No idea, I never run my LEDs in DD.
You’ll never get peak performance with DD, it either runs at too much current or not enough current.
Ideally the LED operates at the peak of the curve, which is basically impossible to do with DD because battery voltage drops so quickly.
And if you run it where the battery voltage is fairly stable, ~3.7v, then the initial spike of 4.2v just makes the LED heat up excessively and decreases performance, assuming you don’t instantly kill the LED.
Ok then if I read things right it performs worse with higher current butt it also depends on how long it’s run at that current. Or no? For shorter burst throw activity do ya really need to use lower current batts? And if not can this be mitigated with anything else to improve thermal paths when reflowing?
To me at least dealing with this lower current batt jazz and this led is a PITA. It’s just another frickin’ thing I’d have to keep track of besides all the other shizen I gotta keep track of with ala in just safely charging batts itself. :laughing:
Oh and if it performs worse with high current batts butt STILL outperforms an abused XPG2 then one is still ahead, right? According to Luminarium it’s not gonna harm the KW hardly at all. So what if I get a bit less performance. Butt that’s just for me. Others want it all all the time, baby.
PS. If I understand Luminarium correctly it can go 20 minutes in Super Thrower mode. Does he mean with lower current batts, apparently so. Butt OTOH can it Super Throw for 5 mins with a 30Q, that I’m not sure of. Hell I rarely go longer than 2 mins on Super Throw mode with anything I own. I got neighbors ya know. :laughing:
What if the led can survive whatever amount of overcurrent? When you do that you're pumping more power into the led it can fruitfully handle.
Wrong. The only reason a regulated linear setup generates more heat than plain direct drive is the price of regulation. The LD25 driver, for example, uses an AON7520 MOSFET and achieves regulation by sensing current through a 10mΩ resistor and using this feedback to precisely tune the VGS MOSFET gate voltage for it to let go no more than the preset driving current, thus no :THUMBS-UP: PWM. The net dissipated power difference versus the same driver without regulation is the additional power spent in the sensing current path, Psense = I² × Rsense. At 5A that is 0.25W, this new LD-25 is particularly efficient in this regard. And of course bear in mind the regulator has to take and bear with any additional voltage delta times current power, thus the increased heat in the driver. This increased heat in the driver nets reduced heat everywhere else in the current path: springs, switch, cell, emitter, etc.
A MOSFET misdriver is just a PWM micro-controlled switch. As I said above, you pay a regulation price in linears. However, this price is not always a hurdle. You complain about heat generation, but do you understand where and how is the heat generated? Any time you “adjust” a plain MOSFET setup via unbypassed springs, using higher internal resistance cells, etc. what you're doing is redistributing where the heat is generated. Which of course can be good.
A linear driver has to burn all excess power to avoid it reaching the emitter, which of course will make them hotter than unregulated misdrivers which of course do nothing.
Sure as FLICK a misdriver isn't going to be very hot, how could it be? It is doingnothing besides quickly switching on and off when required. However, this does not mean the heat isn't going to be generated elsewhere. It's the emitter who is going to take the penalty among other parts like the switch, my dear. Pumping 7A in the white flat isn't going to insta-kill it, but it sure increases emitter stress unnecessarily and nets you lower performance.
“Sure as FLICK a misdriver isn’t going to be very hot, how could it be? It is doing nothing besides quickly switching on and off when required. However, this does not mean the heat isn’t going to be generated elsewhere, you know? It’s the emitter who is going to take the penalty among other parts like the switch, my dear. Pumping 7A in the white flat isn’t going to insta-kill it, but it sure increases emitter stress unnecessarily and nets you lower performance.”
Man, I almost can’t wait to read Luminarium’s reply to this one.
Sure as FLICK I can wait. In fact I don't really care. No one's paying me for this and I believe it is unlikely he's going to get off his high donkey. He may already be aware of the provided information, except he may not have tried a proper linear driver like the ones from led4power or an LD-25. Or he just doesn't care.