Re: Share your opinion with us!
High temperatures will!!! damage the led. Flashlights are somewhat limited in their ability to dissipate heat.
True, but that ability to dissipate heat depends on the environment. If tail standing (free air), it's limited. If hand held, hand serves as extra heatsink and more heat can be shed.
You could test a variety of usage conditions, and see what is "low end" and "high end" in terms of how many watts can be shed. If you design for a worst case situation, that means you leave potentially higher output on the table (FWIW: I'd consider that a pretty good design choice!). If you 'think positive' and design for good cooling conditions, light will be hotter than desired (or even safe) when those conditions are sub-optimal.
For that reason, temperature control sounds nice. Safely power up when possible, limit to safe levels when cooling conditions are poor. But I don't understand why you would cycle this: when lower than what's safe (both averaged, or during a cycle), again you're leaving output capacity on the table. Which was the whole point of a temperature check, right?
So if there's temperature control, I'd simply regulate output such that the light creeps towards a temperature that's considered safe. If enough cooling capacity is available, that would go up to the specified max output. If not enough cooling, then it would be limited by whatever cooling capacity is available. Preferably small steps, so you don't
consciously notice the beam adjusting as cooling capacity changes.
It's like computer cooling, there's 3 basic strategies: (with perhaps some mixing possible)
1) Pick a max temperature, and adjust CPU clock speeds etc, such that power levels matches cooling.
2) Pick an (arbitrary) max power level, constant fan speeds etc, and live with temps going up or down as load varies. Obviously max temp will be reached when ambient temperature is high and PC is doing much work. Pick those max power levels & fan speeds such that things don't get out of hand under maximum load conditions. This is my personal preference for PC cooling.
3) Pick a max temperature, and adjust cooling to maintain that as CPU load varies. This means fans constantly spinning up or down - very annoying.
Unless you include a fan in the flashlight, :devil: option 3) isn't available. Personally I don't think I'd be interested in a light with temperature sensor - I prefer to dial down max output level to something that I
know is safe. Also a temperature sensor adds complexity, cost and idle current drain (however little). That said: the tech (and regulation strategies) is interesting.