KDLitker C8.2 flashlight problem (Low mode automatically brightens up)

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d_t_a
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KDLitker C8.2 flashlight problem (Low mode automatically brightens up)

I decided to try out a flashlight with XHP50.2, since I didn't have one using the LED type yet.  I went for the KDLitker C8.2 with XHP50.2 flashlight.

Just received my order recently. I only tested the flashlight when I first received it, to check that it worked. (it appeared to work, I just tested switching modes and didn't use it further).

So now, it's about 2 weeks later and I decided to test it out a bit more. I was comparing its brightness and beam with my other flashlights,  then the KDLitker C8.2 seems to be malfunctioning (I haven't tested it much yet).

 

When set to Low mode, it will immediately brighten up and not actually stay in Low mode.

 

What could be the problem?  (I have tried changing the battery with  good high-drain capable ones like VTC6)

Edited by: d_t_a on 05/14/2018 - 23:23
tatasal
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Perhaps it’s on Automatic Ramp mode? haha Beer

d_t_a
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Ok, so I showed the video to the AliExpress store where I bought the said flashlight, and they sent me the replacement driver. Just got the replacement driver a couple of days ago, and only had time to do the replacement. (Pardon my poor soldering skills, plus not-so-good soldering iron..)

Anyway,
(again, this is the KDLitker C8.2 with XHP50.2 neutral-white 4500K)

So, this is the replacement driver sent by LHT Flashlight Store (seems to be KaiDomain in AliExpress):
~~

(the driver is supposedly the “H1-A” driver)

after some tiresome desoldering & soldering (pardon I have poor soldering skills…), I got the driver installed:
~~

And now to test it… it seems to not be working properly either — the correct operation for the KDLitker C8.2 is Very Low-Low-Med-High (5%-35%-65%-100%).

However, in my case, it seems to have only 2 modes: Low-High-High-High (one low mode, half-press gets “High”, another half-press is still “High”, and another half-press still “High”, then another half-press goes back to “Low”)

Decided to measure the tailcap current, and it seems to be very high!
Low is 0.56A
whereas High is at least 10.78A (using Uni-T UT210E clamp meter)

Is the replacement driver also defective or maybe the LED itself has some problem?

BlueSwordM
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The driver has a problem obviously.

How are you getting 10A at the tailcap though?

You are at the limit of the boost converter, and getting upwards of 30W, not 18W with the stock driver.

d_t_a
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Is it due to my improper installation? Or could the LED have a problem in the first place that caused the driver to malfunction?

BlueSwordM
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Doubt it. Even with improper installation, it should reach 6A at max, not 10,5A.

That means there is a resistor which has the wrong value, meaning it pulls way too much current.

d_t_a
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BlueSwordM wrote:
Doubt it. Even with improper installation, it should reach 6A at max, not 10,5A.

That means there is a resistor which has the wrong value, meaning it pulls way too much current.

Is it possible improper soldering technique could damage the resistor? Just ruling out that the driver could be the problem, instead of my not-so-good soldering skills that could have damaged the resistor..