Ok, just got my 1st smart charger, the Vapcell S4+ 2.0….
I have (4) dead Sofirn 18650 batts that read 0.02V. Do I attempt “repair” or just throw them away? If an attempt is made, do I need to keep watch on anything or just hit the “Repair” mode and let it do it’s thing?
Are “repaired” batteries as good as normal….or weak, or dangerous?
Thanks for any thoughts!
Basically this, even though it talks about protected batteries and overcoming issues with that: BU-808a: How to Awaken a Sleeping Li-ion - Battery University
Or in short - there are certain risks involved, certain processes can happen in overdischarged battery which can make it unsafe. You have to monitor the batteries closely and if any anomalies happen - discard. Definitely not something to leave unattended.
Also “restored” batteries will likely have lower capacity and can be unsafe.
It is your call, but unless this are some special batteries which are hard to come by or expensive (which definitely is not the case for 18650) my opinion on fully discharged li-ion cells is generally - discard.
Ok, read that article….these batteries have probably been at 0.02V for months. Doesn’t seem safe for a novice to mess with…will just get new ones when needed.
Guess I was just hoping to put the new charger through it’s paces.
Thanks for the heads up :+1:
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Throw that Crap Away —— Nothing below 2.5v is my rule —- You could maybe give them a shot if you went below that by mistake and immediately charged them back up — But never below 2v in any instance
These batteries are from an LT1 lantern that crapped out after only a handful of uses in 2 years. The lantern would then not even work with another set of good, working batteries. I gave it away to someone who wanted to tinker.
What’s more likely, the suspect LT1 killed the batteries….or the faulty batteries killed the LT1?
Barry @Sofirn offered no solution.
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Is there even a way in which batteries can kill something without that device being faulty itself and excluding incorrect batteries, reversed polarity or leak?
I can not think of any…
Likely batteries got overdischarged either by faulty lantern or normal parasitic drain. To avoid that take the batteries out or unscrew the cap to break connection when you are storing things for a long time…
But, still wondering why the LT1 went belly up just sitting there in a closet? I thought another set of batteries would bring it to life, but nope.
Yeah, I think I’m getting more interested in the hobby again….need to pay more attention to lithium concerns :+1:
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Yeah, I’d recycle those and not even bother with trying to revive them. 1) Although the Sofirn/Lishen cells are pretty decent in performance, they’re still not as good as the major OEM brands and that might increase the inherent risks of reviving cells that low. 2) If they had been that low for only a couple days or so, it might be worth it to slowly revive and monitor them, see how they do, but after months in a state of full discharge, dendrites and shorts are pretty much a given, so it’s just not worth the risk at all, even if they charged up ok the first time. I’ve brought back lots of good quality Sanyo/Sony/Samsung cells that were between 1 and 2 volts and had been sitting in their packs that way for a long time, but they did lose specs and were relegated to low drain things only…all but a few are still doing fine, though, just lower capacity and a bit more voltage drop after charging but it settles and maintains. I wouldn’t do it with zero-volt cells or any of the chinese cells (except possibly Molicell but not sure if anyone has tested any of their cells in this way yet).
For me, I don’t care what light it is - it gets a mechanical lockout if possible. If not, the battery comes out until needed unless it’s a regularly used grabber. Things like parasitic drain, polarity protection, and low voltage cutoff have been moving targets with our light manufacturers. Seems rare now that they get all three right and well designed. The trend toward aux lights compounded the drain problem and many newer enthusiasts never even think about something like that.
Since you have the new toy, and you have some drained cells, then in the interest of learning something i say give the “repair” mode a try (assuming the manual instructs that this is a valid repair voltage condition).
