I’m finding myself in a quandary…
KaiDomain now has the 3V XHP50.2 in higher light temps and since I’m not liking the inherent inefficiency of most boost drivers.
Looked at the 20mm SST40 Driver over at Convoy, but it is super aggressive on thermal throttling, as seen in a review of the S21A with the SST40 on Youtube.
With the H1A driver and XHP50.2 6V in the S21A, I can have it on full power for almost 3 minutes (Maybe more) till the light gets extremely hot for me.
So, I’m looking around trying to find some form of PWM driver that can do 6A at 3V that is readily available, or build if I have to.
To be honest, it’s not the inefficiency of boost drivers that’s making the light hot.
It’s just that the H1A doesn’t have any kind of thermal throttling, and unlike most linear and all FET drivers, boost/buck drivers keep their output constant over the whole runtime, meaning brightness doesn’t go down, and the light can get hot all day long.
TLDR: Unless you are ok with losing brightness, you can’t escape physics.
Yeap, I know that much that the H1A has no thermals, I was kinda hoping to find a PWM that also has no thermals as a part of their design that can push as much current as Simon’s SST40 Driver without it immediately going into said thermals. Also thought that even PWMs act the same way as Boosters when it comes to supplying what they are told to unless a controller says otherwise.
Not gonna happen.
3A*6V=18W
6A*3V=18W
You need a light with better thermal design than the S21A.
I'm using another Convoy driver I found. It's the older version of the new one that's selling on AE but is 17mm or 22mm only.
US $5.78 | 17mm / 22mm driver for luminus sst40 LED https://s.click.aliexpress.com/e/FWWg4WYu
It doesn't have thermal throttling. The UI is nice too. It ran my sst40 and runs my 3v xhp50.2 just fine. You do need a reverse clicky with it though. Otherwise there are nice nice boost drivers out there.
What does power output have to with this?
Anyway, I meant External Thermal control, like a Thermistor/NTC or Probe, not built in protection that some regulators have, which are effectively an internal switch, not a throttle via a control program.
Now I wonder if I can just bypass the throttle in Simon’s driver with a 10K resistor instead of the Thermistor
Cant you just use a decent linear driver if you are going with the 3v xhp?
Not quite what you’re asking for but Led4Power does a 20mm linear driver which won’t throttle:
https://led4power.com/product/ld-a4-20-2-12amp-20mm-constant-current-led-flashlight-driver/
You can get a 6A version which is adjustable through menus from 4-6A, or you can get up to 12A version, or you can choose to run them DD (selectable via a menu) to kill your electronics even faster! 
These also have the capacity for thermal regulation via an external NTC should that interest you. Or, if you want to get really funky, you can have the FET on the LED board along with the NTC so you know the thermal control is reacting directly to the LED board temperature.
Edit: And i think what BlueSwordM is explaining is that changing the driver won’t change how quickly the light heats up, you’ll change the electronics to find you can still only hold the light on full for as long as you can hold it now.
That is exactly what I am looking for, except there does not seem to be any decent ones readily available. 
With how durable modern, automotive grade electronics are ,with a rating of 125C I think, the actual speed of the light heating up does not concern me at all, it is the aggressiveness of any built in thermal throttling that does.
May have to look into LED4Power again some time with that offboard FET, but they don’t have MCPCBs complete with the LED and all that.
Ah OK.
Sorry then.
led4power’s driver would be your best bet then.
No big man. Just a misunderstanding somewhere on both our parts me thinks
Led4Power drivers are extremely high quality, as good as anything out there. Matt Smith on this forum also makes a killer driver sold through his company Adventure Sport Flashlights (Google it) that can do 3v and 6v with the zener diode mod. Its essentially a direct drive board with killer modes to regulate the output from firefly to direct drive. It will easily do 13A with a good battery, robust switch and bypassed springs. I’ll be getting one soon.
Richard at Mountain Electronics also does very high quality drivers and has linear drivers and fet drivers as well as boost drivers.
If you really want an easy way to get around thermal throttling and have high output, get a driver with a UI that allows a step down when the max temperature you can stand is reached.
Yeap! I’m familiar with Matt! In fact, my stumbling onto his YouTube channel started my tumble down this rabbit hole 
Also familiar with MTNElectronics… though he seems to have a BIT of a supply problem, ever time I try to select a driver, always out of stock.
Back to ASF, even know of the driver he made and premiered at the debut of the 3V XHP50.2, only thing that kept me away is that it is a 17mm driver, not a 20mm 
With the results that he got with said driver, I may have to look into the pill adapters that Simon makes for the S21A and others, but hey, if I want to have something more on the simple side, yet relatively compact and still powerful as hell…
Yep! I tried to get an led from there and it was out of stock, so off to China and got it from Convoy. You won’t find components cheaper anywhere else.