18650 users, charging with Peacefair PZEM-010 four-point tester

101

I have been pretty happy with my YR1035+. I chose it because it displays more digits. It also has a backlit display and a rechargeable battery inside. I had it for a couple of months, but I only charged it once.

It displays up to 4 decimal places in voltages for Li-Ion batteries, 2 decimal places for internal resistance in mOhm range. I cannot tell how accurate the numbers are, but the numbers are at least very consistent when I measure the same battery multiple times.

102

YAOREA YR2050

103

Based on the product description, the YR2050 only tests resistance and cannot be used to test batteries (which have voltage)

104

Minor correction its the Lishen LR2170LA