Beware Vapcell (Poor QC)

Hi Mooch

If the voltage is too low, there may be a slightly larger self discharge phenomenon. The voltage at the time of shipment is OK, but after a long time of storage, the voltage of some batteries will slowly drop, such as 0.005v or lower every day.

At present, the technology of K30 has been solved to make the voltage more stable

Self discharge problems still exist in some brand batteries, but the proportion is much less than before, and lithium battery technology is improving

The K30 voltage in the video is lower than the cut-off voltage of the li-ion battery, which may have a little impact on the performance, but it is still safe. The built-in protection device is still in place. In case of short circuit or huge current output, the protection will be started, and the battery will fail. The explosion-proof valve device has nothing to do with the voltage, but with the internal pressure of the battery

Low voltage battery can be repaired by charger. The voltage is restored to the normal voltage and then used in some equipment
If the conditions are not met, it is not recommended to use

Low voltage will affect the performance of the battery, such as 3000mAh battery, the capacity of the repaired battery is only 2950mah

Pay attention to daily use, do not let the battery voltage too low,do not lower than the cut-off voltage

At the same time, the use of batteries will also cause performance loss. Li-ion batteries all have service cycle life

If the battery has quality problems, please contact the after-sales department

Thanks

The CID internal protection device can only open up and release the pressure AFTER a cell has started to go into thermal runaway, doing nothing to prevent runaway from occurring. Yes, it can activate and shut down the cell if there is just some excess gas generation but that is it. I’m confused why you mentioned the CID though. You’re saying it somehow makes the cell “safe”? If that was true then no Li-Ion round cell from would have ever caught fire and/or burst.

When over-discharged for a long enough time some cells can suffer from dissolution of the negative (copper) current collector. This copper then replates itself back onto different parts of the cell when recharged. This can never be called “safe”.

Since we do not know if the K30 can experience this, and we cannot know the internal condition of the K30 cells here that were overdischarged, we cannot say these cells will be “safe” when recharged.

This does not mean they are dangerous. We just don’t know what might or might not be going on and that means we can’t toss around words like “safe” just because we want things to be that way.

I am glad that the quality of the K30 cell has been improved but I am disappointed that Vapcell has decided to leave the lower quality cells on the market and not alert your customers about this problem and issue a recall.

So this is just a defective lithium ion cell, it can happen to any manufacturer.
The solution is to check the batteries with a voltmeter before charging them, or use any kind of modern charger that would detect that the battery is overdischarged and faulty and then not charge it.

The risk of venting happens when the battery is recharged after being overdischarged, which could happen if it was in a battery pack, or a dumb charger.
But anyone building battery packs knows to test and balance all cells before joining them, so this would not happen.
And all good quality modern chargers have detection for damaged cells that have a voltage that’s too low.

By itself, the battery would not vent or explode.
It would need to reach –12% charge in order to form the dendrites that would cause an internal short.
https://www.nature.com/articles/srep30248

120pcs were at 3.69 - 72v which shows the other 39pcs have higher than normal self discharge. I’m not selling them on to my customers knowing this. I’ve always tossed cells with higher than normal discharge. I’m certainly not taking that risk when I’ve seen torches exploded from unstable cells.

The 30Q is shipped at approx 30% charge, I’ve sold roughly 1000pcs+ and all measured at 3.44v.

Lol yeah that'll rain on your parade for sure! Kinda reminds me of how one can tell when a cantaloupe is rip.

"A perfectly ripe cantaloupe emanates a fragrant, sweet, vaguely musky scent that's easily detectable through its thick rind. If you don't smell anything, or the aroma is really faint, the fruit isn't ready yet; if it has an unpleasant odor, it's already headed downhill toward rotten."

Is this really the case? I have laptop pulls that went into storage +3 years ago at ~3.7v’s and when I checked them last week they were still at ~3.7v’s. A .005v drop per day is 1.8v’s per year and I certainly would have noticed that in those batteries and even in the ones I use normally, some of which have sat unused for a year or more.

Sorry, K30 didn’t receive customer complaint about battery voltage before it was sold

About a year later, we saw BLF, the low voltage problem of K30

We speculate that K30 should be the low voltage caused by the self discharge factor. The damage of this very small current to the battery is far less than that of the large current over discharge, and only once, without repetition

For after-sales problems, please contact the after-sales service

We will also monitor more batteries to ensure that good batteries flow into the hands of customers

thank you

Purchased from the 18650BS with the plastic wrap intact. They would have all been from the same batch since they’re always selling out, new shipments don’t last too long since it’s such a popular store.

18650BS refunded me and noted that they too had noticed bad QC and were strongly considering to discontinue stocking Vapcell.

That paper covers testing of large-format NCM-chemistry pouch cells. In my opinion we can’t extrapolate those (encouraging) results out to all round cells of any Li-Ion chemistry.

And if we can’t say that every overdischarged K30 cell will always be safe then we have to say that one or more might not be “safe” as a result of overdischarging.

In my opinion Texas Instruments wouldn’t have Copper Deposition Permanent Fail settings for some of their battery management system (BMS) chips, bq76952 for example, if this wasn’t a concern for some cells. Since the BMS keep any cells from dropping to a negative voltage that sure seems to indicate that the concern exists for voltages above zero volts.

I’m not saying overdischarged cells are “dangerous”. Just that we can’t use the word “safe”. The chance of an overdischarged cell going into runaway, in my opinion, are verrrrry low. But it has happened.

I have bought a pair of Molicel P26A from a European store about two years ago. Never used them and unfortunately I forgot to check their voltages by the time they arrived. However, lately I have measured their voltages. They were at 3.33V and 3.18V. I then charged them up to storage voltage (3.66V) and they still keep this voltage after a few days of observation. I guess I can consider them safe to use.

I’ll charge them all and let them sit for 2+ weeks, anything that’s discharging unusually high will be discharged

Does Vapcell use all the same cells from the same source for these or do they get them from different sources?

According to mooch’s testing, capacity is less than 2500mAh under 15A, much worse than 30Q

These cells have 5 legs and look like they are Chinese BAK Cell N18650CNP 2500mAh (15A CDR 30A Max)

It might be IMREN 30QP 3000mAh as well (also 5 legs but performs better that K30). I guess IMREN 30QP is a Chinese clone of 30Q - very similar name and the same pink wrap, LOL

The 20pcs I received a refund for were down to 4.08-4.10v after 2 weeks. Charged them up again and they lost over 300mAh. The other 19pcs were still discharging, but okay to bundle with flashlights and dropped to 4.15v. Charged a good cell and it remained at 4.19v

btw, you need to quote me for it to notify me of an update, only saw this as I was browsing the homepage threads

I am, but after awhile you no longer are notified until someone quotes you or you visit the thread again

I don't think quoting someone causes you to be notified.

You should be notified if anyone posts in a thread that you are subbed to, but that mechanic doesn't always work apparently.

What happened to the video?

I have four of their white 16340s and they’ve been as good as one can expect from ChiCom offerings, I guess?

Their other stuff isn’t grabbing my attention.

Chris

I’ve been going through spare cells I have in cases —- I had 4 of the Purple 18350s —I would guess around 2yrs old —3 were at 4.07 v and 1 was at 1 v — that was a total shocker