Latest release Vapcell 21700 5600mah 12.5A battery

That doesn’t sound good.

I ordered a few pieces of K64 last April 3. Vapcell/AliExpress gave me a tracking number on April 8. But that tracking number doesn’t give any update at all using multiple tracking sites (17track, postal.ninja, track24, etc. sites) It’s been over 1 month since those K64 have been shipped out, so if they’ll discharge to low voltage, in case I receive the package, then several of them may have self-discharged to low voltages…

Unless you have the ability to test your batteries, I would only buy from a trusted retailer/supplier for now. There’s only 1 US retailer I would buy Vapcells from because they perform their own QC and their QC is at a higher standard than Vapcells. I bought the F14 from them. I don’t have a need for the K64 unless I buy another flashlight and I don’t really want to.

Sad state of affairs.

So obviously this sounds like a more extreme case of self discharge but what is an acceptable level of discharge anyways? I suspect re-wrappers don’t promise anything but do OEM’s even publish a spec? You see it in NiMH for instance X% battery life after 6 months in storage. Higher drain batteries tending to have shorter storage life for that chemistry anyways.

Why do people buy re-wrapped cells not knowing what cell is underneath?

The only good 26650 cells i’ve heard of are all based on the PLB55A cells.
I haven’t heard of a cell from PLB greater than 5500mah, and they are like the ONLY manufacturer of 26650s.
There’s no way Vapcell has a “new” cell that gets 6400mah….UNLESS they are “binning” the batteries that test that high, which doesn’t sound like that’s the case.
Also, no response from Vapcell, not a good look for Vapcell….
But hey, they pulled ALL the K64 listings form Aliexpress to prevent people from buying them while they re-evaluate their QC.

Their gold 5300mah G53 26650s I’m pretty sure are based on the PLB55-A, so buy those if you want a pretty looking 26650…

26650s are getting obsolete with very high quality 21700s on the market from Samsung, LG, Sony, Molicel, Panasonic (Tesla), so maybe its time to move on?

Did you try to ask Vapcell's customer service what freight carrier they were using? Mine are being shipped by Meest Group, probably via ship from Shenzhen, CN via Rotterdam, NL and then further to Germany. I ordered my six K64 batteries on March 27, 2021, i.e. 45 days ago. According to tracking (which also did not work for several weeks) my order it is still being processed in Guangzhou, CN. I do not expect it to arrive within another 45 days. :-D So, for lithium-ion batteries it seems to have become really painful handling logistics on a reasonable price level.

Try to look at it from a positive side: If those cells you ordered arrive with ultra-low voltages, you will know immediately these are defective. Otherwise it probably takes to pay some more attention (measure resistance/impedance, charge to a set level and observe voltage sag, etc.).

These are intruiging questions that I would also like to see answered. So far, except for one Lishen LR2170SA and one Sofirn DLG 18650 battery (probably just bad luck?) none of my batteries, regardless if these were cheap Dolidadas or high priced Samsungs, have indicated any significant voltage sagging over the course of 3 years. I mean, I charge them to let's say 4.16V. Some days later they settle at let's say 4.12V and that's it. 6 months or 12 months later - still 4.12V.

Probably working with a factory to produce these K64 solely for them which is where the QC issue might come from.

Here’s hoping Hank redesigns the D4sV2 for a 21700 battery.

I agree, 26650s are nearly obsolete when compared to 21700. But 26800 becomes interesting again. Enough capacity differential and creates good ergonomics for an single cell light.

The future isn’t looking good for Vapcell if they don’t change their act. IMO the H10 and 10440 are their only cells that are relevant. The white 16340 was nice too, but that’s gone now. The only time I’m going to buy a non-Japanese or Korean cell is for uncommon sizes like these mentioned.

Which store would that be? My Vapcell K30’s had plastic wrap making it impossible for 18650BS to check

I don’t think you can get 6400mAh from regular 26650 cells, no matter how you bin them, so it has to be a new cell. Not all K64 and K31 cells have the self-discharge issues, so it looks like something that can be improved rather than an inherent issue with the cells.

