Overcharged 18650 to 4.5V

Yelov · 2019-08-22T22:48:10.000Z

I think my Liitokala lii402 charger is broken.

Basically I had 2 samsung 30Q batteries at around 3.8v I think and put them on the charger. It showed that they were at only 1 out of 4 bars charged. I took them out right now and in multiple flashlights it’s showing 4.5 volts (4 blinks followed by 5).

What am I supposed to do now?

Do I just discharge them normally by using them in a flashlight or are they going to explode or something?

Henk4U2 · 2019-08-22T23:14:02.000Z

A battery is like a see-saw between energy and chemistry.
The internal chemistry changes every time you are charging and discharging a battery.
Over-charging and over-discharging may lead to an unwanted or irreversible chemical composition.
My best guess is that a 30Q, a strong work-horse like battery, can take some beating. But not too long.
I you suspect there is something wrong, try to establish normal working conditions (2.8V-4.2V) asap.

Question, did the battery get hot when you overcharged it? If not, put it in a flashlight and shine away!
If the chemistry of battery is irreversible changed or damaged you might notice that the capacity is lower.
Next time when you charge the battery, check the temperature (back of the hand/fingers).
BTW=> Never charge a battery un-attended!

Yelov · 2019-08-22T23:23:33.000Z

No, the batteries weren’t warm when I took them out. I tested the voltage across my 4 flashlights, it was mostly 4.5V or 4.4V on the other battery. Only my BLF Q8 showed 4.3V.
I’m probably going to try to discharge them, I just really hope it won’t blow my hand off.
Btw I was constantly looking at the charger, it was still showing that they weren’t charged. I took them out and tested the voltage because it was taking too long and that’s how I found out.

ChrisGarrett · 2019-08-22T23:31:26.000Z

Something’s wrong, as 4.50v is way out of spec…

I’d ditch the charger until I confirmed things with other known quality cells.

Chris

Macka17 · 2019-08-22T23:42:47.000Z

Use a Milti. Check them properly. ($10)

Price of Chargers. and price of battery’s.
In regards to value of your hands.
There’s plenty of coupons around for both.

I wouldn’t have asked.
They’d already be outside in bin.

Those things ARE mini Handgrenades if anything gets off balance inside.
Don’t take the chance mate.

Actually, a coupla chargers is good. for several reasons.
I have a XTAR VC4. for multi Batt Torches (4 cell) Get even charge right across them that way.
Then a VC2 for travelling, and covers individual battery’s from most of my torches.

Whoops. That VC2 does not charge my LI-Po4 10440’s Drrrr. Didn’t think to check.
LiitoKala Lii202. That does.
Hmmm. Now I got 3.??? Less than $20 for all 3.

Yelov · 2019-08-22T23:49:36.000Z

I put the two cells in my BLF Q8, went outside and let it run on turbo for 5 minutes on the ground. It’s showing 3.9V in BLF Q8 now or 4.1V in my other flashlights. I don’t know if they still have the potential to be dangerous if they are at a safe voltage.

And ye, I’m not gonna use the charger anymore. Actually I wrote a mistake, it was a Liitokala lii202, I’m now waiting for Liitokala lii402.

SIGShooter · 2019-08-23T02:02:48.000Z

Yelov:

I put the two cells in my BLF Q8, went outside and let it run on turbo for 5 minutes on the ground. It’s showing 3.9V in BLF Q8 now or 4.1V in my other flashlights. I don’t know if they still have the potential to be dangerous if they are at a safe voltage.

And ye, I’m not gonna use the charger anymore. Actually I wrote a mistake, it was a Liitokala lii202, I’m now waiting for Liitokala lii402.

You should definitely get a DMM since it’s questionable how accurate the voltage checks are in flashlights.

BlueSwordM · 2019-08-23T02:14:35.000Z

Get yourself a multimeter.

I really doubt it’s at 4,5V.

everydaysurvivalgear · 2019-08-23T08:03:08.000Z

Should be okay seeing as they are brand name cells. Back in the days on here these Russian swore by charging all there cells to 4.4v because it gave them a performance boost lol.

Cereal_killer · 2019-08-23T08:11:19.000Z

A lii202 is a well regarded safe, simple charger. Idk if there’s fakes you need to worry about but most importantly, as others have said, GET A DMM!! You’re probably fine but right now you have no way of knowing. Voltage display functions in a flashlight are for basic monitoring during use, not for measuring voltages of a cell with possible safety issues.