If the drain was very slow over a long period of time then they may have some hope, especially if the voltage was not 0.00. If they were at 0.2 then this indicates a slight amount of ‘bounce-back’ from the bottom, which is used as a condition of a viable cell. Lack of bounce-back is an immediate fail. The “repair” current must be done at a very low rate, maybe the manual gives some info. i do this with a current limited power supply and bring the voltage up in steps. i have never had a need to use any repaired cells but have done the procedure just to learn about them.
that being said, there is always a big risk when messing with cells,
Is this Before or After he burns his house down
As cheap as batteries are these days I wouldn’t take the risk of trying to revive them. There would always be doubts in my mind that the batteries were going to come back and bite me. Actually I wouldn’t take the risk even if batteries were triple the going price.
4 batteries are worth what? The price of a hamburger and fries?
I know that everyone has different risk tolerances but I find that mine has changed, and is still changing, as I’ve gotten older 
Right to the recycle bin. Even if you did manage to force them up to 4V without incident they’re going to have like 5% of their original capacity and just die instantly again. Them cells is toast.
I don’t think sofirn uses LiShen for their 18650s. Just some 21700s. But I’ve been wrong before.
Exactly… IF, in the name of science; you do try the “Repair Mode”…. do it outside. 
And be sure to report back the results please. It would be interesting to know if it is a true “Repair Mode”.
Oh, good point…I get stuck on 21700 these days 
I think we had a couple threads on their 18650, seems like BAK was it. If HKJ did a thread/test it might be mentioned there, too. But my point - moderately experienced opinion - would remain the same for this situation and those cells.
I would have agreed with you if not for the 3 cells that came in the sp36 pro I just got this week.
They’re all over the place. Before putting them in parallel in the light I test voltage, they were all within an acceptable range of each other. Then I tried to do a capacity test using 1000mah charge and a 500mah discharge there’s no consistency. They all arrived at ~3.9V but the the longest one took over an hour longer than the quickest to finish charging. I ended the capacity test early because even with a fan pointed at them they were pushing 45°C at just 500mah discharge, and by that point it was clear the capacities were all way off each other anyways. I know 45°C doesn’t sound too hot but ive got a fan blowing right over the whole rig, it’s only 500mah discharge, and that was already 10° higher than any other cells ever reached in my little air cooled setup. Even at 1000mah discharge nothings else has got past 35°C.
I don’t believe they’re all 3 of the same model cell. Or there’s at least 1 odd one out.
They look the same and they’re wrapped the same. I havent checked under the wrap, but I should. The weights for the 3 are 44.1g, 45.5g, and 46.1g. I’m sorry that’s way too off. Cells sold in a flashlight where they’re going to be put in parallel should be nearly identical. Capacity should be within like 50mah not off by nearly 1000. And 2g between the smallest and largest cell is way outside standard variation IMO.
If let the cells balance out then use the light, or then charge it with the onboard charger, then take the cells out, and test them immediately after or let them sit for an hour outside the light they’ll be off as much as +/-100mV from each and the flashlight will warm up over +5-8°F if I put them back in, screw the cap back on and let them balance themselves back out again.
That post with the guy who had a cell vent in his Q8 (I think) doesnt sound like a freak accident to me anymore.
You can attempt reviving cells, as long as you do it where it’s safe.
I assume the ‘repair mode’ doesn’t use high currents and gives up if there’s no recharging going on and / or internal short circuit is detected.
Cells that have slowly discharged to 1 Volt or so (like from a battery pack with a protection and / or constant balancing circuit), but still hold that Voltage ought to be okay to revive.
It’s cells that have 0 Volts and have developed an internal short circuit (Copper dendrites i.i.r.c.) that only fools like myself would try to revive, by pulsing bursts of high charging current to melt the short circuits and then charge them normally.
It’s how i resurrected a hardly used Aspire 18350 after it was drained to 0.0 Volts in an e-switch light.
It didn’t take any charge anymore either, it measured 0 Ohms resistance on a multimeter.
The pulsing with high current i did outside, of course.
The cell did heat up a bit because of it.
But it was like 2.5 Volts at that point and it kept that Voltage like it ought to.
The cell is still in use today and didn’t lose any capacity or gain internal resistance.
