Now What: Did my Luxeon3W@3,7V Li-Ion by eBay Died ?

[DonX_Fi]

Hello
The 3 wattager just died in my hand: I took Li-Ion of from Nano and put it into torch. The light was flicering and almost instanly started tint to blue and fade away. I put it off. And restarted it again. Same result. Light went blueish color and get fade away. I keept little pause some 5 min or so. I lit again torch: One flash and now it's true ' candle mode ' :-(
Not almost any light by led.
This was 4th. time to charge battery.
I can say, this torch was the brightes led lamp by me so on
Can U gimme some info, what was happend to my torch ?
----

Sorry my typo's, my writing English is not so good...

[lamperich]

Hello
The 3 wattager just died in my hand: I took Li-Ion of from Nano and put it into torch. The light was flicering and almost instanly started tint to blue and fade away. I put it off. And restarted it again. Same result. Light wet blueish color and get fade away. I keept little pause some 5 min or so. I lit again torch: One flash and now it's true ' candle mode ' :-(

Can U gimme some info, what was happend to my torch ?
----

no resistor to limit current.
thermal runaway happen



that´s one of the reasons why this paper exist.
http://www.hdssystems.com/LedFlashlightWhitePaper.pdf

by the way measure voltage or current doesn´t help you much. it´s bad enigneerd led torch.
not a surprise

[DonX_Fi]

As we see, there somekind of DC-DC invertter.

I'm not so good in electronics.
Here's damaged luxeon

I measured voltage on Luxeon, it was 3,7V.
I have spare luxeon emitter, maybe I will swap and try again...

[lamperich]

As we see, there somekind of DC-DC invertter.

ah a regulator :-(

also not a surprise.
what i learned here in CPF is if you want to drive one LED(specially Lumiled Luxeon1or/3) typical Vf between 3,1-3,8V
with 3 1,5V Alkaline
or 3NiMH
or one Li ion cell
a so called "Buck & boost" Regulator is needed.

Unfortunately they are not very popular because they are ugly inefficient60%(at least for now)

So this flashlight (nuwai Q3?) also works fine with one cr123a 3V Battery right? Some Boost regulator went into direct driven mode of Voltage(in) is higher then Voltage @ led.

i wouldn´t recommend you trying it with another LED! the risk is high
by the way what bin has the damanged LED?


There is a cheap & easy way driving a led with one liion rechargable.
Use a little resistor to limit current. 2 ohm 1/4W for example.
You will find more informations in the cpf electronic section.

[DonX_Fi]

Hi
I did replace Luxeon by some very cheap MXDL's luxeon swap. I did put heat transfer compund to bottom on luxeon. There was no id on both lux's.
I dont know brand of this torch. This was eBay finding.
It uses 3,7V Li-Ion recharchged battery.
Now it works.

[lamperich]

Hi

Now it works.

Hi Juha,

glad to hear
But i would highly recommend next time if you put the fresh charged rechargable in the torch measure current first.
it shouldnt be more than 1A. That´s already much. if the torchs becomes very hot when it´s on for a couple of minutes is also a bad sign.


This is a U/I curve created by one of the CPF members here.

what you can see is spectacular.
There are really EXTREM low Vf bins possible. 1,5A @ !>3,6V<! That´s pretty good for Constant power regulator like HDS but bad for a Voltage source like li-ion& NiMH rech.
Luxeon3 are rated @ 700mA
but there is more what you see is a so called Vf Shift. That means the blue curves is when the led was new. After only a few hours the Vf decrease (same led).



Usually "a regulator" should prevent exactly such a behaviour.

But maybe it´s only a stupid malfunction

shit happens