The There Are No Stupid Questions Thread

The Cree leds tend to be the leds with best output and efficiency. But the last two years some other manufacturers have catched up on both and usually do that with better tint/CRI/tintshift than Cree, so using Cree leds makes somewhat less sense atm. Some types of led however are simply not available other than from Cree, i.e. the XHP70.2 is big, cheap, efficient and has immense output, there is little competition for that.

That sounds really interesting. I read more about Nichia. In this week I understand, that I truly in love with Nichia:) I hear that Zebralight use N. in their lights.
What about other manufacturers, they produced their light on Nichia?

So, I have 3 stupid questions (or simple ignorance) about LEDs!

1) does a XPL-HI CW (6500K) have that annoying yellow core when reflected on a white wall? I am using both XPL-HI (+–5000K) and XPL-HI NW/CW (maybe between 4000-4500K) and both have that yellowish core either on SMO or OP reflector.

2) dedoming an XP-L2 (maybe 5500-6000K), that produces an annoying green shift, will improve the beam erasing the shift or will it make it worse?

3) I am planning to mod a 14500 flashlight with a MTN 17mm DD driver with guppy3drv. I would like to mod it with a NW Led (4500-5000K) that is powerfull (for small turbo boosts) but that, at the same time, does not produce significant tint shifts. What would be the best LED for that?

Thanks in advance !!!

3) Luxeon V or Samsung LH351D

2) XP-L2 can be sliced but not dedomed. I do not know results of slicing the XP-L2.

1) I have no definite knowledge about that. I have had a bunch of flashlight modded 7A XP-L hi leds and some leds produce the yellow center, some do not, it is not related to host, type of reflector, or focussing of the led and no diffrrence can be seen when looking at the led, wether off or lighted. It is still a mystery to me.

Edited / removed.
I think I succeeded in asking a stupid question. :smiley:

djozz, thanks do much for the answers :slight_smile: All clarified my doubts!
Funny thing, I’ve been using the Luxeon V but didn’t thought it was one of the best on the specs I wanted!!

About the XPL-HI 7A, I guess I will order some from Convoy and check how they behave. I wanna try them on OP reflector not SMO, so let’s see if some stay still and do not produce that yellow “stain”!

Again, thanks for all the answer and the correction about “slicing” vs “dedoming” :wink:

I have one question: will strong magnets be harmful to li-ion batteries if they are stuck together for long term?

A couple questions about batteries:
I do not vape or make my own powerwall etc so much of the information on 18650 cells seems conflicting or not relevant.

I have 4 unprotected button-top Samsung 30Q used just for the BLF Q8.
I just purchased these KeepPower IMR button tops to use when the 30Q are charging.

Are they protected? Are they a good/OK choice for the Q8?

I have a few protected cells that came with lights such as Sofirn, Thorfire, Folomov, etc. 2600-2800 mAh. I lend and gift these sort of lights to co-workers and family (adult children) when they show a genuine interest and a willingness to charge a light.
I am running out of those but I have some Panasonic flat tops NCR 18650B 3400mAh that are unprotected. Would you trust a muggle with an unprotected cell and the cheap usb chargers that usually come with a bundle?

I opened two laptop batteries from ones with broken screens and found:
Sanyo UR18650A rated at 2100mAh- I have been using in a Convoy S2+ (6x7135) and they work fine.
Panasonic CGR18650C rated at 2150mAh- I have been using in a Thorfire VG-10S and they do not last as long, or get as bright, but seem OK.

I would like to get a way to discharge/analyze them so I know the resistance and capacity, but for the price i could buy the Convoy L2 I have been eyeing with two 26650 batteries.
I am just using them and assuming they have half the rated capacity which is good enough for my everyday needs with these lower drain lights. I will never use them in series or in a high drain light such as Emisar D4. Any issues?

Stick with the 30Qs for the Q8, as they work very well.

If the light itself has LVP, why not? Nb: some lights just warn of low-voltage, but don’t turn off, so make sure of that first.

Cheap chargers might at worst shorten the life of the cell if it overcharges, but don’t expect it to burst into flames or anything.

Not really. I’m not paranoid about Li-cell safety, just practical, but I still use laptop pulls that are half their rated cap, or less, and never had an issue.

1. The 5000K has the ugly yellow corona

2. Slicing the Xpl2 5000K with a razorblade gives the exact beam pattern of the XPL hi, but it reduces output dramatically (30% or so) the 5000 K shifted to approx 3700 K

Picture shows xplhi 4B vs DD sliced xpl2 5000K

How do I post an item for sale? Imalent DX80?

Thank you.

Why can't manufacturers machine one more slot in their 1AA's so the clip can be reversed?

I'm really partial to the 1AA for general EDC. It's convenient to be able to reverse the clip if needed to attach a light to a cap's bill.

It's aggravating that many, otherwise great lights, can only orient their clips in one direction.


Here is one for you :beer: and you don’t need to reverse the clip, it’s a 2 direction clip :beer:\_encoding=UTF8&s=hi

I know what ZWB2 does. What I want to know is what it means. Is it an abbreviation?

I am having issues with PM… I responded toa PM but after sending, I don’t see my reply in the PM conversation thread…what gives??

Now that my laptop has been restored to good working order, my PMs are posting fine… head scratch… what a weird day.

Recent update from Windows 10 (Friday June 8th) bricked my laptop keyboard and touch pad drivers… now I’m stuck using the touch screen keyboard…

Here’s how it went:
10;30 pm while watching shows on Netflix with the kids, the windows update popped and ask for install and restart now or later… i chose restart later… finished Netflix, got too tired, went to sleep (closed the folded the screen down)… woke up to check email at 8am Saturday… no Windows log-in screen… no cursor on screen… keyboard keys and touchpad all unresponsive… had to log in with touchscreen keyboard (sucks crazy) and connect an external usb mouse… i checked the hardware drivers and it has issues… keyboard driver (ps/2 keyboard driver) has a code 10 issue and touch pad pointing device has a code 39 issue…
i have a Lenovo Flex 2-15…
tried uninstalling both drivers and rebooting several times to no avail… yes i tried rolling back the drivers, too… holding off on widows restore as a last resort…
Anybody have these issues, if so how did you fix?

Switch to Linux…

Naw, the damned thing kept ruining a work laptop, killing wifi completely. Know what a laptop is without wifi? A brick.

Kept rolling back, uninstalling drivers, etc., and that eventually got wifi working again, but slooooooowly. To finally stop its insistent attempts, I found the dir where it starts dumping new files in preparation for mangling the OS beyond recognition, ‘windows10upgrade’ or some crap like that, created a file with that name, and turned off all attributes, especially admin, to make it untouchable.

For a while I’d get popup boxes citing an “error”, as in not being able to create or write-to the dir, and it made me feel good. It eventually stopped trying.

You can try updating drivers with this:

I use it often when repairing people’s computers and it works great.

On the fenix rc40, there are two holes… anyone know what are there for?

1… lowest mode… i kind of see yellow spot… after lowest mode, no yellow…
2. All my xpl dedome have hint of green…
3. I dont know.