In fact (for what it’s worth) according to the Liitokala NOR test it even gained a bit of capacity !
I.m.h.o. people often underestimate the abuse high quality cells are able to endure without the risk of venting, fire or explosion.
I have no experience with overcharging Li-Ion cells though, and i plan to keep it that way.
But as far as i know the problems and accidents that do occur rarely involve high quality cells charged by high quality dedicated charging circuits, except for E-vehicles., apparently.
I really wonder what causes those problems.
You’d think all necessary fail safes are built into those systems.
Well, any failsafe can fail…
Apart from that there are 2 things:
- Device manufacturers push the cells to the limit in order to claim higher capacity and in general better characteristics. They commonly use absolute maximum values instead of safe ones. Like charging cells to 4.25v (or even 4.3v in some cases) instead of 4.2 is common, along with slightly higher than normal cutoff temperatures etc. They also regularly allow recharging overdischarged batteries, since “dead” device means RMA which they want to avoid as much is possible.
- Users are very creative in finding ways to overcome failsafes. How many phone (or e-car, e-bike etc) users understand (or want to understand) that battery is high density energy storage and has to be treated with, at least, a little bit of respect? Very few. The batteries are commonly charged at unsuitable temperatures, be it hot or cold/below zero. They are commonly overdischarged, subjected to physical stress etc. And then used despite obvious signs of failure like increased internal resistance, decreased capacity or even swelling right until it completely fails.
Combining this two no wonder that accidents happen. Accidents are not really more common for e-vehicles than other devices, they are simply more “visible”. Car burning on a road makes the news more commonly than a phone bursting into flames with no serious consequences like house fire.
I think this mostly true but
I think companies are actually getting a smarter with how they design batteries and chargers after watching how consumers treat them. They recognize cycle life is important and they also realize yes the average consumer has no idea how to maximize cycle life on their own, but when the consumer ruins the battery they return it and blame the manufacturer, so how can we fix this? I think it’s harder to ruin a battery now than ever.
Tool battery chargers for example never charge to 4.2V anymore. Usually they fast charge to 4V and stop, because they know people just leave the things on the charger for months at a time. A lot of them won’t even let you charge it if it’s near 4V. Milwaukee’s M12 chargers just refuse to charge a battery until it’s below 75% SOC. All of them have temperature management.
Phone batteries on the other hand do push the limits. Mine charges to 4.4V. But these are LiHV pouches. Not the same. The things aren’t cheap. And they put a battery saver mode on the thing that lets you cap charge at 85% if you want to and have all kinds of battery saving temperature monitoring adaptive charging features.
EV batteries are water cooled of water heated if necessary. You can even tell the car you’re about to start charging it and it’ll start getting the battery to optimal temperature. And ya, the fast chargers are really powerful, but they’re still only 2-3C, and nobody has a fast charger at home. Most people have level 2 EV chargers that use closer to a 0.1 charge.
As for charging to 4.25V. Spec sheets almost always state end voltage to be “4.20V +/- 0.05V”. But also, ill put this out there. from a Samsung 25s datasheet:
9.1 Overcharge test
Test method: Cell is to be discharged at a constant current of 0.5A to 2.5V. The cell is
then to be charged with a 20 V and 12A. Charging duration is to be 7 h.
Criteria: No fire, and no explosion.
9.4 Heating test
Test method: To heat up the standard charged cell at heating rate 5℃ per minute up to
130℃(266°F) and keep the cell in oven for 1 hour.
Criteria: No fire, and no explosion.
