[Review] Sofirn SP33S || Cree XHP70.2 , 1 x 26650 / 1 x 21700 || Great Power and Thermal Regulation Observed

The flashlight was sent to me by Sofirn for review.
Here's the product's details: Sofirn SP33S



The flashlight comes in a regular cardboard box.



The following contents are included in the package:
- Sofirn 26650 battery w/ 5000mAh of capacity.
- USB-C charging cable.
- Lanyard.
- 2 x replacement o-rings.
- User manual.



The SP33S comes in matte black anodisation and has a subtle design.



It's opertaed via an e-switch that's mounted in the lower part of the head.
The e-switch is slightly protruding and provides a tactile feedback.



An LED is embedded into the switch and is used to indicate the battery's level during normal operation or charging.
It's also worth noting that the switch can be programmed to stay on while the flashlight is turned off.



The charging port is mounted opposite to the switch.
A rubber flap is in place to keep moisture and dust out of the charging interface.



The charging takes place using a regular USB-C cable.



A few thick heathsinking grooves are incorporated into the head's design.



The body of the flashlight comes with some nice horizontal grooves that improve the overall grip.



The front part of the head makes use of a metal polished bezel that helps protect the glass lens.



Looking into the head, we can see a light orange-peel reflector along with a nicely centered Cree XHP70.2 emitter.



The driver seems to be press fit and glued in place.
A brass tab is used as the positive terminal.



The tail implements an anti-roll pattern and also includes a hole for attaching the lanyard.



The tail houses a thick copper spring.



Both the front and rear threads are very cleanly cut and arrived anodized, which allows the flashlight get mechanically locked out.



The tail is completely flat which allows the flashlight to tailstand.



User Interface

The following actions are supported by the flashlight's firmware:

Turn on/off: Single press.
Ramp Up/Down (when in ramping mode): Long press while on. Releasing and pressing the switch again will change the ramping direction.
Mode cycle (when in stepped mode): Long press (Low > Mid > High).
Turbo: Double press.
Moonlight: Long press from off.
Strobe: Triple press
Lockout: Quarduple press while off.
Switch from ramping to stepped modes: Quadruple press while on.
Configure Indicator LED: 5 x clicks while off ( ON > Blinking > OFF)
Mode memory is on.
Low Voltage Warning and Low Voltage Protection is present.

Output

Here's my output measurements along with the respective current draw (stepped mode).



As we can see, the Sofirn SP33S is able to push more than 4600 lumen OTF at turn on.
The moonlight is also quite good at 9lm, provided that we're talking about an XHP70.2 flashlight.

Power Regulation

Here's a power regulation graph of the stepped output modes of the Sofirn SP33S.



What we can see in the graph:

  • Turbo's power regulation seems very interesting. It seems to follow some kind of 'stepped' regulation for Turbo.
  • The full output of Turbo is sustained up until the 3.8V level.
  • High is fully regulated up until 3.3v.
  • Medium and Low are fully regulated for the whole span of the battery's voltage.


Thermal Regulation

Here's a Thermal Regulation graph I've created for Turbo and High.
The graph was recorded while using a high drain 21700 cell.


What we can see in the graph:

  • Turbo's full output is sustained for 1 minute and 20 secs. Post the 1:20 mark, the output is regulated to keep the flashlight's thermals in place.
  • High's full output is sustained for 21 minutes. Thermal regulation kicks in after that.
  • Both modes show signs of true thermal regulation - The output will constantly increase/decrease in order keep the flashlight's max temp constant.
  • The thermal regulation uses a ramping pattern to adjust the brightness. No sharp / sudden changes can be observed.

How long did it stay high? Doesn’t look large enough to sustain 1800 lumens very long.

Yes I also want that. Please make output test for high mode with ceilingbounce app. It will be interesting if new SP33S is good competitor of Thrunite TC20. There is nothing in any review of SP33s that to include runtime test. For BLF user that’s the most interesting part I think from any review.

Sure thing!
Tomorrow I will also be performing and uploading the regular thermal regulation test for Turbo, High and Medium modes to see how the thermals of the flashlight perform!

Thanks a lot in advance :+1: . Thrermal and runtime graph will be very useful.

The knurling looks nice and modern. Also nice is XHP70.2 in OPR. If driver and firmware are good, I’ll get one.

bump

This looks cool.

It should be boost driver but behaves like buck? Besides Barry mentioned … Maybe its fake 3V XHP70? :smiley:
12A on turbo? Really?
For reference how should look real boost driver runtime graph.:

No runtime diagrams for the SP33S yet?

Hey guys, sorry for taking an extra day to get my thermal regulation tests going, but I got pretty busy

It seems that the SP33S packs great thermal regulation!

Thermal Regulation

Here's a Thermal Regulation graph I've created for Turbo and High.
The graph was recorded while using a high drain 21700 cell.


What we can see in the graph:

  • Turbo's full output is sustained for 1 minute and 20secs. Post the 1:20 mark, the output is regulated to keep the flashlight's thermals in place.
  • High's full output is sustained for 21 minutes. Thermal regulation kicks in after that.
  • Both modes show signs of true thermal regulation - The output will constantly increase/decrease in order keep the flashlight's max temp constant.
  • The thermal regulation uses a ramping pattern to adjust the brightness. No sharp / sudden changes can be observed.

Well, it looks like the same ATR algorithm from the SP35 and previous SP33 drivers. Kind of a bummer, but understandable for a sub $50 light with a boost driver. The fact it pulls 12 amps explains why Turbo is regulated to only 3.8 volts. You generally see input current around 10 amps max to drive a xhp70.2 to around 4500 Lumens off a 1S boost driver. I tested the TC20 V2 and it’s fantastic. A bit down on output, but a far better regulated driver for like $20 more.

Is this xhp wired for 6v or 12v?

Probably 6v. There’s only a few I know of that are 12v.

That is again a very simplistic temperature regulation algorithm. Pity the light doesn’t run Anduril. Otoh, it saves me money.

Thank you for posting!

All sofirn ATR have the same thermal regulation like this in graph. It is like relay with on/off regulation. When the temperarure go over some point in most cases 55°C they just lower output in same manner to about 40°C on body, after that ot go to high slowly. Same stupid regulation on Wurkkos HD15 and HD20. From zeroair graphs on different Sofirn light you see the same pattern. I hope some day they to implement PID algorithm in firmware.

I ques thermal sensor is fixed on PCB with poor heat dissipation. In process batt is dropping voltage and its more work for driver to keep stable output so it starts to heat up and thermal protection kicks even after 20 min at hi mode.

Noice! I like that the switch can be configged.

I prefer at all to remove that sensor for sustained high output :smiley:

Do you measured maximum surface temperature of SP33S?

Thanks for the review. Sustained brightness in high mode is pretty respectable for a single 26650 light. Seems to be a big improvement from some previous Sofirn flashlights.