Ebay Cree lights - poor quality battery pack

[S.Giles]

I just want to share an experience I had purchasing this Cree front light on Ebay.

The light itself is actually really good, but I noticed the brightness was intermittent, so after eliminating all other possible causes, I dismantled the battery pack and found the following:

Two dummy batteries, not even connected (but sneakily made to look like they were).

Two reclaimed laptop batteries, one of which was faulty (and causing the intermittent problem). They were covered with heatshrink which made them look newly-manufactured.

Having re-wired the battery 'pack' (now containing one battery!), everything is working well. I've tested the set-up and have a duration of well over one hour of bright light (which is more than enough for my commute) .

BTW, I discovered all this the day after leaving the seller good Ebay feedback! I'm seeing the funny side of this, having acquired a decent (if not 'as advertised') front light for just over £14. Caveat emptor.

Steve

 

[Scoosh]

B. Do not disassemble the battery pack, so as not to affect product performance and safety hazard.

Now we know why !

 

[S.Giles]

Now we know why !

That's funny. I hadn't noticed that.

 

[T.M.H.N.E.T]

I feel sorry for Cree, all they do is sell LED chips and circuit boards.

The quality of the light and battery thereafter isn't their problem

 

[S.Giles]

I feel sorry for Cree, all they do is sell LED chips and circuit boards.

The quality of the light and battery thereafter isn't their problem

Yes, my light has 'Cree' silk-screened on it by the Chinese distributor. Probably a trademark infringement, but I doubt they care.

I would imagine the lights themselves are manufactured by a different (ie, reputable) company, and bought in wholesale by the shady lot who put together dodgy battery packs and flog them as a package on Ebay. As I mentioned above, the actual light is pretty good.

 

[Nigelnaturist]

I have two packs both have seemed ok, both last 2+ hrs on full the original one i got I did test to nearly 3hrs on mainly full (95% of the time), not tested the newer one to the same extent, I tend to have one charged in the saddle bag, and charge the other when I have used it, I switch them round from time to time.

 

[S.Giles]

I have two packs both have seemed ok, both last 2+ hrs on full the original one i got I did test to nearly 3hrs on mainly full (95% of the time), not tested the newer one to the same extent, I tend to have one charged in the saddle bag, and charge the other when I have used it, I switch them round from time to time.

Hi Nigel,

Maybe you (or someone else) could answer a question about these lights and the battery packs that power them. My light came with a 4.2V charger and battery pack. Most (of the same type of light) come with an 8.4V charger and battery pack. This would suggest that the battery packs are usually wired in series-parallel (2 x 4.2V). Mine was wired in parallel-only (hence the 4.2V output). I can't imagine how bright my light would be if it was run at 8.4V - it is certainly more than bright enough at 4.2V. What's going on here? I'm a little confused!

Thanks,

Steve

 

[tincaman]

Hi Nigel,

Maybe you (or someone else) could answer a question about these lights and the battery packs that power them. My light came with a 4.2V charger and battery pack. Most (of the same type of light) come with an 8.4V charger and battery pack. This would suggest that the battery packs are usually wired in series-parallel (2 x 4.2V). Mine was wired in parallel-only (hence the 4.2V output). I can't imagine how bright my light would be if it was run at 8.4V - it is certainly more than bright enough at 4.2V. What's going on here? I'm a little confused!

Thanks,

Steve

Its ok, 4.2 v won't reduce the output initially although there might be some dimming as the voltage on the cells reduce, the packs and lights at 4.2v can use a simpler less efficient current regulator, also there are no cell balancing issues to worry about.
The 8.4v system used a more efficient type buck regulator but also have to account for cell balance, there will be no appreciable dimming over cell voltage reduction.
The led is not direct drive, ie the full cell voltage is not applied directly to it but through a small circuit board first, this regulates voltage and current. 8.4v applied directly would just fry the led

 

[gbb]

Reasons a manufacturer MAY use dummy cells are sometimes quite legitimate, perhaps to utilise a case type thats larger than the actual requirement of the piece of equipment its supplying.
As tincaman says, the circuitry of LED lighting regulates the voltage to the LED itself, I run a Cree setup with a 4x 18650 cell pack. It'll run equally as well witha 2x cellpack, as long as the supply voltage is higher than the minimum voltage required by the circuitry.
I use reclaimed laptop cells quite successfully, very cheaply and while some dont recomment tinkering with lithium cells, 1ive had two packs running without issues for 3 or 4 years now. Those cells came from defective laptops. In a pack, there may be 12 cells, but once a couple die, the pack becomes useless, but the other 10 cells are perfectly ok.
Its not recommended though...although I do use a good quality self regulating charger, not one that just dumps power into cells without monitoring them.

 

[Cycleops]

If the Chinese can sell poisonous baby milk they can certainly try to palm people off with sub standard and potentially dangerous batteries! With lithium batteries if they discharge below a certain level they will swell up and may catch fire. Best to buy from a reputable supplier.

 

[Bobby Mhor]

If the Chinese can sell poisonous baby milk they can certainly try to palm people off with sub standard and potentially dangerous batteries! With lithium batteries if they discharge below a certain level they will swell up and may catch fire. Best to buy from a reputable supplier.

Cree lights, horsemeat in our burgers, yon stuff in our chicken and on and on and on....
the world's full of con artists...
just saying not digging...

 

[raleighnut]

What's that old saying....'buy cheap, buy twice'

 

[ufkacbln]

As above ..... is the few quid saved worth the overheating and bursting into flames during charging hazard!

 

[hopless500]

I have two packs both have seemed ok, both last 2+ hrs on full the original one i got I did test to nearly 3hrs on mainly full (95% of the time), not tested the newer one to the same extent, I tend to have one charged in the saddle bag, and charge the other when I have used it, I switch them round from time to time.

Same here

 

[huwsparky]

I spent many times more than these cheap ebay lights on mine. Hopefully for this outlay it will give me years of reliability and good light!

When I buy anything I weigh up the pro's and con's of cheap alternatives. Didn't see the value of skimping on something that I'm so heavily reliant upon. Especially when they are renowned for being of poor quality and reliability in the first place. Plenty of bad reviews on these 'eBay' lights.