The cells you’re buying had examples they were literally putting an over for an hour and didn’t explode. That’s a robust cell
Well, yeah, not great, but we rarely rarely ever see the same kind of consistency with chinese-branded cells as we do with the major OEMs. Basically every aspect can be subject to variation but with the better ones they can be more than acceptable and once in a blue moon they match so well as to rival the majors’ cells. I’m a little fuzzy now but it sounds like you’re doing a good job trying to approximate the methods used by the majors for discharge tests…that can be hard to duplicate on a normal consumer charger but it’s usually close enough. I think the standard (Samsung, anyway, which is what has always stuck in my head) is a 0.5C charge with the standard trickle end period, followed by a rest for an hour or so, then discharging at 0.25C allll the way down to like 2.7v. That should come pretty close, but slightly higher temps around that 40C area can reduce by like 3–5, of course higher discharge currents and their resulting extra heat can reduce it further. That end discharge voltage does vary by brand and some kinda “cheat” by calling out a 2.5v spec…which is fine for high quality cells but I think a poorer choice with what we’ve seen overall with chinese cell brands. Also some cells that have been on the shelf for awhile may take a few cycles (with rest time) to come into their own, so they may level out and become closer to each other with time (but maybe not). I like to do a simple cycle with new cells and then let them sit for a week or so and repeat, then just check a couple times over the next week or two and for the first in-use cycles, just to know where they stand.
All that said, I haven’t gotten a Sofirn 18650 in a couple years, and the covid complications in the supply chain really were a challenge for everybody for awhile (the manufacturing delays but also a super ramp up in demand with e-bikes and scooters that are/were still using 18650)…so manufacturers and retailers were both scrambling for supply, and who knows what Sofirn needed to do. We do know that they have used at least four different (five?) cell manufacturers over the years for various sizes. That and typical variation…leaves the door open to just buying known good cells that are well-matched from the major labels for lights like this. In single cell lights, so far Sofirn’s cells (except maybe the 14500s) seem to stay very good to excellent. Can sure do worse, anyway, and the represent a very good value when bought/included with lights (notsomuch when ordered separately but that’s typical now compared to just a few years ago).
We do seem to see more frequent problems with these multi-cell carrier platform lights, from many brands. I think it may have to do with….relaxed standards….that are more typical than not with many chinese manufacturers and engineers in our niche….same bleeds over into QC and such, and there’s a very real cultural perspective involved in all of that and is a constant battle for companies manufacturing over there in all types of products. Sometimes it degrades to the whole chabuduo fiasco, sometimes it’s just an irritating variation in quality. I think “they” all need to take lithium-ion devices a lot more seriously at all levels…right now the trend seems to be simply moving to protected cells rather than a better engineering and component sourcing approach.
That’s not the case with cells Ive taken out of new power tool battery packs. Since the pandemic everybodys using china-brand cells in some of their packs. And it’s not always BAK, Eve or LiShen, you should be so lucky. Real china-brand stuff. Cells from obsure 2 year old companies you’ve never heard of in $120 battery packs on the shelf in home depot.
They aren’t good cells, but they’re always nearly perfectly matched. Internal resistance matched down to the within 2mohm, capacity within 10mah. So they’re able to do it. I’m guessing the quality control is just higher with the stuff they deliver to these tool companies. I’m sure there’s a computer matching these cells up. They probably have $20mil+ contracts with strict QA requirements.
With these multi-cell lights from a small flashlight company I doubt they’re buying pre-matched cells in groups of 3 or 4. They’re probably just buying them loose by the crate and taking a random handful out of the box and throwing it in a light.
Things have definitely changed since before the pandemic. I mean just the prices for the raw materials have gone up a few hundred percent. It’s not like the issue is just stuff that uses 18650s, it’s anything that uses a lithium battery. Especially EVs, since they use like 9000 of the things. They’re all competing for the same raw materials.
EVs are really screwing us. <100,000 metric tons of lithium metal gets mined globally each year. An EV uses somewhere between 15-200lbs of lithium per battery, nobody really knows. None of it gets recycled, not back into a car anyways. Let’s be really conservative and pretend each one uses 20lbs. 75 million new cars sold a year worldwide before the pandemic, expected to hit those numbers again next year. If 15% of those are EVs that’s the entire world’s lithium production right there. And they want 50% by 2030. Outlook does not look great.