Sofirn SP36 BLF Flashlight Review

The BLF edition of the Sofirn SP36 flashlight offers a powerbank feature from the three 18650 cells, as well as Andúril 2! Read on for more!

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Official Specs and Features

Here’s a link to the Sofirn SP36 BLF flashlight product page.

Versions

Three emitter options are available – 5000K, 4000K, and 2700K.  The SP36 BLF is available as a package (with cells) or without.  That this one is named “SP36 BLF” should tell you there’s a non-BLF version, too. There may be others and Sofirn certainly has other similar lights.

Price

Without cells, the price is $45.99.  With three 18650 cells (as seen here), the price goes up to $53.99.  That’s a very reasonable jump for three 18650 cells!

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Short Review

I really like the SP36 BLF more than I expected to. That’s due in large part to the beam profile – this is a surprisingly tight, throwy light! If you love Andúril you’ll probably love this one too, since it has the newest version (that is, Andúril 2). USB-C charging and the powerbank features are both great. And overall it’s just a solid light!

Long Review

The Big Table

Sofirn SP36 BLF Flashlight
Emitter:	Samsung LH351d (5000K, 90CRI)
Price in USD at publication time:	$51.99
Cell:	3×18650
Turbo Runtime Graph	High Runtime Graph
LVP?	Switch warning
Switch Type:	E-Switch
Quiescent Current (mA):	0.16 (default switch setting)
On-Board Charging?	Yes
Charge Port Type:	USB-C
Charge Graph
Power off Charge Port
Claimed Lumens (lm)	5200
Measured Lumens (at 30s)	3688 (70.9% of claim)^
Candela per Lumen	12.8
Claimed Throw (m)	–
Candela (Calculated) in cd (at 30s)	1295lux @ 4.938m = 31577cd
Throw (Calculated) (m)	355.4
Claimed CCT	5000
Measured CCT Range (K)	5000-5400 Kelvin
Item provided for review by:	Sofirn
All my Sofirn reviews!

^ Measurement disclaimer:  Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.

What’s Included

• Sofirn SP36 BLF flashlight
• Sofirn 3000mAh 18650 cells (3)
• Spare o-rings (2)
• Charging cable (USB to USB-C)
• Manual

Package and Manual

Build Quality and Disassembly

The Sofirn SP36 BLF flashlight is “practically” like the Sofirn Q8.  The Q8 is bigger of course and uses four 18650 cells while the SP36 uses just three. The Q8 is more floody, too, despite the SP36 being described as “a super flooder in a class of its own…”

Have a look at these threads.  These threads are square-cut, anodized, lubed (maybe excessive lube), and quite long.  All in all, this is a good setup.

Inside the Sofirn SP36 BLF flashlight, you can see the body as the cell holder, and brass rings for contact on the head side.  We’ll talk more about this later.

The tailcap is removable, but there’s no point; it’s a dumb tailcap.  I don’t believe it even carries any current.  So while it’s removable (maybe in case you want to do maintenance on the inside or something), there’s no need to do so.

Size and Comps

Weight: 300g without battery
Size:126.7mm x 50mm (length x head)

(Official dimensions from the SP36 Pro model.)

If the flashlight will headstand, I’ll show it here (usually the third photo).  If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

Here’s the SP36 in comparison to the Millennium Falcon.

Retention and Carry

Nothing’s really included for carry of the SP36 BLF.  There’s no lanyard or pouch or anything else.

Power and Runtime

Button top cells are required for the Sofirn SP36 BLF flashlight.  You also want high drain cells.  These cells are in a parallel configuration, so keeping them married is not as important (as if they were in series) but it’s still a good idea to keep them very similar.  That’s better for the cells and safer for you, so just do it.

The kit includes great cells, which are perfectly suitable for the SP36 BLF.

As stated above, they’re in a parallel configuration.  That means the driver is expecting 4.2V maximum.  Parallel means that the voltage input is the same voltage as one cell (4.2V max) but the capacity adds together from the for cells.  The included cells are 3000mAh, so when full, the “battery” (cell holder) is really a 9,000mAh battery.

