S21A thermal protection

A friend, bought a S21A (4 modes) and it seems like it does not have thermal protection (or the protection is not working)
After few minutes on the brightest settings the light getting too hot for holding but not stepping down.
Can you recommend an alternative driver with thermal protection or even better, a FW for burning on the original driver
THX


Have you tested the output on turbo with a lux meter?(some apps can do it). I’m asking this because the thermal throttling is very subtle, and you may not see it. Also, even with thermal protection the light can become hot for some people.


I didn't test it with lux meter but it is getting hotter and hotter to dangerous temps

This is a runtime graph of my S21A (purchased two years ago). The four-mode version. It should throttle down to about 42% brightness in about three minutes.

If you read my S21A review (link in my signature), I also wrote:

Note this light now comes with a 12 mode group, with some of the modes having 50% as the top brightness level.

Yes it is getting REALLY hot, I want to change driver or FW in order to decrease temperature after about 1 min

How much is REALLY hot? (Celsius degrees). If thermal protection is not working properly you may have a defective driver. If he bought the light from Simon, he may be able to send a new driver if you prove objectively that thermal protection is not working. Or you can just select the third mode (30%) to prevent overheating.
I think that doesn’t worth buy a new driver. If it is working properly and he wants a cooler light, I would choose one with anduril to control the temperature or with one buck driver that is more efficient and generates less heat. I have a s2+ with 5A driver and I can’t hold the head after some time on turbo and some people can’t even hold the body.

It’s funny, most enthusiasts pay extra for a light w/o ATR.

You could replace the driver with the other driver that comes with the S21A: 20mm Driver for SST40 ,12groups , max current output 6000mA, Temperature protection management inside

And set it to mode group 8 which is 4 modes and highest at 50%. I’ve done that with some of my flashlights to limit the current. Certainly less output, and will eventually heat up, but still plenty bright at around 3 amps.


But he is not enthusiasts :)


Thanks, Seems like a good option.

I don’t think he will get a lower temperature. The temperature threshold will remain the same, it will just take longer to be achieved. Unless the sustained power is over 50, then he’ll get a lower temperature. But usually the flashlight throttles down to around 30, and, once it does that, doesn’t make any difference be in 100% or 50% mode.

These Convoy drivers are supposed to max out at 55 degrees Celsius, which is not that hot. So it seems there is something wrong with the driver if the S21A is getting too hot to hold.

Mine will get very warm, but never too hot to hold. And I have 8 of these drivers.

I just measured one in 100% mode and it maxed out at 58 degrees Celsius, but then settled down to around 43 degrees after several minutes.

I then measured it at 50% mode and it maxed out at 52 degrees after several minutes, and then settled down to 43 degrees once again.

My S21A came with 12 group mode… (red PCB driver with V20 text on the batt side. yes it get hot really quick but i measure it goes to around 50C max and i know the thermal protection works becouse its goes down to about 48 and stays there

If you can get access to an infrared temp meter, you should get close to this.