Ultrafire 18650 3000mA exploded

[Monocrom]

Best 18650 cells = AW brand protected cells.

Best rechargeable RCR123 cells = AW brand.

Best charger = PILA IBC model (And I mean by a very wide margin.)

Best primary CR123 cells = Any Made in the USA cells (SureFire, Panasonic, Streamlight, Duracell, Energizer, Rayovac.)

Best way to save money on CR123 primaries = Buy online (from a respected dealer), buy in bulk, buy Made in America cells. The first two in order to save money. The last, in order to make sure you are getting quality cells that are not cheap & dangerous junk that might explode.

Hope this helps.

[Bajades]

A friend of mine had a single battery 18650 protected cell flashlight running a single P7 LED (Aurora AK-P7) explode/catch fire while in his flashlight holster. When it blew there was a loud pop, the tailcap blew out and caused a small second degree burn to the inside of his forearm. I don't know the brand of the battery (came with the flashlight-marked ICR 18650 2400 mah), but disecting another identical battery showed it did have a protection circuit at the base of the battery. The battery was charged with an inexpensive single cell Li-Ion charger that came with the flashlight. What would have caused a single cell protected battery to explode? Seems to me the protection circuit must have failed in this case? Still, what would be the explosion mechanism?

[SilverFox]

Hello Bajades,

Welcome to CPF.

It is possible for the wiring that connects the protection circuit to the cell to short out. This doesn't happen very often. This could cause the cell to heat up and pop.

The most common cause of this is rough service or rough handling. This results in physical damage to the cell.

Tom

[DavidMB]

Very interesting thread. I've seen some new lights on the market that take 4 18650.. That's like holding a bomb. But,, I think not so much if one buys a good charger and good quality batteries.

If someone did buy a unprotected Li-ion battery's and has a light without a low voltage cut off, what would keep the batteries from discharging too low and ruining the cells? Do you just have to guess when to recharge?

[aimxplode]

Very interesting thread. I've seen some new lights on the market that take 4 18650.. That's like holding a bomb. But,, I think not so much if one buys a good charger and good quality batteries.

If someone did buy a unprotected Li-ion battery's and has a light without a low voltage cut off, what would keep the batteries from discharging too low and ruining the cells? Do you just have to guess when to recharge?

Use a multimeter or voltmeter to see what the charge status is at. I use the voltmeter that is sold in the CPF Marketplace by "cottenpickers", its extremely easy and convenient. Here is a pic of it:




4.2V = 100%
4.1V = about 90%
4.0V = about 80%
3.9V = about 60%
3.8V = about 40%
3.7V = about 20%
3.6V = empty
<3.5V = over-discharged

[DavidMB]

Nice volt meter! So that's the only way? to carry around a portable voltmeter, or just guess?

[Monocrom]

Never guess with these types of cells. You don't have to carry a voltmeter with you. You should test the cells often. Not so often that you need to EDC a voltmeter. But if you feel that guessing will become a real possibility . . . Don't use 18650s or similar types of cells.

Some flashaholics rely only on AA or AAA rechargeables for their uses. Or, they rely on older rechargeable models; such as a SureFire 9AN for example.

[andrewnewman]

General rule(s) of thumb:

1. NEVER just guess.
2. NEVER use unprotected 18650 cells in a multi-cell flashlight.
3. If you use unprotected cells in a single cell light with low-voltage circuit, I would make absolutely sure I knew what the low voltage indicator was. Some cells ramp down to a lower level, some flash or beacon periodically, some go suddenly dead (like a protection circuit was triggered) and some do combinations of these.

One further observation is that even with a single cell light, it's particularly risky to use an unprotected cell (IMO) with lights that have a wide voltage range such as 0.9V - 4.2V. These are popular because they can use different chemistries but can really do damage to a LiIon cell trying to get that last electron out before the user notices. By contrast, my Malkoff M61 drops out of regulation around 3.4V under load. There is a nice slow and visible dimming between 3.4 and 3.1V. After 10 minutes the unloaded voltage will bounce back up to 3.5-3.6V. You really have to be paying no attention to manage to trigger the protection circuit. Having said that, however, I still use protected batteries in my Malkoff. Who knows when I might doze off with the flashlight on

[aimxplode]

Nice volt meter! So that's the only way? to carry around a portable voltmeter, or just guess?

Are you using a single cell 18650 light, or a multicell one?

[DavidMB]

I use 14500 in my light. I'm trying to figure out what daily or weekly procedure people use keep the voltage from dropping too low (because testing often seems like a chore) using unprotected cells, (any type).

Do you have to get out the voltmeter every so often and test it or maybe do some people get a feel when to pull the battery recharge it before it drops too low..

Seems like one slip up could ruin an expensive cell.

[aimxplode]

I use 14500 in my light. I'm trying to figure out what daily or weekly procedure people use keep the voltage from dropping too low (because testing often seems like a chore) using unprotected cells, (any type).

Do you have to get out the voltmeter every so often and test it or maybe do some people get a feel when to pull the battery recharge it before it drops too low..

Seems like one slip up could ruin an expensive cell.

Use a protected cell so you won't destroy the cell if you forget and run it down too low. I just test mine whenever I feel I've used it alot.

[jirik_cz]

4.2V = 100%
4.1V = about 90%
4.0V = about 80%
3.9V = about 60%
3.8V = about 40%
3.7V = about 20%
3.6V = empty
<3.5V = over-discharged

This is not correct for new AW 2900mAh and AW 3100mAh cells. Or any other Panasonic NCR18650 based cells. They still have around 40% of capacity left at 3.6V OCV.

[alpg88]

If someone did buy a unprotected Li-ion battery's and has a light without a low voltage cut off, what would keep the batteries from discharging too low and ruining the cells? Do you just have to guess when to recharge?

basicly nothing stops from killing them by overdischarge, i use 6 unprotected 3s2p in inc light, i can see when bulb is getting dim and recharge needed, but with leds you often can't see when you need to recharge.

[aimxplode]

This is not correct for new AW 2900mAh and AW 3100mAh cells. Or any other Panasonic NCR18650 based cells. They still have around 40% of capacity left at 3.6V OCV.

Hmm, interesting. I'm using Eagletac 3100mAh cells, which use the NCR18650, and I was wondering why it reached lower voltage so quickly. Do you know what a new discharge table for the NCR18650 would look like?

[yifu]

Hmm, interesting. I'm using Eagletac 3100mAh cells, which use the NCR18650, and I was wondering why it reached lower voltage so quickly. Do you know what a new discharge table for the NCR18650 would look like?

The new 2900/3100s can be discharged safely down to 2.5V, but the older chemistries can only be discharged to around 2.75V. The discharge curve for the 2900mah NCR is posted here. At 3.6V the cell still has more than 50% of its capacity so you shouldn't start charging at 3.6v.
http://industrial.panasonic.com/www-...A4000CE240.pdf
You would notice that the cell only reaches maximum capacity when it's above 60 degrees celsius (or 140 F). Which is why i laugh when people say you shouldn't run a high powered light for too long and let the cells get hot in use or it'll cause explosions Or that once the battery gets above 40 degrees celsius it would explode. Temperatures above 50 degrees will actually net more capacity and the cell can survive way higher temperatures than 60-70 C. However, the only thing is that storing it at high temperatures will increase permanent loss of capacity to above 10% per year.

[aimxplode]

The new 2900/3100s can be discharged safely down to 2.5V, but the older chemistries can only be discharged to around 2.75V. The discharge curve for the 2900mah NCR is posted here. At 3.6V the cell still has more than 50% of its capacity so you shouldn't start charging at 3.6v.
http://industrial.panasonic.com/www-...A4000CE240.pdf
You would notice that the cell only reaches maximum capacity when it's above 60 degrees celsius (or 140 F). Which is why i laugh when people say you shouldn't run a high powered light for too long and let the cells get hot in use or it'll cause explosions Or that once the battery gets above 40 degrees celsius it would explode. Temperatures above 50 degrees will actually net more capacity and the cell can survive way higher temperatures than 60-70 C. However, the only thing is that storing it at high temperatures will increase permanent loss of capacity to above 10% per year.

