Well that’s a bummer to hear…they’ve seemed to be supplying such decent cells. Can you guys tell us when you received the cells and where you bought them? Maybe it’s a batch or something and not a more widespread issue. Do you have any older-ish Sofirn cells to visually compare with (i.e. have they perhaps changed cells for some reason)?
All my Sofirn 10 18650’s have been fine and don’t show any more voltage drop than any other 18650, which is to say nothing that is noticeable.
I have 2 of their 21700 batteries, both of which are identical in appearance. My bad one came with a light I bought earlier this year while the other one came with a light bought last year, both from their Amazon store. Maybe it’s just an issue with the 21700’s and not the 18650’s? Who knows, but Serlite’s battery was also a 21700.
It was clear to me that the bad battery was behaving oddly. Off the charger it dropped more than it should have after a day, and then keep dropping daily even when it should have stabilized afterwards. I made a note to check the voltage every week or so but then of course forget to do so :person_facepalming:
The problem with re-wrapped batteries is that we don’t know what we’re getting from one order to the next. Plus we don’t know how much, if any, quality control Sofirn or any other manufacturer is spending on their re-wrapped batteries.
Mine was about a year ago. It was a 21700 from a Wurkkos ts30. I assume its the same as sofirn battery.
I won’t / can’t comment on whether batteries are faulty or not. I assume folk here know not to store Li Ion batteries at either extreme (0 or 100)? For example my lights get used randomly - sometimes not for weeks - so I charge to 80.
My 2 Sofirn 21700’s were charged for storage, about 3.7v, so definitely not charged at full or completely drained states.
Sofirn’s cells are fairly decent from BAK and/or Lishen. I run my own flashlight business in New Zealand stocking large quantities of BAK and Lishen cells and haven’t yet had an issue. I check voltages of every cell before shipping out to customers and also run a discharge test on each batch to confirm authenticity on my CBA.
All cells from the main brands also have cells that go bad randomly, so it’s not something we can suggest the Sofirn cells could be problematic based on a couple reports. I’ve personally had bad LG, Samsung and Panasonic with high discharge from new, but that’s not to say those brands aren’t any good now.
Just tell him you’re testing out some eerie tannerite. :laughing:
I planned to use tannerite in my YouTube reviews for the hunting flashlights, until finding out it’s illegal over here. I have the supplies, but can’t mix them.
Thanks, Sig. I try to check each new cell as well but this reminds me there are a couple I haven’t yet. I think I have maybe 7 or 8 Sofirn 21700 in both 4000 and 5000, couple of which were received in the last six months or so. Just two of their 18650, and a couple of each in the Wurkkos flavors as well. Save for the couple I need to put an eye on they’ve all been stable and seem to be great cells comparable with the 50E that I prefer (I can’t recall now if the 4000 Lishen is on par with the 40T from HJK’s test but seems like it was close). Visually they all look the same to me other than the bottom ring/vent on newer ones…haven’t unwrapped any of them but I too have been assuming the Wurkkos were the same cells. Mine are a mix of Ali and Amazon going back about four or five years, but the majority of the cells came from Amazon since I usually buy lights without cells when shopping Ali (and my Amazon cells/lights are mostly from the last two years I think).
Hopefully a one-off problem cell/batch or something. Three people in this thread now, however.
Yeah hopefully it’s a rare issue but if someone is actively using a cell like that in a light how would they even know? The voltage drop is low enough that they would just think it’s due to using the light, at least that would have been my thought.
It’s only when the battery is stored and then checked before usage would it become clear that something is wrong.
The fact that the battery isn’t overly discharge in this scenario doesn’t mean that there’s no defect in it. How serious that is, if it’s even serious, is all speculation I would think.
Just part of the li-ion world. I do worry about that sometimes as we see more and more of them being sold on Amazon and such, and I have yet to receive a single light where anything appreciable is said in owner’s manuals about what we know as basic lithium safety/responsibility. The more e-bike and scooter fires we see, and the push from Samsung to label cells as “do not use, period” and restrict aftermarket access, the more important this basic education is becoming, imho. I guess it’s learn or be dumbed down by using only protected cells that have full protection circuits in them, which seems to be the way things are going with many brands. Nobody really takes it seriously anymore unless they short out a cell and catch a whiff, or if they actually witness a venting or something, and with all the new interest via this forum and youtube and reddit, it doesn’t seem that many take the time to teach new folks about it, either.
Yeah, I see this all the time in NZ, so many customers of mine already have existing lithium flashlights yet are shaken by learning that they can explode if misused. I include a printout on battery safety with each flashlight and also have a page on battery safety I’ve copied and slightly tweaked from BLF.
I remember one guy complained about his Convoy C8 blinking at 2.8v, I learnt he ran all cells virtually to 0v each time in his vape and was annoyed he couldn’t do the same on his light.
One thing I never see mentioned is battery safety when mounting a flashlight on a rifle, button top must be used otherwise one risks the spring denting in the top and blocking the relief vent. I’ve had people questioning why I state “button top only when mounting” and after I explain a cell could potentially explode if that vent can’t open, I never hear from them again, probably went back to AA’s.
I’m never amazed by people who do dumb things and/or don’t bothered to read up on things that are potentially dangerous. It’s just the world we live in now where people assume everything will be safe and that they’ll be taken of because of…….reasons.
Lotta people have the cellphone mentality. Ie, run it down ’til it shuts off on its own, plug it in to recharge, rinse, repeat.
People who get “protected” cells assume the same. After all, it says “protected” right on the tin!
But doesn’t Sofirn add protection circuitry to these 21700 BAK/Lishen cells?
Is it this protection circuitry that might be to blame for high self-discharge?
I have a Sofirn 5000 mAh 21700 cell.
It is unprotected.
When HKJ tested it, he noted that he tripped a protection fuse in it. Based on that, I assumed it was protected, but maybe I misunderstood something?
Mine looks a little different than the one that HKJ tested, but the one that HKJ tested is 71.0mm long, and at that length I think protection would be impossible.
Protected cells are typically at least 4mm longer than unprotected cells, so I’m not sure what HKJ is talking about.
I’m guessing it’s just basic overload/overcurrent protection that’s built into the base cell, but it doesn’t have the proper “Protected” circuitry that also triggers during over/under voltage conditions. So maybe Sofirn did not add anything to it afterall?
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