Exploding Battery pack - CREE XM-LT6 LED Bicycle Light

chick0

Bought a CREE XM-LT6 LED Bicycle Light on eBay from Hong Kong about a month back, used it about 6 times, i estimate i charged it 3 times, then on the 4th charge the Battery pack exploded, violently.

It was being charged at the other end of my house in a spare room where i keep my biking gear. They had been on charge for about 2 hours when i heard 4 loud bangs, but to begin with I thought they were coming from outside. I then went through to the spare room to check and found that the Battery's had exploded all over the room causing dents in the wall, smashing the bar adaptor they were plugged into and causing burns all over the carpet. From the look of the carpet burns i was luck not to have had a serious house fire.

As you will see from the pictures below there is very little left of the battery's or casing....

I know these Cree lights are often sold under various names, and are fairly popular due to there decent brightness and low price, a friend has exactly the same pack but his is called the SSC P7 or something...


Just thought i would give anyone else who has this pack or similar a heads-up..

DodgeT

Jees, you were lucky there. When I bought mine, I read where someone advised to charge / store them in a biscuit tin. Will make sure I do.

chick0

Yep bloody lucky there was not a house fire. I think if i had been in the room i would have noticed they were over heating and prevented the explosion, but you never know..

I have read online that putting a 1 amp shaving socket between the charger and the UK socket will give the extra protection against the chance of them over heating.

Biscuit tin is good idea, and charging them in less flammable location like a garage..

The Rookie

That will do nothing to help, it doesn't limit the current (you could just put a smaller fuse in your plug anyway) enough to stop an affected Li-ion cell going into runaway.

Not sure why you heard 4 bangs as only one cell appears to have gone?

The failure could be one of
1/ Defective cell
2/ Defective construction of the pack leading to overcharging of that one cell
3/ Defective charger passing too high a voltage to the pack.

Only number 3 will still be checkable I suspect!

chick0

The Beginner wrote:

That will do nothing to help, it doesn't limit the current (you could just put a smaller fuse in your plug anyway) enough to stop an affected Li-ion cell going into runaway.

Not sure why you heard 4 bangs as only one cell appears to have gone?

The failure could be one of
1/ Defective cell
2/ Defective construction of the pack leading to overcharging of that one cell
3/ Defective charger passing too high a voltage to the pack.

Only number 3 will still be checkable I suspect!

These packs are made of 4 individual Lithium batteries which are then housed together. If you look at he pics you can see the 4 cylindrical housings have all exploded, so im guessing that was the 4 separate bangs i heard.

It was a UK supplier of these Lights i contacted that told me to use a 1 amp adaptor in the future, he said that all of these lights that are officially sold in the UK should be sold with one, i have no idea if this true.

danlikesbikes

Thats thought mate, but at least its only an inanimate object and no one was injured is the important thing.

Have had something similar happen though not to the extend of a full on explosion though. Can be very hard to detect as these types of packs do run at high temperatures when on charge and think you would have struggled to know the difference between a hot charing pack and a hot and dangerous charing pack unless you have digital thermometer and know the safe operating limit.

My problem was caused by an arch across all 4, still not sure how this occurred but the manufactures best answer is either a degradation to one of the wires rubber coating inside the plastic unit causing a power arch across to the others. Or possibly where the cable was soldered to each battery in the back coming lose.

If you youtube them being made is quite easy to see how this could happen, though is pretty rare.

The Rookie

chick0 wrote:

These packs are made of 4 individual Lithium batteries which are then housed together. If you look at he pics you can see the 4 cylindrical housings have all exploded, so im guessing that was the 4 separate bangs i heard.

I know it has 4, 3 in the photo's look intact with just some dents, hence my comment, none of the pics seem show the other 3 as exploded at all, unless you have pics you haven't shared!

cookymonster

my 4 pack was charging in kitchen until i read this a minute ago , its now charging in the SHED !!!! :shock:

supersonic

Hope it's not a wooden shed ;-)

PashleyRider

Glad nobody was hurt, those batteries can really go with a bang! It may be worth investing in a LIPO charging bag in the future, these are fire resistant and should aborb any battery explosions.

I just received the same setup. I havent even bothered with the standard charger as it looks crummy+ I didnt have a UK plug adaptor. I am using an Imax B6 charger (commonly used with RC stuff) which detects when the batteries are full, along with a temp sensor on the batteries so the charger will automatically cut out if the batteries get hot. I made an adaptor so that the batteries link up to it. Annoyingly my batteries are shite, they are supposed to be 4400MAH but only charge to 2000MAH and do approx 2 hours, suggesting they are old stock as lithium ion batteries deteriote over time. I'm looking to convert to a LIPO battery and running a low voltage cutoff to protect the battery.

bennett_346

As good as they are this is the reason i bought Electron Terra 2 lights last year. Big decrease in light output but i do feel a lot safer.

WindyG

The reason this happens is because it's using an adapter and not a charger, the adapter will be cheaper and unregulated so will be putting out more power than is need, regulated ones are more expensive. I doubt the light will have a charging circuit so no way of detecting correct charge and limiting so basically it's too much power for too long until you unplug or it goes bang. You need at min a regulated adapter but ideally a charger which will step down the voltage as the battery charges up and trickle charge.

kenan

Would one of these work: http://www.magicshine.co.uk/accessories ... 012uk.html ??

