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

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CNCman
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Always weigh your batteries and check the sellers advertised weight BEFORE buying, if no weight is stated, do not buy.
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I only buy 30Q’s from a few stores that Guarantee Authenticity, NEVER— Ebay, BanGood, AliExpress, or similar stores.
Good batteries are not cheaply priced.
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https://www.imrbatteries.com/samsung-30q-18650-3000mah-15a-battery/
https://liionwholesale.com/collections/batteries
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d_t_a
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fogus wrote:
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.

I’m not an expert here, but I measured capacity differs depending on the manufacturer and the specific battery model (they are usually listed in the datasheet for that specific battery)…

But based on my limited experience reading several battery datasheets, for 18650s, it’s usually 0.2C (1/5th of the capacity), ie. discharge at 1/5th the nominal capacity.
So for a 3000mAh battery, discharge it at 3000/5 = 0.6Amp, and it seems for many 18650s, the end-voltage is 2.50v, to get the manufacturer rated capacity (I see a few 18650s that have an end-discharge voltage of 2.65v or 2.75v, and a very few that even have and end-discharge voltage of 2.00v — I think the LG HG2 has this).

But for simplicity’s sake, when I check an 18650 battery’s capacity, I discharge at 0.5A down to 2.50v (can program the setting in the SkyRC MC3000 analyzing charger).

Discharging to 3.00v will probably lose a small amount of capacity only though – perhaps 100mAh more or less (compared to discharging down to 2.50v). However, if it’s a low-drain cell, then there may be a more noticeable difference discharging at 1A compared to discharging at a lower 0.5A. But for most high-drain and good medium drain cells, the capacity tested at 1A vs at 0.5A is minimal (as per my experience, discharging using my MC3000 charger)..

fogus
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Since my purpose is comparing one of my cells to another and to itself over time, I think I will standardize on the 1A discharge to 3.00V, and I’ll simply expect to be under the manufacturer’s rating by a bit. The rating should give me a decent idea of the cell’s performance in a flashlight. 1A also allows me to test twice as fast as 0.5A Smile

JaredM
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Be aware that most every cheap discharger is only a two point connection and this will terminate the discharge prematurely due to IR losses in the wires and contacts. Using higher currents will exacerbate this effect.

https://fundrazr.com/osturaband

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CR888
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My button top 30q’s all way 46.75gram give or take a few 100’s of a gram. If I was the OP I’d take the clear & pink wrapper off a cell to see if Samsung’s unique codes are underneath. Given all his cells are 42g. Damn mine field the battery market. I think unless you can do current discharge tests to see what amps they can sustain I’d first examine them phisically.

CR888

JaredM
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Oh. Forgot to mention genuine samsungs have a stamping near the rim on the bottom the can. In my experience, 30Qs always had a greek alpha. Others like 20r and 25r had things like Y4 or stuff like that. The stamping is faint and small, and you need to remove the portion of the pink wrapper that extends over the edge by ~3mm to reveal it.

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

Yes. It may not be super accurate. IR is used by the charger to determine the current to use.

fogus
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S4 plus arrived today (yes, that fast). Will have results in the morning.

fogus
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Results:

My existing 30Q cells bought from various places are averaging 2900 < X < 3000 mAh per the S4’s capacity test (essentially perfect in my book for being a few years old). mOhm ratings from 56 to 105. Not sure what that means yet.

The new “30Q” cells which were fully refunded are scoring 1900 < X < 2100 mAh with (roughly) 35 – 42 mOhm. I don’t know much about what the mOhm rating means yet.

CR888
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fogus wrote:
Results:

My existing 30Q cells bought from various places are averaging 2900 < X < 3000 mAh per the S4’s capacity test (essentially perfect in my book for being a few years old). mOhm ratings from 56 to 105. Not sure what that means yet.

The new “30Q” cells which were fully refunded are scoring 1900 < X < 2100 mAh with (roughly) 35 – 42 mOhm. I don’t know much about what the mOhm rating means yet.


Have you removed a wrapper to see if genuine?

CR888

TimMc
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fogus wrote:
I don’t know much about what the mOhm rating means yet.

mOhms is the unit of measurement that’s being used for Internal Resistance of the cell.

A lower value is better (10-15 mOhms etc).

https://batteryuniversity.com/learn/article/rising_internal_resistance

https://batteryuniversity.com/learn/article/how_to_measure_internal_resi...

ggf31416
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Having the correct weight is no proof of authenticity but being too light or too heavy is a sure sign that the chemical composition is different so it cannot be genuine.

mortuus
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well i mean a legit samsung 30q battey is like 5$ or so.. hardly expensive but always adviced to check what u buy.

...where Frugal meets with Flashlight!

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