Hello, members of the forum. I’ve been busy recently and didn’t reply to the information in time

Yes. Vapcell k64 battery has the problem of self discharge. At present, vapcell company has stopped selling. We’re already dealing with this battery technology. If you place an order for vapcell k64, you can apply for a refund of the full amount to Ali-express. The customer staff will process the refund request as soon as possible

At present, among the batteries sold in vapcell warehouse, Only k64 receives a large proportion of quality complaints. OOccasionally, we receive a very small proportion of quality complaints, among which some quality problems are also caused by the improper use of consumers,most of the vapcell batteries have no self discharge quality problem. Please don’t worry about the quality problems of all vapcell batteries.

K64 is too fast delivery, delivery detection voltage is normal, did not stand more than a month to test, resulting in quality problem. k64 is a new battery technology of 26650, which needs enough time to test. Last time, there was a customer feedback on the quality of K30 cell, which has been improved. At present, the battery performance is very stable.

K64 battery is still undergoing technical improvement. If it can pass the tests, it will continue to be sold. It is expected to take several months.

Vapcell is committed to developing high-tech battery products. Through these quality problems, we will learn from them and strengthen quality control. let every consumer receive high quality batteries

Thank you for your support to vapcell

Thank you

Ahh, thanks Dennis! I'll apply for the refund.

Guys, what do you do with cells having a considerable self-discharge rate? Safe to keep on using or better put them into the trash?

Well, the way they are acting may not be totally useless, just dunno how safe.

From Mooch’s Facebook

“If you are not sure you have bad K64 cells then charge them fully and let them sit for a day to let their voltages settle. After a day’s rest accurately measure and write down their voltages. Then store them in a non-conductive case at room temperature for at least a week and then re-measure their voltages. If any have dropped by more than a few thousandths of a volt then IMO they are self-discharging too fast and you should get a refund.”

If they’re dropping too quickly I’d bin them, especially since this is a new untested cell

I fear an internal short while charging them up. I just found this on Battery University:

„Li-ion self-discharges about 5 percent in the first 24 hours and then loses 1–2 percent per month; the protection circuit adds another 3 percent per month. A faulty separator can lead to elevated self-discharge that could develop into a current path, generating heat and, in an extreme case, initiate a thermal breakdown.“

Source: https://batteryuniversity.com/learn/article/elevating_self_discharge

Thanks. I guess it’s best to first separate cells with deep discharge state (< 2.5V) from those that still show a reasonable voltage (> 2.5V and < 4.2V). I would say the deep discharged ones should better be disposed right away without any attempts of charging.

Maybe I am interpreting that statement incorrectly, but 5% of 4.20 volts is 0.21 volts and I would be concerned if any of my Li-ion batteries self-discharged to 3.99 volts within 24 hours after being fully charged to 4.20 volts.

Your statement is not accurate. You cant just do 4.2*.05 for charge percent. See our very own HKJ’s write up

In any case settling down 5% from 4.2 for a large battery like this would still be around 4.1x

Thanks for the correction, what I forgot to take into account is realizing that the discharged voltage of Li-ion is ~2.80 volts, therefor:


4.20 volts - 2.80 volts = 1.40 volts
5% of 1.40 volt = 0.07 volts
4.20 volts - 0.07 volts = 4.13 volts


This self-discharge voltage within 24 hours, seems more reasonable.

This goes to show that you shouldn’t rush QC, because QC always takes longer than the rest of the company wants, as they see it as “preventing them from making money”, when its more like “assuring they can make money” off of the product.

Also not right since that implies that at 3V there is still 15% battery left. 2.8+0.07*3 = 3.01V

Most of the capacity comes from the higher voltages and not much left when the battery is low voltage. Either way, it would be nice if some data sheet spec exists per battery to say “expect is to maintain >= this voltage after 1 month, 6 months, 12 months” or similar.