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FYI Warning Charger Fail

Antharak

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I bought a pointer off ebay from a no name company, it came with a 18650 battery and charger. Tried the pointer out and then put the 18650 protected battery in the charger. At this point the battery read 3.1v, checked before it went into the charger.
A few minutes later I get that " I'm burning up" electronics smell :wtf:. Well the battery was too hot to touch and the charger was just a tad cooler. I let it all cool down, not knowing if the battery was about to explode or not, My first time with a 18650 Li-ion or any Li-ion, rechargeable.
Well the battery read 0.00v, oh well R.I.P.
I opened the charger and found this.

Here is a close up of the offending part.


This is what the charger looks like,Just like every other cheep charger.



So beware of cheap chargers and always babysit them wile charging and check them with a mutimeter as they are charging, just be careful not to short any thing. I have since received my Nitecore charger i4-v2 and it has not blown up yet. :beer:
Ed
 
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Smeerworst

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Maybe the charger helped you with not letting the (perhaps cheap?) battery explode, thus this componement burned out instead of the battery exploding ^^

3.1V is kinda dangerous for a 18650 cell to charge ?

But anyway's...... I love my Nitecore charger i4-v2 aswell ;) (wanted to do a review for it)
Got it for a few day's now and love it :)
Better save then sorrow.
 
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Livinloud

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get the nitecore i2 or i4 charger......this will never happen with quality products. ive warned people about these chargers before but glad i can see the insides of them now. thanks for sharing :beer:
 

Eudaimonium

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3.1V is kinda dangerous for a 18650 cell to charge ?
Wat.

Where did you get that from?

You're pretty much free to charge and discharge lithium batteries however you like. It's why they're in cellphones and other devices that don't do well on strict feeding regiments.
 

Smeerworst

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Wat.

Where did you get that from?

You're pretty much free to charge and discharge lithium batteries however you like. It's why they're in cellphones and other devices that don't do well on strict feeding regiments.
When a 18650 cell is below a certain voltage ''discharge'' it is dangerous to recharge it again, may end up exploding.

Cellphones flashlights and other devices have safety build in :) A laser doesn't nor do unprotected 18650 cells.

Candlepower forums is full of topics :)
 
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Eudaimonium

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Lowest voltage for lithium ion cell to go to safely is at 2.7 Volts or somewhere around that. That's considered an empty battery and needs a recharge.

I've successfuly revived a few cells that were at 2.0 or 1.8 Volts, by putting them in the charger and repeatedly connected-disconnected them by the terminals by moving it slightly, so the initial charge sets in, and charger "accepts" it.

How is 3.1 Volts supposed to be dangerous to charge? It's well within operational parameters.
 

Smeerworst

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Lowest voltage for lithium ion cell to go to safely is at 2.7 Volts or somewhere around that. That's considered an empty battery and needs a recharge.

I've successfuly revived a few cells that were at 2.0 or 1.8 Volts, by putting them in the charger and repeatedly connected-disconnected them by the terminals by moving it slightly, so the initial charge sets in, and charger "accepts" it.

How is 3.1 Volts supposed to be dangerous to charge? It's well within operational parameters.
Voltage/remaining capacity - A rough guide, not a set-in-stone rule.

4.2V = Full
4.1V = 90%
4.0V = 80%
3.9V = 60%
3.8V = 40%
3.7V = 20%
3.6V = Empty
(voltage is measured open circuit, the DMM leads on the poles with no load on the battery)

Quote from Candlepower forums

CPF said:
Batteries store energy, and stored energy, under the right circumstances, can be dangerous.

Most people use Li-Ion batteries in devices that are designed around them, and the circuits in these devices have protection built in to insulate the average user from the dangers associated with the batteries. Taking some single cells and putting them into use in a flashlight that does not have these safety circuits designed into it exposes the user to an additional level of danger.

When you use cells that have a protection circuit built in, you still have to be cautious with their use, but when you use bare cells, you are the protection circuit. There is nothing backing up your decisions, and if you make the wrong decisions, there can be consequences beyond simple cell failure.

If you understand the parameters involved in Li-Ion technology, and are diligent in monitoring, you can use bare cells and will not have any issues. However, if you have a lapse in diligence, you will have to pay the consequences.

On the other hand, if you use protected cells, a lapse in diligence simply results in the protection circuit kicking in.

When starting off with Li-Ion cells, I always recommend doing a run time test. Once you have an idea of how long the light will run on a fresh charge, you can simply keep track of how much you use the light and charge it before it becomes completely discharged. If you loose track of how much you have used the light, pull the battery and charge it up and start over again. Or, simply measure the open circuit voltage to get an idea if it needs to be charged.
To put it simple... Li-Ion cells are safe, when maintained properly, doesn't have to be the chargers error is all i'm saying.
 
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Eudaimonium

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You sure? Because I swear I had read that 2.75 Volts is minimum capacity, that is, empty, somewhere once. If I am not mistaken, 2.7 V even says on the battery itself sometimes.
 

Smeerworst

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You sure? Because I swear I had read that 2.75 Volts is minimum capacity, that is, empty, somewhere once. If I am not mistaken, 2.7 V even says on the battery itself sometimes.
I guess that all depends on the cell itself and what the manufacturer put's up.
 

Antharak

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Li-ion empty discharge voltage is 2.7 volts.

Go here and read.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
:beer:
 
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Smeerworst

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Li-ion empty discharge voltage is 2.7 volts.

Go here and read.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
:beer:
Yes but my point is, that you measured the battery not before you putted it in the charger, but once it was in..
 

Eudaimonium

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That article states that it becomes potentially dangerous to attempt to charge a cell which was at 1.5 Volts or lower for longer than one week of time.

Also, your percentages are off, article states 3.80V as 60% charge.

Therefore, I'll conclude that charging at 3.1 volts is completely safe.

EDIT, Addendum
It says that usually minimum voltage to preseve cell's life is at around 3.0 Volts, and apsolute minimum of 0% charge is 2.5 Volts. And it confirmed by point of 2.7 Volts being the cutoff voltage where protection circuit kicks in.
 
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Antharak

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Yes but my point is, that you measured the battery not before you putted it in the charger, but once it was in..
I can see how you would think that, I fixed the sentence. Sorry.
I checked it before I put it in the charger.
 




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