Thinkin’ about venting gas and sweet smell…the T1 could actually compete with this nice device:
Just kidding, of course! :smiling_imp: 
Both good points Zulumoose.
Which is why I felt it important to state my test conditions.
The first test has now run to completion. I got a further 55 mins or so on MAX CW and the tube and cell were still not “hot”. I’m topping off a protected Panny 3400 at the moment for another test.
Typically I have been using the lantern attached to a metal surface. I chose to let it hang so the magnetic cap could not use the metal as an additional heatsink.
Your idea of sitting it on an insulating surface might have to be part of my further testing but I’ll wait until I get my IR gun back again after the weekend.
I was just thinking about this earlier. Does the magnetic cap physically touch the metal surface?
If so, Zanflare could ship everybody a “fix it kit” to prevent thermal excess. It would be an 8” piece of square sheet metal. 
Hang the metal “heatsink” in your tent and attach the lantern to it. Makes for a super steady base when not hanging.
I’m just goofing around.
Goofing noted…
Checking using a steel ruler, it appears the tailcap and the plastic base are exactly flush when screwed down tight. You could always back the cap out a little if it wasn’t, as the threads are not anodized. So yes, the magnetic tailcap does physically touch the surface.
Having said that, I suspect that the amount of heat drawn out through a few threads and layer of paint over a circular contact surface only 20mm (3/4”) in diameter would be pretty minimal.
I just wanted to rule that possibility out for my tests.
The “fix it kit” could also be a bigger tailcap with fins, so it would screw directly on the heatsink.
I think we need some numbers here.
We humans feel pain at 55 degrees Celsius, and experience that as alarmingly hot. Electronics can withstand 250 degrees Celsius and more. Li-ion batteries are in between, thermal runaway starts only at over 150 degrees Celsius, but I guess degradations of the battery already starts at lower temperature. But still I reckon that a battery at 80 degrees Celsius (way too hot too touch) would not be unsafe? Anyone with more knowledge about that?
Btw, thanks for the very good hands-on review Den!
Exactly my point in my post in the gb thread.
HKJ frequently ends his tests with temperatures well over 50 Celsius degrees over ambient. Maybe the cell vented because it was somehow faulty?
ADDED:
Mooch frequently exceeds 80 degrees. Sometimes 90.
Quick browse and I found him going to 97:
All the HKJ reviews I’ve read he usually ends the amp draw tests early if they exceed 80°C. For a continous discharge rating it has to stay under that temp.
In those tests the battery chemistry is generating the heat, not it being heated by an external source. Maybe that’s an important distinction?
Based on Mooch’s background, he’d know for sure.
I PMed HKJ, maybe he’ll comment…
A member of the German TLF just checked his Zanflare T1 with the original batteries. He also used an IR thermometer. These are the results:
Discharge start @ 4.12V, maximum brightness in coldwhite:
o IR-temp. on tailcap: 0:00h 25°C, 0:15h 41°C, 0:30h 48°C, 0:45h 51°C, 1:00h 51°C
o IR-temp. after 1:00h on battery inner tube, max. 10s after interruption of operation / removal of battery: 53°C, 3.7V resting voltage
Test means nothing if we do not know the conditions of the test.
Ambient temp?
Airflow?
Orientation of lamp?
Material in contact with tailcap?
Ideally the test should be done without airflow at a known ambient temp in worst case scenario of lamp standing upright on an insulating surface like wood, or even worse on material, such as a tablecloth, blanket etc.
I doubt a cell vents below 90°C internal temperature. The internal temperature will depend on current draw and internal resistance in the battery (And of course ambient temperature). This means that the risk of a venting cell will be high when using a cell with a current draw that makes it hot when the tube also is warmed from the led.
I wonder how much the led heats up the interior of the battery tube at the top, leds can run above 100°C (The temperature of the tube may not tell the full story).
Thanks for the heads-up DBSAR.
After 10 days of daily usage of my three T1s, today, just before I read your post, my daughter bring me her T1 so I can recharge it and for the first time I noticed the very hot tail cap. Hasn’t happened until today even after hours on max so my guess - and its only a guess - maybe not all T1s have that issue?
I will keep my eyes open about this dangerous behavior.
I still say “Sweet Smell Of Death” would be an awesome name for a thrash-metal band.
Just thinking out loud here… and getting strange looks from people around me.
Know the Nitefox UW360 flex-neck light-thingy? It comes with a magnetic-suck base (seriously!) and a ferric disk to act as a wider stabilising base, and to be able to stick it semi-permanently to another surface.
Well, what about something similar, a ferric disk that would stick to the magnetic-cap of the T1, and with a wider base and thus more surface area, wick away heat to the outside world?
Bugger, I just suggested that about a minute ago.
Doesn’t seem like a bad idea. See the UW360, ’though that’s not for heatsinking.
I’d imagine the T1’s cap has to make contact with a bottom surface, else there’d be an air-gap that’d seriously reduce its magnetic-suck action.
My protected cells are too long to fit this lantern.
I have 3 T1s …… I ran all 3 for several hours on high CW and the tailcaps on all remained as cool as the ‘outside’ of my fridge…… Not saying this couldn’t change in the future but if there is a heat problem then it seems it may be a QC problem and would not be occurring in ALL T1s.
Considering the majority of present owners of the T1 are not experiencing the same thing as the op while using the cell that came with the unit but from a known old cell (might’ve already high IR) , shouldn’t it be fair to Zanflare to have this thread’s title edited ?