I've heard that it was 2.5v was under load. So, the 3.6v you are talking about, is that under load or resting voltage?

[yifu]

I've heard that it was 2.5v was under load. So, the 3.6v you are talking about, is that under load or resting voltage?

Resting voltage. I was simply saying that if you recharge the newer NCRs at 3.6V resting voltage, you forgo about 60% of it's real capacity, which makes it a 1400-1500mah cell if that's fine with you... The truth is, with these newer cells, after the sharp drop from 4.2-4v, the resting voltage and V under load reaches parity and are nearly the same. Worse cells have higher internal resistance and that will induce a voltage sag, not seen with the NCRs.

[och]

Can 18650 battery explode if you insert it into the charger the wrong way? Or into the flashlight?

[Fusion_m8]

Can 18650 battery explode if you insert it into the charger the wrong way? Or into the flashlight?

If UNprotected 18650s and/or if the charger/flashlight does not have any active safety features such as short circuit/overheating protection. The answer is very much a "YES".

Protected batteries have a PCB or Protection Circuit Board that prevent short circuits, over discharging and over heating to occur. Some LED flashlights have in built protection circuits that shut down operation if over heating/discharging of the battery occurs or if the batteries are inserted the wrong way, however the majority of the LED/HID and incandescent lights have no such protection and the unprotected battery(s) can explode if inserted/connected the wrong way or overdischarged/short circuited.

[yifu]

Can 18650 battery explode if you insert it into the charger the wrong way? Or into the flashlight?

Won't happen with a protected AW cell. Although once the IC protection kicks in you would need a cold start charger to re-activate it.

[Patriot]

I own 4 x 18650 3000mah Ultrafire cells recently purchased from the Marketplace. I was going to test and dissect them but I'm probably not going to get around to it. If Lux Luthor or one of the other battery gurus would like to examine the 3000mah Ultrafire cells or put them to some testing, I'll be happy to mail them out. The one condition I would set is that some form of data make it back to this thread for the sake of education.

[bshanahan14rulz]

Do they all weigh approximately the same?

I just added a link in another post in this section about fake ultrafire 3000mAh cells, the link has a few pics of cell dissection. You will get a kick out of it:
http://www.candlepowerforums.com/vb/...=1#post3909627

[DM51]

Do they all weigh approximately the same?

The ones that have exploded weigh less afterwards, LOL.

[benthiccracker]

IMR 18490 by benthiccracker, on Flickr
So I bought these batteries brand new. I marked them and will rotate them. I have a 4 bay charger on the way. If I get a voltmeter/multimeter and check the batteries for over charge 4.2 V and over discharge <3.5 V I should be okay? I will be running them in a extended 9P overbore Zero Res switched with a Malkoff M91. SAFE?

• Brand: Trust Fire 4 bay Charger
• Model: TR-003P4.
• Input 1: 110V-240V 50/60HZ.
• Input2: DC 12V 2A.
• Output: 4.2V 4*500Ma.
• Constant Charge Current: 500MA ±10%.
• Constant Charge Voltage: 4.2V ± 10%.
• Cut-Off Current: 60MA ± 10%。
• Comes with protected function.
• Comes with LED charging indication.
• Size: 141*106*33mm.
• Plug Standard: US Plug.
• Compatible with 10430, 10440, 14500, 16340, 17670, 18500 and 18650 battery.

[benthiccracker]

so always be alert, check frequently each time you recharge to see if there is any damage on plastic wrapping and both terminal, if then light output suddenly act funny or you hear hissing sound, immediately put the light on vertical standing position then run away.

LOL! Run, Forest run! <Torch shoots off like a rocket>

[yifu]

Should be ok. From my experience with a Trustfire TR-01, it has a rudimentary CC/CV phase. And either way, LiMn cells have a lower internal resistance so it will terminate at around 4.23-4.25 volts with a Trustfire. That should be fine but it would be best to terminate under 4.2V. Also, IMR cells can be discharged down to around 3V without damage and regular LiCos can be discharged down to 2.5V without damage. Discharging down to 3.7v is just plain wrong as you forgo around 50% of the capacity for an LiCo.
Your setup should be very safe. M91s only draw about 850mA with 18500s so you should use regular AW18500s as you get more runtime. I have never seen a thread about an AW cell exploding ever before so you should be very safe.

