ZL SC600 TURBO MODE TEMPERATURE

Last night, for the first time I tried my SC600's turbo mode. Factory claims a step-down into HI after about 5 minutes. At about the 2:57 minute mark, I have to turn off the light since the head of the SC was uncomfortably hot already, up to about 2/3s of the body.
Since it was nearly scorching hot already, I presumed the remaining 2 minutes will no longer be 'safe' for me and the light. Is this normal for this particular light to get so hot? I always use my light very sparingly, just for the fun of it. Btw, I used an old, unprotected laptop cell LG abc18650 2800mAh. The cell was mildly warm. Feedback from you guys would be greatly appreciated. All rise, SC owners!
(I used the same cell in my Klarus XT11 and it stepped down from the turbo mode at exactly 2:58 minutes, light very mildly warm).
( If this hot temperature is normal in an SC's turbo mode, I won't take it as a problem)

Mind gets hot as hell too. To the point where if I hold it tight in my hand after it's been on for a few minutes, it can actually start to hurt and cause discomfort.

FYI, using a AW 3100mAH 3.7v 18650.

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Its very normal and i've gotten used to it. But if the air is cool enough(under 15C) then it won't get hot. The SC600 has a semi direct to copper bonding, so the outside temperature is close to the temperature of the LED star (the LED is hotter), so if you can hold it without dropping it, it should be fine, as the XML can tolerate a junction temperature of 160 degress before losing output permanently.

yifu said:

Its very normal and i've gotten used to it. But if the air is cool enough(under 15C) then it won't get hot. The SC600 has a semi direct to copper bonding, so the outside temperature is close to the temperature of the LED star (the LED is hotter), so if you can hold it without dropping it, it should be fine, as the XML can tolerate a junction temperature of 160 degress before losing output permanently.

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Have you tried using the turbo mode until it steps down? If so, how many minutes? I can't imagine how hot it would be...

Your skin perceives "too hot" at approximately 110º F, well below what the light would consider to be "Too hot".

At approximately 120º, your nervous system is deigned to initiate pain response, as scalding of the skin occurs a little over that....so about the time your nervous system is saying "Let GO!!!" the light itself is fine (If it survives the fall, etc...) as it can get a lot hotter w/o you worrying about it.

The circuitry will step it down based upon what the LIGHT feels is "too hot"....albeit, it is not able to detect blisters forming on YOU.



Its like a car engine...the manifolds, etc, get hot enough to burn you....but the car is designed so there is distance and insulation between the hot parts and you.

In a smaller, lighter, racing car...the driver might be exposed to crazy high heat from the engine and exhaust, transmission, etc....as its built for speed, not comfort.


Its the same with lights.

Some are built for long cruises, with large amounts of mass for heat sinking, etc.

Some are pocket rockets...built for high performance in the smallest lightest package they can fit that light engine into.

They are built for lumens, not comfort.



If you get a Lotus, you can't complain its not as confortable as your Caddilac.

So, scalded hand or not, it's safe to go back to the water huh....

I've ran mine to step down a couple times now. It did get hot but not to the point of being painful.

I've run my Sc600 to step down on a few occasions with no problems. Now that the thrill of turbo has passed. I use turbo mode when I'm going into a dark space from daylight, for the first few min and then step down as my eyes adjust.

Hold it in your hand the whole time rather than leave it on the table then pick it up and let us know if it get as bad. Your hand gets a surprising amount of heat away from the light as I have found out running my TK70 in turbo for an hour.

+1 No doubt. Also you might try using a better cell and see if that helps. I wonder if the voltage sag (and the resulting amperage step up) might have anything to do with it. My SC600w doesn't get painfully hot...especially if I'm holding it the whole time.

Cataract said:

Hold it in your hand the whole time rather than leave it on the table then pick it up and let us know if it get as bad. Your hand gets a surprising amount of heat away from the light as I have found out running my TK70 in turbo for an hour.

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Colonel Sanders said:

+1 No doubt. Also you might try using a better cell and see if that helps. I wonder if the voltage sag (and the resulting amperage step up) might have anything to do with it. My SC600w doesn't get painfully hot...especially if I'm holding it the whole time.

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A friend of mine bought my AWs, so I don't have any left to try. I'm wondering if voltage cell quality can be a factor, although as I said I used the same old cell in my XT11 till stepdown with no 'abnormal' temperature rise. Acquiring these old laptop batt packs, breaking it apart, then DMM its voltage has become a new side hobby for me though. Try it and you could be hooked!

My SC600W gets hot, but not burning hot. I left it running on a table it until step down tonight. Room temp was 71. The light got up to 107.6.

edc3 said:

My SC600W gets hot, but not burning hot. I left it running on a table it until step down tonight. Room temp was 71. The light got up to 107.6.

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Where you able to get the approximate elapse time at step-down? Mine at about 3 min. was too hot to touch. I started to worry about the increasing temperature of the remaining 2 minutes should it reach step-down at 5 min. Btw, I forgot to mention in my initial post that at first I tried a Sanyo CGR18650 1800mAh OLD LAPTOP CELL, with this the first step-down occurred at 1min, 43 sec. Then trying the same cell again, it stepped-down at an early 37 sec. Could it be the voltage sag? Is the SC600 designed to step-down early if you use 'tired' cells? (take note that cell I used that got the up the 3 min mark (but was turned-off because of the heat) was an LG abc18650 OLD LAPTOP CELL 2800mAh)

edc3 said:

My SC600W gets hot, but not burning hot. I left it running on a table it until step down tonight. Room temp was 71. The light got up to 107.6.

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Just tested it again with the LG 2800mah cell (the one that got me to almost 3min, but turned off because of the heat scare). I left it running on the table and it stepped-down at
5 min, 3 secs. Thanks to you and the rest of the guys. The whole light was real hot though....maybe a thick heat sink at the neck could help

If you DO hold it, it DOES sink off more heat ironically.

Mine gets hot too, I have never run the light to step down yet. If I ever need to I will not hesitate, it does get a bit warm but it is still very much holdable.

SC600 turbo mode: Just tried another old laptop LG cell 2800mAh (with a remaining voltage of just 1.72v when dismantled from its housing, with 4v at testing) and it also stepped-down at exactly 5 min. and 3 sec.
And then 2 more old laptop Sanyo UR18650Y 2000mAh and both got to the exact 5 min, 3 sec mark. I'm impressed with the ZL's electronics consistency. If it steps down early, its the cell that can't take it. Just put it on the table if you can't take the heat!

I've run the light to step down a few time, mostly on a walk, and the temperature is noticeable but not uncomfortable. If you leave light on a table and pick it up on the 5 minute mark then it will get very hot. I agree that holding it in your hand considerably lowers the temperature and it feels better.

I've also tried to measure this supposition:
On the table, reading taken on the 5 minute mark


Flashlight held in hand, static, reading taken on the 5 minute mark


Same emissivity and ambient temperature in both cases.

The results say there is a 5 degrees Celsius difference between the two situations. The gap, surely, widens when walking because of hands movement.

I love those pics, Wreck3r

If you get a step-down too early, the driver detects that your cells are too low (could also be because of internal resistance) and steps down one mode. If you cells voltage is a little low, the driver will compensate by drawing more current (amps), therefore creating more heat - I'm just not sure how much more, though, we're only talking about a few amps here.

Even my SC51c gets fairy hot when I run it at max mode on the table for a few minutes, but just borderline to uncomfortably hot.

Wreck3r said:

I've run the light to step down a few time, mostly on a walk, and the temperature is noticeable but not uncomfortable. If you leave light on a table and pick it up on the 5 minute mark then it will get very hot. I agree that holding it in your hand considerably lowers the temperature and it feels better.

I've also tried to measure this supposition:
On the table, reading taken on the 5 minute mark

Flashlight held in hand, static, reading taken on the 5 minute mark

Same emissivity and ambient temperature in both cases.

The results say there is a 5 degrees Celsius difference between the two situation. The gap, surely, widens when walking because of the hands movement.

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Wow! Some nice thermal imaging you have there. Is it? I guess your hand absorbs some of the heat. In my earlier post, in some cells why did my SC stepped down much earlier (one at 1:43 and the next at just 47sec)? What is the reason for that?