My Solution for FENIX Turbo Overheating , step right in :)

when i first got the L2D i test ran it to see how long it could last, i let it tailstand and after 13 minutes it overheated and dimmed down


So i know some have seen this as an issue some may not as they either have it on a bike with cool air flow or constantly in hand for more heatsinking BUT if you like to be able to tailstand it on a table in the middle of the room it will overheat after 10 minutes and go dim and kill the batteries....well i went to Home Depot and browsed a few items and found the best i could a copper pipe 3/4 inch it said "diameter" and 1-1/2 inch length ...the length is perfect as it is same exact length size as head but inner diameter was a hair to loose so i had to use aluminum foil to fill the gap which came out very good , now all i have to do is finalize the solution by epoxying the edges front and rear only ,dont wanna gum up entire inner tube head incase i wanna disable later..and of course paint it black

ran it for 1 hour and it got hot but it stayed bright and did not die , i shut it down after an hour which was plenty for me to know it works well enough...also it was done in a room at normal temp around 70 degrees with NO FAN or Air Conditioning to help


i was hoping to find same type pipe but a little more beef in thickness,this is kinda thin but it works

I would put some cooling fins on the pipe and not bond it to the flashlight but just make it a good snug slip on type jacket and leave it like that for when you need it. They make copper foil tape that I have used to make large heat sink fins on things that normally would have nothing and what a different in made to have 1 and half to 2 inch wide tape coming out on 2 sides for 5 inches and nothing else.

copper foil tape , interesting... only thing i can see would be no metal direct contact as adhesive is inbetween but i would like to try some

Its a very thin layer of adhesive and with enough bonding area it appears to work very well. I use it at work pumping 150 watts or so through resistors for load tests that I don't want to get hotter than I can pick up. You can fashion it into a set of fins all around. Make some angled down to hold the thing upright and it will keep it much cooler due to the greatly increased surface area. Just using a thermal grease that you can wash off to the copper pipe section rather than an epoxy so you can take it off any time you want will be good enough.

How exactly is that supposed to help heat dissipation? The surface area is the same, the added layers work more like an insulation.

If you want to tailstand, just put it on high mode and it won't overheat.

Why not just tailstand it in a glass of water?

Is your L2D a Q5? I'm just curious because my L2D Rebel 100 doesn't overheat tailstanding in turbo mode, nor does the P4 version I have.

This helps with dissipation of the unwanted heat in that
1. There is more heatsink to absorb the unwanted heat
2. Thermal conductivity of copper is about 60% greater than aluminum
3. The surface area is not the same but has increased from the larger OD of the copper tubing sleeve.
Not the most visually appealing mod, but it seems to work and if qip is happy, good for him.

My P3DCE Modded with a WG Q5 (by datiLED) does not overheat and dim even when on for 40+ minutes tailstanding.

NutSAK said:

Is your L2D a Q5? I'm just curious because my L2D Rebel 100 doesn't overheat tailstanding in turbo mode, nor does the P4 version I have.

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That's a problem then, because it means the heatsinking is very poor.

Also, L2D has no thermal protection so won't dim down when it overheats.

qip said:

when i first got the L2D i test ran it to see how long it could last, i let it tailstand and after 13 minutes it overheated and dimmed down

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Are you sure it wasn't just a depleted battery?

BBL said:

How exactly is that supposed to help heat dissipation? The surface area is the same, the added layers work more like an insulation.

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+1

mines a Q5...i have had a couple of L2d "p4-Q5" in past and they all on fresh batteries dimmed after 10 minutes so i wanted to give this a try

painted it black , looks good, i have not epoxied it just gonna use as a sleeve for when i need it

Has anyone considered dunking it in a glass of water? They are watertight (atleast, until you go diving with them...)

My $0.02: My L2D has never overheated on turbo when testing runtime, but your idea is an interesting one for those who have overheating problems.

Jarl said:

That's a problem then, because it means the heatsinking is very poor.

Also, L2D has no thermal protection so won't dim down when it overheats.

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No, it doesn't. It means the heatsinking might be poor--but it isn't. The body of the flashlight gets VERY warm while doing this, showing that it does not have "very poor" heatsinking. Neither my Cree nor Rebel versions dim in output in turbo mode, and I can run them until the batteries die.

Nice mod. It looks kinda cool too.

qip said:

mines a Q5...i have had a couple of L2d "p4-Q5" in past and they all on fresh batteries dimmed after 10 minutes so i wanted to give this a try

painted it black , looks good, i have not epoxied it just gonna use as a sleeve for when i need it

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That is really strange because fenix doesn't have any auto dimming feature to prevent overheating. I've done many runtime tests with my l2d Q5 and L2D 100 without any cooling and they don't overheat. Still looks like battery issue to me.

maybe cuz im running e2 lithiums at 1.6-1.7v as to nimh at 1.2-1.4v... extra voltage heat ....3.4 vs 2.8 ?


i should note i never read that rebels had any issues cuz people say they have lower VF , just the crees


maybe we should get a poll going....tailstand light in turbo and see if it lasts more than 30 minutes straight minumum, no air cooling assist just room temp?

NetGod3Com said:

This helps with dissipation of the unwanted heat in that
1. There is more heatsink to absorb the unwanted heat
2. Thermal conductivity of copper is about 60% greater than aluminum
3. The surface area is not the same but has increased from the larger OD of the copper tubing sleeve.
Not the most visually appealing mod, but it seems to work and if qip is happy, good for him.

Click to expand...

BBL said:

How exactly is that supposed to help heat dissipation? The surface area is the same, the added layers work more like an insulation.

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It seems that 1 and 3 are helping. Number 2 doesn't seem likely just given the basic concept of thermal resistances in series.

After an hour the light is probably operating at a steady state temperature and the combination of the increased surface area (exposed to the air), higher mass, and higher specific heat capacity are keeping the operating temperature lower.

TONY M said:

Nice mod. It looks kinda cool too.

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+1 on looking cool! (Just slip a glow in the dark ring between the inner and outer layer!) I don't have the background to know whether this will work to help with heat, but its a great looking mod- especially polished to a mirror finish. If you made this change and now the light works better, Great!