That is very interesting. I wonder if you were able to get a different batch without the timed step down.
Barry, Did Sofirn make a revision on the driver?
I did a quick test last weekend:
- battery: LG INR21700 M50 5000mAh
- depth 37m max
- 100minutes divetime
Flashlight attached to my dpv.
Everything looks ok… 
When free diving you are back on surface long before timer kicks in
I think this is a nice light for recreational diving, i.e., when you fly somewhere warm couple of times a year for few days of diving.
- is very small, easy to fit in luggage
- medium is good enough for night dive, high is nice for lighting dark holes during a day (you don’t need it constantly on then so timer should not be an issue)
- orange peel reflector is ok, you don’t see anything beyond 30-50m even in very clear water anyway, for signaling you not supposed to be farther than 10-20m from your buddy/group on such dives
- it WILL corrode, so is not good for daily diving, this is a problem with all lights that have a current path thru the metal body, salt water acts as electrolyte and metal will corrode and this is happening while you use your light underwater so no amount of rinsing after will help, this will only get worse as light gets banged up and anodizing comes off in some spots. SD01 has battery holder and I think current does not go thru the body.
Hi, can i use my Nitecore NL2150 on that Sofirn SD05
Sofirn made a version without 3min timer, 5000K and 6000K available
https://sofirnlight.com/sd05-diving-flashlight-5000k-new-version-without-3-min-stepdown-p0116.html
https://sofirnlight.com/sd05-diving-flashlight-3000lm-p0016.html
With my plastic caliper, I measure the inner diameter as 21.6mm. I don't have that battery but you may be able to measure it yourself.
That is great to know! Thank you.
Hi! I recently bought a Sofirn SD05 flashlight for diving
1. I would like to know if these batteries are compatible with the SD05 flashlight and if they have plenty of capacity for light.
#1. Samsung 40T (4000mAh / 30A) >> 11.4Wh@10A / 10.0Wh@20A / 8.1Wh@30A
#1. Sony VTC6A (4000mAh / 30A) >> 11.0Wh@10A / 9.8Wh@20A / 8.3Wh@30A
#2. Samsung 30T(3000mAh / 35A) >> 10.0Wh@10A / 8.9Wh@20A / 7.4Wh@30A
2. Is a minimum of 40A or 48A required like Sofirn batteries? Is having fewer amps better for lower temperature?
# Sofirn 21700 4000mAh / 40A 3,7 V 10C
# Sofirn 21700 4800mAh / 48A 3,7 V 10C
3. What are the (Wh) consumptions of H/M/L modes in Sofirn SD05?
Thanks
@ turandot, 4000mAh batteries and above are what you want but compare the specified battery diameters of those in my review with the ones you're interested in. The Samsung 50E will fit fine.
The SD-05 can use ANY 21700, but for my personal preference I’ll take the 50G or another good HIGHER capacity battery (Vs. higher current batteries as turandot lists above).
The SD-05 is quite a good light above water too. I have been using one the last few months by the back door. It really throws better than I thought it would too. And the 21700 is a real plus. I like both the new IF25a and this “dive” light the most lately and the SD-05 doesn’t heat up as fast as the IF25a, but gets VERY close in beam-width and throw with one emitter (Vs the four in the IF25a).
I AM a real fan of this light and as a diver I am looking forward to “taking her down” this winter in Cozumel IF covid doesn’t *@$! that trip up like it did last month (when I got my SD-05 for THAT dive we canceled). 
The Sofirn brand has confirmed to me that I can use any 21700 batteries in the max length 71mm, max diameter 21.9mm
Ok, thanks!
What’s the difference between 48A max current output (Sofirn 21700 4800mAh / 48A) and 10A (Samsung INR21700-50E 5000mAh - 10A) max current output for flashlight operation (brightness, temperature,……)?
turandot, Welcome to BLF!!!
The A refers to the current (amperage) that the battery is rated to produce. In my example SD05, it doesn't pull more than 7.1 amps.
Perfect! Thank you very much.
Great review, Nachtfeuerzeug! 
Thank you xevious!
- which is exactly why putting a 40T or other super high current battery in the light is fine and all; but your not getting any more output from the light over the average high capacity 21700 (which run around 10 amps continuous… covering the light’s max draw by almost 3 amps).
So why not add capacity? I ALSO can confirm using my Molicel P42a in my IF25a from Sofirn that it gets hot VERY fast compared to the 50G (which does get as hot, but not as quickly). 
I’m sure there is a “smidgen” more output on the Molicel, but I really can’t see the difference when I light up the back pasture with both the IF25a and SD-05 using the 50G (actually a wrapped 50G called an “Epoch 5k” from 18650batterystore- great company I’ve been buying from this year- ALL authentic and everything disclosed re. their own wraps).
Sorry if I missed it, but are these using 3V or 6V variants of the 50.2? Has anyone pulled the driver?
EDIT: Found this post here
Seems to be 6V… at least that sample was.
The newer version use the 3 volt 50.2.