You may have read into what I wrote above and already considered this, but one cell will also work just fine in the SP36!  You’ll be driving a single cell quite hard doing this, and maybe I’d recommend avoiding Turbo, but the light will certainly work absolutely fine on lower modes this way.  (Any number of cells will work fine, too!)

Now for a few runtimes.  Performance looks good!

I did test Turbo before thermal calibration.  Performance looks practically the same, so that’s pretty good.

And here’s a test with no cooling at all.

The manual doesn’t seem to cover what the switch does to show the battery voltage. So I’m not going to make any claims here either. It is possible to do a battery check through the user interface, though. (Three clicks from off will perform batt-check!)

Charging

A built-in feature of the SP36 BLF is USB-C charging. There’s a charging port on the head on the opposite side from the e-switch.

That press-in cover is very nice and seems quite secure.

Sofirn includes the cable you’ll need – USB to USB-C.  And you need that “USB” side of things – as far as I can tell, C to C charging does not work.

USB to USB-C charging is still quite quick though, peaking at over 2.6A.

I can safely report what the switch does during charging: blinks blue.  When charging is complete, the switch is steady blue.

Powerbank

Also an impressive feature of the SP36 BLF is that the USB-C port can output power, too! In fact, it can output current quite impressively!

In the sort of “stress test” of the output, it went all the way up to 4.1A output.  But while staying in spec for USB voltage, the output is much more comfortable at around 3.2A.  

There’s still low voltage protection when using the Sofirn SP36 BLF flashlight as a powerbank, too – this test shut off around 3.26V.

Modes and Currents

These “A-G” modes are on the product page, but I’d really basically ignore those.  For a user interface like Andúril, that’s going to be less useful anyway. I think most people would prefer ramping. I don’t but I’m not most people.

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps
G	5000	–	3688	16.2+
H	2450	–	1936	4.88
F	1400	–	1032	2.63
E	650	–	375	1.53
D	230	–	113	0.34
C	100	–	45	0.13
B	35	–	11.3	0.03
A	7	–	0.8	4.7mA
–	–	–	0.2	2.0mA

Pulse Width Modulation

We do see PWM on most of the modes here.  I’d only really consider it visible on the very lowest mode.  In all these series photos below, the order is as follows:  Lowest is the lowest when in ramping mode.  Next are all the stepped modes.  Finally (the right-most) is the output when the switch is double-clicked with the light on.

Here you can see a “baseline” – a chart with almost no light hitting the sensor.

Then there’s the Ultrafire WF-602C flashlight, which has some of the worst PWM I’ve seen. It’s so bad that I used a post about it to explain PWM! Here are multiple timescales (10ms, 5ms, 2ms, 1ms, 0.5ms, 0.2ms) to make comparing this “worst” PWM light to the test light easier. That post also explains why I didn’t test the WF-602C at the usual 50us scale.

User Interface and Operation

There’s a single indicating side e-switch on this Sofirn SP36 BLF flashlight.  It’s a responsive and clicky button.  The indicating aspect is quite nice, and also configurable.

In stock configuration, the switch emitters will be orange (it seems) when the light is off.

The switch is configurable, according to the manual.  You will need to be in Advanced UI to configure the switch!

The light ships with Andúril2!  I love it, I think it’s an improvement over the first iteration(s).  There are some things some users might not love about it, but I think overall it’s much more approachable.  I will note though that the nomenclature might be a bit confusing – the light (all lights with Andúril2) ships in Simple UI.  This is not Muggle Mode.  You may think “well duh” and by now you’ve already seen the blistering runtime on turbo of Simple, so you get it.  But just be aware, don’t hand this light to the uninitiated thinking they won’t set their hand on fire while using Simple UI.  Here is where I’d tell you how to switch to muggle mode.  There is no muggle mode.

Here’s a UI table!  This table is directly from ToyKeeper’s Andúril2 manual, which you can view here:

http://toykeeper.net/torches/fsm/anduril2/anduril-manual.txt

I am putting this in a table here with ToyKeeper’s permission.  Thanks, TK!  This is so much better than me writing it because it’s more reliable, and I completely trust its accuracy (at least, if I can paste accurately).  I’m breaking it up a little differently than ToyKeeper did, though I certainly understand why it was done her way originally.

First, the table for Either User Interface.  These actions work whether you’re in Simple or Advanced UI.