[TEEJ]

IMR 18490 by benthiccracker, on Flickr
So I bought these batteries brand new. I marked them and will rotate them. I have a 4 bay charger on the way. If I get a voltmeter/multimeter and check the batteries for over charge 4.2 V and over discharge <3.5 V I should be okay? I will be running them in a extended 9P overbore Zero Res switched with a Malkoff M91. SAFE?

• Brand: Trust Fire 4 bay Charger
• Model: TR-003P4.
• Input 1: 110V-240V 50/60HZ.
• Input2: DC 12V 2A.
• Output: 4.2V 4*500Ma.
• Constant Charge Current: 500MA ±10%.
• Constant Charge Voltage: 4.2V ± 10%.
• Cut-Off Current: 60MA ± 10%。
• Comes with protected function.
• Comes with LED charging indication.
• Size: 141*106*33mm.
• Plug Standard: US Plug.
• Compatible with 10430, 10440, 14500, 16340, 17670, 18500 and 18650 battery.

+/- 10% on the charging range is large. 4.20v +/- 10% = 4.62 v to 3.78 v

So a pair of cells could come off at 4.62 v (OVER CHARGED), or, as low as 3.78 v (Not very charged).

As a rule of thumb, don't buy a charger that is named "Anything"fire.

Because it might set anything on fire.


There are decent chargers that are programmed to charge the cells more safely...and t make the cells last longer.

For example, its great that you'd measure the charge, but what if it IS 4.62 v?

The cell is already damaged proportionally...and if the extended tube is to run multiple cells in series...and the cells come of the charger with that kind of range of charges....how are you going to get matched sets?

The cells will constantly have different histories, different internal resistance, etc.

So, in a perfect world, I'd say just replace the charger with a real one...a Pila IBC (2 Bay), or an Xtar WP6 II (6 Bay), or another one recommended by the guys here who review these things.

It would work better for your application.

[benthiccracker]

+/- 10% on the charging range is large. 4.20v +/- 10% = 4.62 v to 3.78 v

So a pair of cells could come off at 4.62 v (OVER CHARGED), or, as low as 3.78 v (Not very charged).

As a rule of thumb, don't buy a charger that is named "Anything"fire.

Because it might set anything on fire.


There are decent chargers that are programmed to charge the cells more safely...and t make the cells last longer.

For example, its great that you'd measure the charge, but what if it IS 4.62 v?

The cell is already damaged proportionally...and if the extended tube is to run multiple cells in series...and the cells come of the charger with that kind of range of charges....how are you going to get matched sets?

The cells will constantly have different histories, different internal resistance, etc.

So, in a perfect world, I'd say just replace the charger with a real one...a Pila IBC (2 Bay), or an Xtar WP6 II (6 Bay), or another one recommended by the guys here who review these things.

It would work better for your application.

Jeeez, I need to start doing more homework before I spend $$$... Anybody wanna buy a "Start-a-Fire" 4 bay charger? Cheap! J/K don't think I would get any bites anyway on this thread...

[bshanahan14rulz]

The ones that have exploded weigh less afterwards, LOL.

Sure, they weigh less afterwards, but the air feels much heavier in your lungs, that's where all the weight goes ;-)

Take a look at the linky ;-) I think maybe the plaster filling would have made the difference in weight harder to notice, but there still ought to be a difference, right?

Not my picture, picture from the original poster at another forum: http://i.imgur.com/aPGyA.jpg

[Anzycpethian]

I don't know where else to post it but I have a question: When a lithium cell explodes inside a flashlight, isn't the aluminum tube / body of the flashlight enough armor to your hand to prevent most dangerous injuries?
Where can I find more information about what happens when a cell explodes inside a flashlight, like does the body explode in splitters or strongly dents?