Even the worst quality dollar store junk DMM you can buy will be more repeatable and accurate then voltage check in a flashlight…

varbos · 2019-08-23T11:47:07.000Z

You need to throw the cell out the window immediately and then duck

Th558 · 2019-08-24T00:15:17.000Z

Just make sure it doesn’t explode when it hits the ground (place something soft on the floor). Also it’s best to have a fire extinguisher at hand just in case…and if you don’t think it’s worth the risk you can always throw it in a neighbours house. just make sure you’ve got a lawyer ready.

Boaz · 2019-08-24T00:27:44.000Z

Yep ..odds are really good it wasn't 4.5v

either way you need a DMM

Macka17 · 2019-08-24T08:38:54.000Z

Nothing goes into charger. out of charger.
Into any torch in this house without a reading first.

I Keep all spares in Pr’s with V’age written on casing in Texta.
Brand and V matching.
Those things are too volatile if things go even slightly wrong.

snakebite · 2019-08-24T20:20:51.000Z

for sure dont use that charger again till you find out if it is overcharging.
dont want to be priming incendiary grenades!

bushmaster · 2019-08-24T21:38:18.000Z

I’ve had several chargers over the years that overcharged batteries. I just junk them Even the ones that only charge to 4.25 I do not want because they shorten the life of your cells. Believe it or not, I meter every cell that comes off my devices. I don’t meter the cells that come off my charger normally because it is an analyzing charger and shows the basic measurements of the cell—may not be accurate but will alert me to anomalies in my battery stock. Then I can look further. JMO

Barkuti · 2019-08-25T13:17:49.000Z

Others have said this already but “flashlight blinks” is no proper meter. Likely inaccurate.

A multimeter is the way to go. There are plenty of inexpensive, low voltage precise units fine for hobby use. Check some at Henrik's site.

Your cells are tough and just were slightly overcharged. That's all. 0 issues.

WalkIntoTheLight · 2019-08-25T13:32:32.000Z

Yeah, as many others have said, get a $10 multimeter that will give you far better accuracy in voltage measurements than any flashlight will.

Lights like the BLF Q8 will give you a rough estimate of voltage, but mine blinks out a reading that is about 0.1v - 0.15v too low. YMMV.

If you really did charge those cells to 4.5v, I’d be very careful about using them. They might be okay, or they may have been damaged. It’s difficult to tell. At the very least, charge them to 4.2v and let them rest for a couple of weeks. If they drop below 4.15v over those weeks, they’re probably damaged. Running a capacity test on them is also a good idea, but it sounds like you don’t have the equipment for that.

You can safely charge to 4.3v, though it will cut down the number of cycles you will get by about half. Higher than 4.3v is unsafe, IMO. If you’re concerned about safety, it’s probably best to get rid of those cells.

Barkuti · 2019-08-25T14:57:36.000Z

WalkIntoTheLight:

… Higher than 4.3v is unsafe, IMO. …

In all honesty, cells/batteries are subjected to a lot more voltage stress (overcharge) in UN/DOT 38.3 transportation testing for lithium cells and batteries (there was a downloadable PDF document somewhere). And batteries don't blow up.

Even if those 30Qs were at ≈4.5V for a small while, this means they probably lost a few cycles and that is all. They are perfectly fine otherwise.

WalkIntoTheLight · 2019-08-25T19:37:02.000Z

Barkuti:

WalkIntoTheLight:

… Higher than 4.3v is unsafe, IMO. …

In all honesty, cells/batteries are subjected to a lot more voltage stress (overcharge) in UN/DOT 38.3 transportation testing for lithium cells and batteries (there was a downloadable PDF document somewhere). And batteries don’t blow up.

Even if those 30Qs were at ≈4.5V for a small while, this means they probably lost a few cycles and that is all. They are perfectly fine otherwise.

Yes, that’s likely true. But the user has to balance that with safety, and decide how much risk they’re willing to take. There’s always a risk with lithium-ion, even when used “normally”. It’s very small, but that risk does go up when operated outside the recommended specs.

These cells aren’t even supposed to be used for flashlights. Large currents, anode and cathode right next to each other on one end of the tube, with just a small plastic or cardboard separator, and a really thin plastic wrap, to stop an easy short. I can hear government bureaucrats wringing their hands…