Olight UC charger almost burned a hole in my finger...

Batteries and Chargers Chargers
1

I’ve been really unlucky with 26800 cells. First my convoy L8 shorted at the mcpcb due to the lack of screws securing it and the positive wire got pinched with the twisting of the reflector and now this…

First time using a new Olight UC charger to charge some 26800 cells, first couple hours was working fine and then noticed a strange behaviour it started flashing red and the body was warmer than usual. Tested via a USB power meter and confirmed that it was shorted. Right after recording the video I unplugged it but was still holding the charger with the battery attached and suddenly it got EXTREMELY HOT in that melted spot and burned my finger. It wasn’t power from the USB adapter, the UC charger was drawing power from the battery…

Video is uploaded as a short and I can’t link it here, click to view the video:

You can see some of the blue plastic fused into my skin:

2

Make sure you report this to Olight. This is the second time I’ve seen a similar issue with this charger. (Might need to remove it from my charger buying guide).

3

Wow, thats BAD. Im glad it was not worse.

I use one of those chargers, it has been running for the last 5 years without issue, but

I have never tried to charge such a large battery, and I have never unplugged the USB with the magnetic contacts connected to a battery.

I applaud you being present and vigilant during the charging process. I also monitor the charger, I use it at my desk, never unattended. I also touch the battery periodically, to confirm there is no heat buildup. And I use a charge monitor, so I can confirm the charge rate tapers down to Zero and shuts off.

I have never tried to touch the charger USB plug to monitor for heat… that is a good additional safety check.

I will be very interested to know what caused the failure, if you manage to figure it out. From what youve shared so far, it seems the charger developed a short, and the red charge light started flashing, which is not a normal behavior.

The last part you shared, about leaving the battery connected to the charger, but unplugging the charger leading to power drain through the short, is an important factor to be aware of… I have never connected the charger to a battery, when the charger is not plugged in, and will certainly keep that in mind as something not to do.

Thanks for sharing your safety report.

any info on what caused it, or what battery size was involved?

4

Well that’s no good at all. Glad you were there to notice and intervene. Those 26800 take like 10-14 hours to fully charge on that little thing…easy to go about life and not be present for that long.

I’ve had one for several years now and it’s been fine. Actually charging 26800 is the only time I’ve noticed that it got pretty warm, but that was hours into the cycle and it never got what I’d call hot. Normally it runs pretty cool even when it’s delivering near it’s max charge current. I’ve never seen a teardown on these but the circuitry must be a little more sophisticated given the smarts it has. Makes me wonder if a simple diode failed or a chip that’s controlling direction in more than one way…and since it’s new, if it’s perhaps a victim of the chip supply problems or just poor assembly/qc.

I’d send it to Olight and given their other mishaps for awhile now and responses to same, I’d go ahead and send it to the CPSC as well, get it on record. I don’t know that this charger is necessarily one of them (and mine has been perfect), but I am so tired of poorly designed and failing electrical products being sold in this country without much oversight or prevention. Defects happen but in general the electronics (especially a lot of things designed for a/c power) are quite poor quality these days, skirting the edge of safety and reliability.

5

I had one that stopped working 2 years after I bought it. I contacted Olight and they said that the warranty period for it was up (nowhere is that mentioned on their website) and I could just go out and by another one.

It’s not as if it’s that expensive an item; I just wished that they would state their warranty period for it on their site.

I had used the charger less than 10 times so hardly overused in my opinion :partying_face:

6

Will34, curious what brand and specs those battery’s were. They just have a generic orangish wrapper with no markings. (not saying that the Olight is not at fault).

7

Maybe that’s the reason they sent me two when I ordered (and paid) one.

I guess this is related to the bridge that changes the polarity of the output. Maybe a conflicting control input or something damaged, but in the end both terminals got shorted together which will kill the charger in a matter of milliseconds.

8

Looks like a Queen Battery 26800 cell. People are using chargers like this (I’m using the similar Nitecore LC10) because few chargers are able to fit 80mm cells without modification.

9

Wonder if the Olight design predates the 26800 form factor? I see that they claim it does all sizes, but they have a chart and the chart ends with 26650. Could be a product malfunction, but I’d let the factory know for sure in case the amount of power needed to recharge that large of a cell is overheating/overstressing some component and is what caused this. Might be the first of others to follow. Thank you for sharing, I have (and like) a couple of these and have earlier given them out as gifts to muggles.

Compatible Battery Model List Below:

10

The size won’t matter. It always charges with the same current and to the same voltage. There’s really not relevant difference except the capacity and that’s not a factor because charging just takes longer (where the temperature of the charger has already stabilized). Also it wouldn’t be different from charging two smaller batteries one after the other.

11

The cell in the video is a QB26800, however the compatibility chart is just for reference. The charger is designed to work with lithium ion and NiMh chemistries, it draws exactly 0.689mAh at 5V to deliver 750mAh up to 4.2V. sure, it could’ve taken longer and warming up more to charge a 26800 than a 18650 cell but the same would happen if you charge several cells nonstop, and there is no mention anywhere that the charger has a duty cycle.

The only “unconventional” thing that I did was unplugging the charger while the magnets were still attached to the cell, but the same would occur if the lights go out or the powerbanks depletes.

The polarity detection system takes about 3 second to work and I suspect it is FET controlled, it’s the only component capable of producing this amount of heat in such short period of time. The USB adapter is only able to supply 5W, so it had to be drawing power from the battery. That was a soldering iron type burn which requires a good amount of amps.

I ended up using just the magnets because the cells still needed to be charged. will update when Olight responds

12

The other incident was reported on Reddit r/flashlight. Not sure of what battery, but the same component melted.

13

The other incident was reported on Reddit r/flashlight. Not sure of what battery, but the same component melted.

14

Ouch! Sorry about your finger. Thanks for the graphic reminder to never trust a device while recharging its cell(s). This can happen to any charger/BSM/catastrophic cell failure conundrum. Its far more common in lithium powered devices than are reported (including high end, name brand, consumer electronics). I usually recharge my cells & devices in my bedroom late in the evening so I am present if the worse happens. Always unplug if leaving unattended and resume upon return. I own several Olight UC chargers and haven’t had a problem with them… yet. But that means very little.

15

The size shouldn’t matter with one caveat, this charger apparently has an 8 hour timed shutoff, so you would have to charge until shutoff and then charge again, though I would imagine that would be true for 26650s as well.

As far as this thing drawing power from the battery, perhaps the similar Nitecore charger is safer since it’s designed to do that and work as a power bank when attached to a charged battery.

16

Royce, where do you see something about a timed shutoff? Mine definitely does not do that…several times doing the 26800 for 10+ hours (which is ridiculous and why I mostly charge them inside of lights). I don’t recall seeing that on the package card, just snooped around a little and can’t see that mentioned anywhere. Is that something new for this charger?

17

When I was looking into a 26800 charging solution I came across the info. I believe it was a response from Olight to a question on the product page.

18

Hmm. I was looking on their pages (us and global) and went through about ten pages of reviews going back a few years and didn’t see that. What I did see is that they are quite poor with responses, like it seems they don’t understand the questions sometimes or lack the basic tech knowledge to answer well, maybe a language/translation thing though. I always use mine with a pc usb port or 2.4A wall wart, though, but I don’t think that should make any difference really. Certainly has never shut off prematurely yet.

19

Their answers also seem to contradict one another at times. Here’s the one I was referring to:

From this page https://olightworld.com/olight-uc-magnetic-usb-charger