Found a Quality Battery Resistance Tester

That’s exactly where I ordered, too. So, I‘m confident to get the new version, too. Unfortunately, the shipping address in my Aliexpress order is missing the country even though it was correctly assigned in my account. Maybe just an displaying error.

I finally got 4 x 30Q button tops from Bangood today after waiting for over two months. They all test at 12.0 IR with the SM8124A tester so they are real samsungs!

Mine finally arrived today.

It’s the newer 4 prong model.

Someone said the measurements you get with this meter are not the same you get with your Battery Charger / Testers.

Yeah, I found that to be very true.

How would you convert between the two in order to determine if your charger/tester gives readings consistent with the SM8124A?

They measure differently so there probably is not a reliable conversion method. The SM8124A should give results close to the battery data sheets which use the same method as this meter to determine resistance which is a good start to see if you got originals or fakes. What I have found so far is that if I add 60% to SM8124A readings of protected cells, they match up with the battery charger IR readings. So far, different types of protected cells from different companies still seem to be 60% more or close enough across the board but for unprotected cells like the Samsung 30Qs, the difference was 200% higher with the battery charger than this tester.

Good stuff there. Thanks!

Did you build a rig for this purpose?
Any pics?

I did build something like this before, but I used bypassed spring holders instead of brass buttons. That was very hard to do though, unlike the more refined method I presented to you guys.

However, now that I have made my Beryllium copper springs, I am going to do one that is much simpler to do for everybody, and is much easier to set up.

Awesome. I’d like to make one. But since you know what you’re doing I’ll wait to see how you did it.

When you decide to use your new springs to build your new tester, it won't test IR the same as the SM8124A will it, but instead the second method you mentioned above to give real IR readings?

I have doubts about this device.
I need to do some tests using the DC Calculation method to verify but I’m getting results that aren’t consistent.

That said, I removed the cable separator because the leads were too short to get to both sides of my batteries.
Does anyone know if there is some magic in that simple plastic separator that could affect the readings?

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

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...

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

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.

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

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.).

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

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

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.

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