PashleyRider

It may need a different end connector (i'm not familiar with magishine, looks just like the light the OP listed) however the specs are fine for the battery (it'll charge the batteries in 1.8x the time of the standard charger but any 8.4v battery over 1800mah can take it)

The Rookie

PaulOliver wrote:

Annoyingly my batteries are shite, they are supposed to be 4400MAH but only charge to 2000MAH and do approx 2 hours

Something wrong there, my dealextreme ones manage and easy 4 hours on full power....

PashleyRider

Are yours the 4400? Or the 6500? I emailed the seller, no reply yet funnily enough! I have been charging the pack and running it down once a day to see if it improves (some batteries get better with use, no luck yet)....see how that goes!

chick0

The Beginner wrote:

PaulOliver wrote:

Annoyingly my batteries are shite, they are supposed to be 4400MAH but only charge to 2000MAH and do approx 2 hours

Something wrong there, my dealextreme ones manage and easy 4 hours on full power....

The battery pack that exploded lasted 4 hours+ on full beam.

The Rookie

PaulOliver wrote:

Are yours the 4400? Or the 6500?

Not sure to be honest, came from DX about 18 months ago....

PashleyRider

Weird, were your batteries not so great to start out with and then got better? My batteries capacity has increased from 2000mah to 2500mah now after 4 cycles which is still way off the claimed 4400mah!

camerauk

cyd190468 wrote:

The weird thing is a 20 cent polyswitch in the battery pack would have prevented this. Maybe people with similar battery packs should retro-fit one.

any idea which one we would need to do this and where would we fit it?

Cheers

Northwind

If you're concerned, you could invest in a charging bag like model racers use. Though that won't help if the charger goes on fire, as they occasionally do with the very low quality ones.

What's interesting about it to me is that the fairly random nature of the products means that just because one blew up it doesn't mean another one isn't perfectly safe- if it was a consistent product it'd cast doubt on them all but I've had 3 lights like that and they all had different battery packs, different chargers, etc. Which isn't helpful at all tbh but variety is the spice of life

cooldad

I stick to decent chargers - Xtar are good and pretty cheap, and batteries from local guys like Torchy.

turbo1191

I just received a kit the same as this but ordered through amazon. All the contents are the same and checked the charger and it seems to be a 1amp.. haven't used either yet but thanks for the heads up. Will be charging it somewhere out of harms way..

p44cmb

I have this exact light and so far have not had any explosive issues such as yours. I've been using it since around October and charge it probably twice a week. I'm going to keep a closer eye on it from now on.

sellisnba

Slightly off topic here, I have one of the Cree t6 lights but the 'o' ring handlebar mount is crap!
Does anybody know where I can get a sturdy mount or how to make one?
I hope mine doesn't explode, it came from a uk seller with a uk charger as well.
Ta

Greer_

sellisnba wrote:

Slightly off topic here, I have one of the Cree t6 lights but the 'o' ring handlebar mount is crap!
Does anybody know where I can get a sturdy mount or how to make one?
I hope mine doesn't explode, it came from a uk seller with a uk charger as well.
Ta

http://www.chainreactioncycles.com/Mode ... elID=23533

Manc33

There's also this holding bracket, probably not built like the Hope one but this is a straight fit I think (a review said the Hope one needs a bit of plastic sawing off and you need a longer screw). UK seller with 99.9% feedback.

http://www.ebay.co.uk/itm/Swivel-mount- ... 43c28d0040

The charger I got with my cheap Cree kit...

Model: HDWY-0841000
(its a US 2 pin one with a UK travel adapter)

Output: 8.4v @ 1000mA. So if that can only put out 1000mA does that mean 1amp and it is safe? :roll: Don't know one thing about electric. :oops:

I wanna know what OP's charger says it outputs. :?

homers_double

I think this thread justifies my Lumicyle lamps and an exposure head torch.

Yes they cost a tidy sum but then again they don't explode in the house.

CitizenLee

homers double wrote:

I think this thread justifies my Lumicyle lamps and an exposure head torch.

Yes they cost a tidy sum but then again they don't explode in the house.

I was thinking the same about my MagicShine MJ-880s... they weren't cheap but I have peace of mind that I can put them on charge and not worry about them going bang!

I do love a bargain but I've had enough dodgy Chinese electronics over the years to know when it's better to spend a little extra.

I'll probably get grief from all the people who do have perfectly working lights from HK, but if that's the case I'm happy for you

Ouija

It's got nothing to do with the chargers, it's the lithium ion batteries that have a capacity to explode. Any Li-Ion battery can do it, irrespective of make, model or type (though some manufacturers go to greater lengths to prevent it than others). That's why they opted out of using them in the new Airbus (or was it the Boeing one, i forget). The Li-Ion batteries in your laptops can explode and so can the ones in your uber expensive torches, I-Pads, I-Phones etc unless steps are taken to prevent it.

homers_double

Well yeah, but I would expect the likes of Apple to go to those lengths. Thats why I don't buy cheap shit and live a care free life.