> why would you want to replace LEDs every few years?
The rate at which they’re being improved is awesome; the old saying “nothing gets old faster than computers except fresh fruit” could apply to LEDs too.
You likely learned about “three color receptors” for vision. Turns out there are four receptors.
We have that receptor. Dinoflagellates have the same receptor. It’s rather basic stuff to how life works, evolutionarily very old.
Life adapted to blue daylight skies a long, long time ago.
Looping back to the first question — one thing I often do is replace white LEDs with amber emitters, to use at night.
And those too have been improving rapidly as the market for sleep-protecting illumination begins to develop.
On the opposite side of some of this theory, if I have to work into the night cutting up a felled tree to clear a road or looking for a lost puppy, whatever, I don’t want warm white light making me sleepy!
Yep, Dale — light with the peak output right at the blue-green spike that “white” LEDs emit is the key to keeping you wakeful and alert.
I had a 7-year-old neighbor who discovered this himself, long ago. He told me he was sneaking his under-the-blanket late nighttime video gaming/reading using a blue LED penlight because it kept him alert.
Takes a couple of hours for most people after the last exposure to blue-green light before the body starts letting melatonin accumulate and sleepiness begins.
And it takes very little ‘white’ light to reset that 2-hour countdown clock.
I’ve read that the amber night lights are very helpful to parents who want their babies not to stay awake after nighttime feeding, too.
I definitely prefer light on the warmer side of neutral. I like the compact fluorescent bulbs for being energy efficient, but they start at a warm white and go to a harsh white. Glad led bulbs in nice warm tints are available at an affordable price now.
Indeed, there is. Blue light activates the IPRCGs, which tells the brain to make wakey-wakey chemicals. In most people. About 19,997 out of every 20,000 people, really. I’m one of those other 3. And, statistically, the other 2 are blind. So I’m … nocturnal. And morning people are weird.
Anyway, the smoke grenade pouch showed up and fits my SRK well. Shipping was stupid-fast too. I ordered on Saturday and it arrived on Monday. Considering USPS has Sundays off, that’s like one-day shipping.
I suppose it sort of fits my BST too, but it doesn’t slide in far enough to reach the bottom, and the velcro is a bit short for a good grip. It’s still usable, but not ideal… a shallower or wider pouch would work better. What this one really needs is a Q8.
Tint preference is personal for sure.
I like neutral for flashlights but in the home we have changed all white halogen and those annoying “energy saving bulbs” for LEDs after a few months of living here.
3700K and now I buy warm white from China and these match very well.
Candles give a yellowish light and dimmed during dinner or something it just is a nice atmosphere white cannot give IMHO
I found a likely problem with my Q8 when using short batteries like my solder blobbed 30Q's and BD's. I was testing the light output with 1 to 4 batteries, on both types mentioned above, when unexpectedly on 3 BD's the ouput was not better than on 2 BD's. And this is what caused it:
The springs are loosing tension which caused one battery not to touch the batt+ contact ring on the driver. This may be caused by the one battery test that causes quite some current through the battery spring. The springs are in no way collapsed, they look and feel ok, but they are a bit shorter than before. Perhaps the best solution (I think we want to be able to use these short batteries in the Q8) is the use of bigger springs (longer, thicker wire). Another solution would be a shorter battery tube, but that will limit the battery size range a bit.
So I tried to fix it by sanding the battery tube shorter. I thought that because the head falls fully over the battery tube that that was no problem, but unfortunately the threading on the battery tube has a hard stop at the end, so by shortening the tube I lost contact with the driver
So to fix that the nice plastic ring had to go and a copper wire was soldered on the edge of the batt- ring
And I got contact again. I get 5725 lumen on 30Q's, like before
Btw, here are the results of the light output on different numbers of batteries. I chose the 30Q because that will be the most widely used battery for the Q8, and BD’s because that is the only lower drain battery (but still pretty high drain though) that I have 4 of and solder blobbed. Outputs were measured after 30 seconds on the highest setting:
Some notes:
*on 1 BD battery, the LVP kicked in at 32 seconds (output drop)
*the output on 4 30Q’s should be 5700 lumen, as I re-tested later. Two possible causes: This test was done before shortening the battery tube, so one battery may already have had poor contact. And also I did not recharge the batteries after each 30 second run, just added a freshly charged one every time, so 3 out of 4 cells were already slightly depleted.
The springs loosing tension was something I was worried about, the first spring is much taller then the second spring. My guess is that with short batteries the second spring is not even being used, so all the current is flowing through the single main spring. 5A is enough to soften most springs and thus allow them to shrink.
I experienced this in some of my SRK builds during testing before I bypassed the springs.
The only real fix is either to make the inner spring taller or both of them taller to give more wiggle room. Or you can use a much heavier duty spring that can handle the current without sagging.
Wouldn’t bypassing the springs fix the problem? I haven’t done that yet for any light. If it’s a solution, what is required for the job* and is it any more “difficult” than solder blobbing cells? (solder blobbing is pretty easy)
Yes, bypassing the springs should fix it, although this is something that can’t be overlooked as the light would cease to work if left in stock form.
Bypassing the springs is not super hard but can get frustrating if your bypass wire won’t stay where you want it. You get better as you go. I now make the baypass a bit longer then needed and roll it over the edge of the spring to hold it in place.
Bypassing the springs is not what we want for two reasons:
The springs are limiting the current a bit, we are already close to the flat top of the output curve of the XP-L, more so than planned. Even more current will not gain a lot of output and does generate a lot of heat.
The springs are our fuses, the ultimate safeguard against battery shorts, i.e. they will prevent catastrophies when inserting one of the batteries the wrong way (they will collapse and contact is broken).
Hmm and if 1 o 2 springs go weak it could be that 1 or 2 cels are not making proper contact, uneven discharge, shorter runtimes. Yes this needs attention
Would a thicker spring over the small secondary spring fix it?
