How long can you really run your HO lights before heat becomes an issue?

[ShineOnYouCrazyDiamond]

I have several HO setups which involve a KT4 turbo head and LAs like the HO-M6R, 1185, 1111, IMR-M3T, etc. With cells like the IMR18650 and the IMR26500 I am easily able to get 40 minute straight runtimes on these bright lights but I am not sure if it is safe to run them straight that entire time.

I've run them as a test with a fan blowing directly on the head to cool it and the head feels very cool to the touch, but when I take the head off after 5-10 min the inside reflector is sizzling hot.

I know there is a heat transfer issue because of the impact reducing mounting mechanism of the reflector.

So my question to everyone is what are the heat dissipation limits of the KT4 head for longer term runtimes? Does the head heat up to a thermal threshold and then just hang there or will it keep getting hotter until a of some kind? Will heat transfer back to the cells overheat them?

I usually use AW SoftStarts so I could always run at a lower setting but even at 30% brightness it is still 0.45x the high amp current draw.

I guess the real question is - is it safe to run HOLAs on high for long runs >20-30min straight?

 

[leukos]

I don't think you will ever have a problem with any of those lamps in the M6. Now if you figured a way to fit Osrams in there, you might get some melted shock absorbing rings, but remember the M6 was built for the MN21, a fairly serious heat producer itself. I've been running several of those setups you mentioned above for a few years now with no issues, and I do long runs too. Just use it and have fun! :thumbsup:

 

[ShineOnYouCrazyDiamond]

That's re-assuring. :twothumbs Thx.

 

[ampdude]

You should never run a high output flashlight sitting on a table by itself without proper precautions. I guarantee you if you turn on a C2 or 6P Surefire with fresh OEM batteries and a P61 lamp assembly and set it down on a table, you will not be able to touch it after five minutes. I've done it myself and burned my hand. When you run a high output incan lamp assembly or an LED you should hold the light in your hand. Your hand will act like a big heatsink. The light may get uncomfortably warm, but you should never reach the danger point. This is especially important in the Summertime or in warmer environments. Grip the flashlight tightly for best results. However one thing I should point out.. the IMR chemistry is safe. The worst that should happen is a battery failure or loss of runtime. The batteries you have to worry about explosions with are lithium primaries or lithium cobalt rechargeables.

 

[ShineOnYouCrazyDiamond]

You should never run a high output flashlight sitting on a table by itself without proper precautions.

No worries on that front - I am very experienced with Lithium chemistry from my RC hobbies. Watching a 6s1p 5000 mAh LiPo pack go up in flames is quite the experience.

In light of what leukos said I performed what I would consider some 'brutal' runtime tests on HOLA packs.

I used my IR temp meter to take reading during the runs to make sure all Li cells stayed under 140*F. I kept all conditions the same for each run. No extra cooling on granite countertop and room temp around 68F. Tests run in 20 minute intervals to come up with total runtimes and for cooling and bettery temp tests.

Setup 1:
Mega w/ KT4 head, WA1185, both IMR18650 and LiCo 18650 cells tested. Head temp: 107*, body temp: 99*, reflector temp 180*, battery temp after run 104* at hottest point. Total runtime was ~28 min for IMR cells and ~46 min for 2.6 AW LiCo cells.

Setup 2.
2x26500 Mega w/ KT4 head, WA1111, IMR26500. Head temp 105*, body temp was low 90s*, battery temp was low 90s. Runtime ~38 minutes.

Setup 3.
Stock M6, HO-M6R, 6xIMR16340. Total runtime ~30 min. No temps taken but never more than warm to hand.

 

[leukos]

Thanks for doing some temperature tests to verfy the safety of these setups. From what I understand, LiCo's have peak performance when their internal temps are around 110*. I have five battery carriers for my M6 and I can just keep pumping them in there without any heat related issues with the 1111. The 1185 gets a bit warmer, as your results show, but nothing I would ever worry about. :thumbsup: