Are 30Q 18650s genuine at ~42/43g? - UPDATE: all customers being refunded

Thanks. Is internal impedance the same as internal resistance?

For what it is worth, IR changes with temperature, state of charge, number of cycles and discharge rate for the test.

As with a lot of things, getting a number is just half of it. Understanding the parameters of the test and how those parameters affect the result is the other half.

Does internal impedance also change with those same parameters (temp, cycles, etc.)?

They don’t seem like a bad seller …
why won’t you tell us who they are ?

As I understand it…

Resistance is the “resistance” to a steady state amount of current flow

Impedance is “resistance” when current is pulsed or at some frequency or possibly including the “imaginary part” of current flow. (imaginary part in the mathematical sense, ie SQRT[–1] or i )

So, resistance and impedance can be thought of as the same thing but are technically not the same thing.

@pirate joe 22: I didn’t want to give them a bad name before giving them a chance to make good. They are Battery Junction dot com. I’m quite pleased and I wrote them a thank you note.

@prototype3a: thanks. I ordered a tester that says it can measure it.

Well, I did a drain test on one of the light “30Q” batteries that I got.

I drained one of them at 1A until it hit 3V. Here is the result. 1621 mAh (I assume the counter is in mAh). (I’m going to do a second one overnight at 0.5A)

Is my expectation of seeing nearly 3000 mAh off?

Not off, you should get near 3000mah, probably around 2800

I bought two 30Q cells from techaroundyou in Australia recently and they came with these markings:

INR18650-30Q
SAMSUNG SDI
6 KMT

On the can of cell 1:
R30Q
KAUA1
GAHC
CC
B14
W16

On the can of cell 2:
R30Q
KAUA1
GAHC
CC
B06
W23

Vapcell S4 Plus capacity tests:

Samsung 30Q6 18650 Cap Test #1 (2021-04-22)
Weight: 46g
Discharge 500mA
Max cell temp: 38C
Room temp: 16C
Capacity (mAh):
3046, 3083
Internal Resistance (mOhm):
26, 21

Samsung 30Q6 18650 Cap Test #2 (2021-04-23)
Weight: 46g
Discharge 1A
Max cell temp: 52C
Room temp: 17C
Capacity (mAh):
3094, 3124
Internal Resistance (mOhm):
23, 29

Personally, if you buy from a reliable source, you will likely not have to ever do all this leg work to check for authenticity. Generally speaking, if a particular battery is out of stock everywhere and one place seems to have big quantities in stock, this should be a huge red flag. Right now, Lithium Wholesale is very low on virtually every battery, so this should be an indication of the high demand.

I’ve only bought from liionwholesale.com and batteryjunction.com (this was the first time from batteryjunction). Now I’m going back and checking my liionwholesale.com batteries too.

I’m going to get that Vapcell S4 Plus charger you mentioned. You’re saying it can measure IR?

I’ve been using my Tenergy charger to test capacity by draining from “full”/4.20V to 3.00V at 1A.

Is that a pretty standard capacity test?

What’s an appropriate cutoff voltage to use when draining batteries?

My highest 30Q cell (from another order—used but not heavily) was 2400 mAh.

Most of the cells from this order seem to be around the 1600 mAh range.

1600mAh is wayyyyyy too low and even 2400mAh is too low for a genuine 30Q unless it’s been very heavily used. Are you reading 4.20v from the charger or a DMM? If it’s the charger have you confirmed it with a DMM? Perhaps your charger is not working well?

There’s an international battery shortage and a lot of re-wraps about. I’m UK based and only buy batteries from this lot. The guy running Fogstar has been tenacious since day one, batch testing and even visiting factories.

No affinity to, or gratuities from the seller, he just cares very much about the battery safety of Li-ion, particularly in our high draw multi cell vapes and lights.

DMM - what is a DMM? Sorry, I’m new to testing batteries.

Here’s a pic of the best test result:

This is using this charger to drain.

I just bought this tester but I haven’t made a circuit yet to actually hook it up. It came with no cables.

DMM is a digital multimeter which allows you to read voltage, current, and ohms. Your readings are so far off that my thinking is that your Tenergy is the the problem. Most counterfeits these days seem to do better than what you’re getting so confirming the starting voltage would be good.

Sorry to ask the obvious but you’re not charging the batteries using the LiFe setting are you? That would account for their low capacities. When you start the discharge does the display show 4.2v’s or 3.6v’s?

Never apologize for asking. I’m using a Nitecore D4 charger. It achieves 4.20V upon completion. Here’s a pic.

Ah, a multi meter. I didn’t know the “DMM” abbreviation. I happen to have one. This is after 6 hours out of the charger.

Well it’s definitely not the case that the batteries were discharged when they were less than fully charged. Too bad because that would have been an easy thing to fix :stuck_out_tongue: