Heat Question

New to these (20th century) led flashlights and as she has steped out for the day I have been unboxing & starting to play with the ones that I just aquired. The one i'm first playing with is a zebra sc600w mk II l2. Note that I have an led flashlight thats appx 20 years old that uses 1-3 CR123's
and when using 3 CR123's the head of the light will get hot but not the body or the batteries. In using this zebra flashlight the entire body of the flashlight gets very warm nearing hot. Is this normal, & is this heat in the body of the flashlight from the battery heating up ? Thanx for walking me thru this.
V / R Dwayne

It's normal for the body to heat up with extended run times at a high output because the heat begins at the led which contacts the MCPCB which contacts the heatsink shelf which contacts the body. The battery shouldn't get hot unless you are running alot of amperage.

This is a Good thing. You want the whole body taking heat away from the emitter. A well designed flashlight will do this if output is strong.

Total output and thermal management are opposite sides of the same coin. More output =more heat. This should be of some concern for anyone investing money in this hobby, since excessive heat can shorten the longevity of the emitter. While I'm sure your Zebralight will be just fine, there are many super high output devices on the market today that are unable to effectively remove heat from the bezel. For me, heat sink and thermal management are primary considerations when selecting a light.

Having an entire light heat up is a good thing. It means heat is getting taken away from the emitter.

Do hotrodded high-output lets get really hot? yup. Does this shorten the life of the emitter? Probably... but who cares if the lifespan is reduced from 50,000 hours to 10,000? ... for us flashaholics, we're constantly moving on to the next greatest thing LONG before any of our emitters ever wear out.

I like lights that press the envelope and get really hot. However, I don't want them to get too hot to touch.

I may represent an unusual sub-species of flashoholic. For me, the disposable-cell-phone-I'll-upgrade-next-year mentality does not transfer to flashlights. I choose intentionally under driven, ultra reliable lights with the intention of keeping and using them indefinitely. That's not to say I won't buy new lights after the next major breakthrough in technology, it just means I'm less focused on raw output. Your mileage may vary. Again, I'm probably the odd one out.

Good info above. Zebralights have great thermal regulation circuitry which dims the light if it gets too hot. On the latest 18650 Zebralights, the user can slightly tweak the thermal regulation setting (approximately 5 degrees Celsius up or down from the factory default). It is a pain to do it, and it isn't much of a customization, but it is something. I'd set it at a lower temp. if you'd like to preserve your batteries and LED (slightly), and set it higher if you'd like slightly more brightness for slightly longer. (Batteries are funny: they have the longest life when kept cool, but squirt out the most current when hot....until they have an "uncontrolled runaway thermal event.") Lights like the Emisar D4 have fantastic thermal regulation customization: you can set it at almost any temp., depending on your usage. Lights with drivers like the VNX2 have user-changeable timed step-down from turbo, which is also a very nice feature. Low-end "hot rods" like the Astrolux S41 have factory-set timed step downs, which usually irritate me to the point of either not purchasing, or immediately modding.

Another non-fan of factory-set timer step-down. If a person is in a cold environment, the emitter will be initially cooler and heat release may be more effective, than in a tropical environment. Also, conduction from a cold hand, holding a thermally well designed flashlight will be more effective at removing heat. This of course applies to high performance lights that will heat up when on high modes.

Additionally, a lower thermal step-down will provide longer runtime because the emitter is not getting as much 'juice' when it gets hot. But how much we are talking about here in terms of someone noticing it is probably nothing. Please anyone correct any errors in this post.

Oveready also has a user option for high temperature step-down.

Modernflame said:

I may represent an unusual sub-species of flashoholic. For me, the disposable-cell-phone-I'll-upgrade-next-year mentality does not transfer to flashlights. I choose intentionally under driven, ultra reliable lights with the intention of keeping and using them indefinitely. That's not to say I won't buy new lights after the next major breakthrough in technology, it just means I'm less focused on raw output. Your mileage may vary. Again, I'm probably the odd one out.

Click to expand...

But if you're buying a light that considered underdriven this year, then by next year the standards will rise and your light is doubly obsolete

Ozythemandias said:

But if you're buying a light that considered underdriven this year, then by next year the standards will rise and your light is doubly obsolete

Click to expand...

I think the HDS is an example of what I mean. High end, robust, manages heat well, and yet is profoundly unconcerned with the lumens race. I'm confident you'll still dig your HDS lights next year, come what may. Eventually, the incremental increases in LED efficiency will add up to something exciting, like a 1000lm flashlight with extended run times and a cool running temperature.