Concerns over Sofirn's 18350....

The 18350 cell has a rapid charging current of 0.5C of 850mAh which = 425mA. This is a concern when they offer a short tube for models that charge as high as 2A. The IF19 I received to review charges this cell at 1A. I messaged my contact and they tried to convince me that despite the datasheet, it’s completely safe. I’m sorry Sofirn, but you can’t just ignore the specs. You don’t mess around with lithium cells and misuse them. The below image shows a min cut off voltage of 2.75v and some flashlight models don’t stop there either.

I’ve addressed this concern many times over the past two years and been ignored. I remember bringing this up on the Sofirn Facebook group and I was called a Karen (not by Sofirn) for voicing my concern. I’m surprised by how many have no idea about Lithium safety, or just straight up choose to ignore the dangers, even by those that should know better. If you know the dangers and ignore the specs, I have no issue with that, but when it’s been sold to people who don’t know, that’s where my problem lies.

Image below is found on their AliExpress listing
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It won’t immediately kill you. Make sure that it doesn’t get too hot. If it feels hot, it is too hot. But the high charging rate will drastically reduce the lifespan of the battery.

I never charge 18350 internally (except the charging controller is set to an appropriate current). Often the light is designed for 18650 and the current is too high. The IF19 is designed for 18350, so 1 A is too high. 500 mA would still be high, but acceptable.

You’re not a Karen, this is a major issue with the light and must be fixed by Sofirn.

As long as batteries are not getting more than just a tiny bit warm, I don’t think it’s a safety issue. Is it shortening their life cycles? Yes. Never charge unattended. I always use a USB tester to watch/check the amps.

As they age, resistance goes up and what may have started out okay, could be a didn’t story down the line. If it was on an external charger and sold to those who know lithium safety to monitor, it’s not a big problem, but charged inside the light and sold to just anyone with no lithium safety mentioned in the manual, is a rather big problem. I never push cells over safety limits in datasheets, manufacturer’s put them there for a reason.

Good info, thanks. The IF19 is on my radar, but one of my concerns is the OBC. Although I externally charge 90 percent of the time, it IS a stated feature and should function safely within cell parameters. Might not be a huge concern for cells like Keeppower 1200 mAh that specs max charge rate at 1.1A, but obviously not ideal as 220 mA is recommended standard charge rate. My other concern is charge termination. One of my two IF22A overcharged to 4.26 before I pulled the plug. I don’t have a USB tester, so not sure if it was still applying juice before I cut it off, but I don’t trust it now. Sofirn needs to step up and resolve issues like these.

The first batch of IF22A’s had a driver issue and many had charging failures. 1Lumen had theirs charge to 4.8v I think. I had to replace 4 units in my store due to the same problem.

Which light are you referring to? Have you known of any models that’ll try and charge a cell showing 1.2v?

The if19 is not a practical light that people are going to be charging and discharging 100 times over the course of the next year. The battery is never going to get anywhere near the 500 or so lifecycles it is rated for at those listed charging rates. Leaving it charged at 100% well shorten its life more than charging at one amp.

Despite what you think, you don’t misuse lithium cells, period.

Had a customer tell me about charging a lithium battery at night, he fell asleep and woke up to his dog biting him, trying to wake him up with smoke filling the room. Found his charger to be at fault.

I’ve also seen multiple incidents over the years of flashlights exploding due to cheap Chinese cells or from misuse of the cells.

I’ve had a Sofirn SP33 V3 make a battery vent from over current. Customer must have used something that shouldn’t have been in there at 2A and it vented.

I talked about the same problem in the comments to the review (cpfitaliaforum) of the Wurkkos TS21.
With my powerbank TS21 get up to 3A on the 18350 supplied by Wurkkos.
I decided to change the 18350 for a keeppower and then I prefer to recharge via my charger and not via the USB port.
3A or more than 0,5A on those 18350s are not good.

I understand your concern. “Most” of the information on the data sheets is not about safety. It’s about capacity and life cycles. All of the masses should be using lights with protected cells.

I bet that any number of people use 16340’s in 18350 lights so that would be an even bigger problem given their smaller capacity. From looking at a review on the Sofirn SC21 it charges at 0.95A which is much higher than 1C for a 16340.