Nitecore D10 hot after emitter swap

I've got two Nitecore D10's that originally came with XR-E Q5 emitters. I bought a couple Q4-5A stars from Dereelight and soldered them in. Now after extended runtime (30-45 minutes) they get noticeably warmer than when they were running the Q5's. One gets so hot it shuts down. I swapped the Q5 back in that one and it runs fine again and much cooler.

Is it normal for the Q4-5a emitters to run hotter than the Q5's?

Thanks,
Fred

I think it's normal, under same mA, the 2 led generate same watts of energy = light + heat, so lower Flux Bin will generate more heat under same current.

Well, you replaced a more efficient emitter with a less efficient one. That "extra" wasted energy has to go somewhere.

No its not normal. I do agree that it should output more heat but there is NO WAY it is producing enough extra heat to cause it to overheat. There is something else wrong.

A couple of troubleshooting questions:
Is the current going to the LED the same with both LEDs?
Did you use a thermal grease under the new emitter?
What is overheating? The driver or the emitter?
Does the whole thing get hotter or just the LED?

Thanks for the explanation. I knew the Q4 was less efficient than the Q5 but I wanted the warmer tint. I'll put up with the extra heat if I ever need to run it that long.

spencer said:

A couple of troubleshooting questions:
Is the current going to the LED the same with both LEDs?

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I don't have a meter to measure the current

spencer said:

Did you use a thermal grease under the new emitter?

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Yes, I put Arctic Silver 5 under the emitters

spencer said:

What is overheating? The driver or the emitter?
Does the whole thing get hotter or just the LED?

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I haven't figured out what exactly is the source of the heat. The whole body of the light is warmer with the head being the warmest. On the light that overheated and shut down I did remove the head and touched the + terminal on the driver. The terminal was uncomfortably hot, but not enough to burn my finger. The + terminal of the battery was not noticeably warm at all.

On the light that overheated I did notice a faint whine when it was running the Q4 emitter and was silent when I reinstalled the Q5 emitter.

With no meter I don't know what else to tell you. Good luck in trying to figure it out.

spencer said:

With no meter I don't know what else to tell you. Good luck in trying to figure it out.

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Thanks. I'll see what I can do about a meter. To get the measurement you're asking for would I desolder the + wire to the emitter and put the meter in series between the + wire and the emitter?

Yes. And make sure it is in the mode for measuring amps.

If its shutting down , its because the driver has thermal protection and the heat is getting to the driver ..

Same thing happened when I put a XP-G R5 in my Akoray , put the Q5 back and no problems .

Hi FAM,

I am asking to myself, (What am I doing, it is not a good mental sign )

Q1- Can Arctic Silver 5 cause this?
A1- Yes, it could be. Because Artic Silver is electrically conductive. How?
*- Artic Silver is smeared on led side of pcb and adding resistance between LED legs
*- Artic Silver cause a contact between the LED (+ or -) and the flashlight body/pill

Q2- If it is not caused by artic silver, or Why two of my mods getting hotter?
A2- [Round 2] LED PCB could be defected,or LED mounted on PCB defectively.

Q3- A1 and A2 is not the solution, what could it be?
A3- [Round 3] These two LED's could have very low/high Vf which causes the driver work weird?

My 2 cent
EpRoM

I changed Q3 5C to my D10 (Q5). I turned the light on and it shut down after 2 minutes. The light was hot and I let it cool. Turned the light on and the same thing again.

The final result of the emitter swap was a burned D10. One SMD with a marking '14' melted. What is that and do I find it from a typical electronics store?

What does the SMD look like? i.e., how many legs if any, what color is/was it?

Edit: just looked at my D10 and I see a single black w/ white band component on it with the number 14, located next to the button. It looks like a diode or capacitor. Not sure what size/value, though.

I agree with eprom. I had a D10 that went into thermal shutdown when using a Q3 5A (on max or very high). I changed LED and now it runs fine.

I'm not sure, but I believe the D10 must use a constant power circuit, so an LED with lower vF could cause a large jump in current (and hence heat).

If it does use a constant power driver then that still wouldn't cause it to get so hot. Because 1W of heat at 350mA is the same as 1W of heat at say 500mA. I constant voltage driver would be different though.

Winx : Did you manage to fix your D10 ? I have same problem.

Vbeez said:

Winx : Did you manage to fix your D10 ? I have same problem.

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No.

Sorry, I've wrote about wrong smd :sick2:. I took a few pictures with USB microscope.

Burned D10 Q5, "AG3E 13" or something.

EDIT: AG3E seems to be 500 mA Synchronous Buck Regulator. Some info at german Messerforum.net.



Working D10 R2, maybe "AGGA 16".



Here's weld splatter from the lens of a burned D10.

Winx said:

Burned D10 Q5, "AG3E 13" or something.

EDIT: AG3E seems to be 500 mA Synchronous Buck Regulator. Some info at german Messerforum.net.

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Actually, the 500mA buck regulator you linked to uses a different package (10-lead MSOP). I believe the chip that blew is actually a BCX70G NPN transistor (also called NPN Epitaxial Silicon Transistor) (Datasheets). The BCX70G is marked "AG" and uses an SOT-23 package (3 leads) like what's in the photo. You can get them from Jameco (call them first to verify compatibility with original BCX70G) for 2.9 cents each (min order 10) + shipping. Mouser has them too, but they're out of stock and won't arrive until next March or so...

Don't take my word for it though... if I was perfect, I'd be paying someone to type this for me.

Are these devices worked harder with 3.7V or 1.5V input?

The magic smoke has been released. :tinfoil:

Winx said:

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Going from a Q5 to a Q4 should not cause any problems heat wise, if both LEDs have the same vf, and are drawing the same current. Can you check the vf of the Q5 and Q4?

Bill