Latest release Vapcell 21700 5600mah 12.5A battery

They don’t offer any alternative for me, only $6 option.

Interesting, I had a bunch of Vapecells arrive yesterday 2 of which were K64’s and they were perfectly ‘storage’ charged. 3.76v & 3.84v. I drained one down to 2.8v then charged it and got well over 6k mAh’s like 6250mAh. The vapecelll INR21700 4200mAh cells which are the Mollicel 4200 30A continuous discharge had a clear wrapping over the cells which I thought was clever protecting the contacts. But so far I like those K64 cells and the little 18350’s with 1400mAh tested well (T14), I measured over 1400mah when charging but are only 4A. But to be honest I’ve been pretty happy with Sofirns cells like their 4K/5K 21700 and I have a bunch of their 18650’s which have been decent. Much cheaper too.

Having unequal storage voltage shows there’s still a voltage instability problem. Every single Samsung, Panasonic, Sony, and Molicel have been exactly the same voltage across 500+ cells.

Roughly 40 of the 120pcs Vapcell K30 that were okay in my order were a solid 3.71v, the other 80pcs were 3.68v+, and the remaining were even as low as 1.78v (got a refund on 20pcs of the worst)

I guess the best we can do is:

  1. Measure internal resistance (requires some equipment to compare between resting voltage and voltage under load) and compare against other batteries of the same make and model and/or against the datasheet (if there was one available).
  2. Measure internal impedance (requires an impedance meter like Vapcell YR1030/1035 or SM8124A) and compare against other batteries of the same make and model.
  3. Charge the battery to a certain value (maybe "storage voltage" around 3.6V - 3.8V would be best?) and observe any sagging in resting voltage over the course of let's say 14 days or 30 days. Cells of good quality should keep their voltage rocksolidly stable. Those with a quickly dropping voltage may have some issues concerning their electrodes inside but I can only guess.
  4. Batteries below a certain resting voltage (IDK, 3.0V or maybe lower than this) should not be charged at all and considered as defective?

I wonder how safe it is to run lithium-ion batteries with a high self-discharge rate. I know that some chemistries have a rather high self-discharge rate but I only saw these in NiCd or NiMH cells before. A lithium-ion battery is a whole different thing, I guess.

BTW, I have (among other batteries) six K64 batteries incoming. They are probably still en route to Europe or being checked by customs (who knows). I will be happy to carry out steps 2 and 3 and report about their status as soon they have arrived.

Do you mean F14? I can’t find a T14

Hopefully Vapcell reworks the K64. I don’t need it but I want it.

Wow the K64 is incredible! Thanks for sharing!

Yes they’re Green, F14 is right.

Any idea where they were purchased?

If I am not mistaken they were bought from Vapcell‘s AliExpress store.

K64 sucks… After ~two weeks of non-use have 2.04V and 0.20V!!! :person_facepalming:

Sitting inside or outside a device?

Too bad. I had high hopes for this cell.

It certainly sounded decent, but unstable voltage isn’t good. First on my K30’s and now hearing this, their QC sounds like a real issue at the moment

Outside

Are you able to get a refund?

I hope so, but I just opened a dispute :smiley:

Oh boy, might have missed this since I've not been keeping track of usage and level. I'll check mine same way, assuming your non-use means you had them sitting loose, not in a flashlight or charger.

I used mine in testing, not sure when, at least couple days ago. They read 3.92V and 4.18V now, and probably not re-charged after use. Recorded the values and time now - will see how they do over the next week on the shelf.

So far after 54 hours, 1 cell no change at 4.18V, the other dropped from 3.92V to 3.71V. Not sure how much usage each got though - wasn't keeping track, but neither got much usage except for high current drain in tests. I'll continue to monitor these 2.

Seems like I may have the same problem maba has above, but for me in just one cell for now.

This is bad news, can't trust these K64's . They disappear from the Ali store, and Dennis doesn't respond here or post what's going on at least.

This is beyond pathetic. I see Dennis has been online several times recently to read and ignore our comments about all the failed cells. So sad that he decided to tuck his tail between his legs and ignore the problem. This has happened at least a few other times with Vapecell, which is why I dont own any of their cells and likely never will.

Don’t forget to file your AliExpress disputes to get your money refunded. If that fails, file a charge-back through your credit card company. Also please leave appropriate negative feedback to warn others. For those who visit similar forums, spread the word so others can avoid this vendor and their disappointing non-existent customer service.

Its alright Dennis… I just did my part on your behalf to allow you to save face and continue hiding your shrunken head in the sand. Maybe you’ll be reincarcerated as a ostrich some day soon, so you can continue doing what comes naturally!

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…