State	Action	Result
Off	1C	On (ramp mode, memorized level)
Off	1H	On (ramp mode, floor level)
Off	2C	On (ramp mode, ceiling level)
Off	3C	Battcheck mode
Off	4C	Lockout mode
Off	13H	Factory reset (on some lights)
Off	15+C	Version check
Ramp	1C	Off
Ramp	1H	Ramp (up, with reversing)
Ramp	2H	Ramp (down)
Ramp	3H	Tint ramping (on some lights)
Ramp	3H	Momentary turbo (on lights without tint ramping)
Ramp	4C	Lockout mode
Lockout	1C/1H	Momentary moon (lowest floor)
Lockout	2C/2H	Momentary moon (highest floor, or manual mem level)
Lockout	4C	On (ramp mode, memorized level)
Lockout	4H	On (ramp mode, floor level)
Lockout	5C	On (ramp mode, ceiling level)
Batt check	1C	Off

A table for only Simple User Interface:

State	Action	Result
Off	2H	On (momentary ceiling level)
Off	10H	Disable Simple UI
Ramp	2C	Go to/from ceiling

A table for only Advanced (aka “Full”) User Interface:

State	Action	Result
Off	2H	On (momentary turbo)
Off	3H	Strobe mode (whichever was used last)
Off	5C	Momentary mode
Off	7C	Aux LEDs: Next pattern
Off	7H	Aux LEDs: Next color
Off	10C	Enable Simple UI
Off	10H	Simple UI ramp config menu (1: floor, 2: ceiling, [3: steps])
Ramp	2C	Go to/from ceiling (or turbo if at ceil already)
Ramp	3C	Change ramp style (smooth / stepped)
Ramp	5C	Momentary mode
Ramp	5H	Sunset timer on, and add 5 minutes
Ramp	7H	Ramp config menu (1: floor, 2: ceiling, [3: steps])
Ramp	10C	Turn on manual memory and save current brightness
Ramp	10H	Manual memory config menu (1: off, 2: set timeout)
Lockout	7C	Aux LEDs: Next pattern
Lockout	7H	Aux LEDs: Next color
Lockout	10H	Auto-lock config menu (1: set timeout)
Strobe (any)	1C	Off
Strobe (any)	2C	Next strobe mode
Strobe (any)	3H	Tint ramping (on some lights)
Strobe (any)	5C	Momentary mode (using current strobe)
Candle	1H/2H	Brighter / dimmer
Candle	5H	Sunset timer on, add 5 minutes
Party strobe	1H/2H	Faster / slower
Tactical strobe	1H/2H	Faster / slower
Biking	1H/2H	Brighter / dimmer
Lightning	1H	Interrupt current flash or start new one
Batt check	2C	Next blinky mode (Temp check, Beacon, SOS)
Batt check	7H	Voltage config menu
Temp check	1C	Off
Temp check	2C	Next blinky mode (Beacon, SOS, Batt check)
Temp check	7H	Thermal config menu
Beacon	1C	Off
Beacon	1H	Configure beacon timing
Beacon	2C	Next blinky mode (SOS, Batt check, Temp check)
SOS	1C	Off
SOS	2C	Next blinky mode (Batt check, Temp check, Beacon)
Momentary	Any	On (until button is released)
Momentary	Disconnect power	Exit Momentary mode
Config menus	Hold	Skip current item with no changes
Config menus	Release	Configure current item
Number entry	Click	Add 1 to value for current item

To be completely honest, I’m not entirely sure yet what’s the best way to tell if you’re in Simple UI or Advanced UI.  Based on what I see here and with the light in hand, I think the fewest-clicks way will be 3 clicks from on (technically “Ramp” in the table, but I think “On” is accurate.)  This action – 3C from Ramp – in Advanced UI will iterate smooth or stepped.  In Simple UI, this action will do nothing.  There are other ways, though.  For example, double-clicking from the top of the ramp will either do nothing or go to Turbo.  If it does nothing, then you’re in Simple.  If it goes to 11, then you’re in Advanced.

Another great way to tell, thanks to a reader is to see what the lowest level of ramping is.  Advanced UI has a quite low low.  Simple UI has a much higher “lowest level.”

LED and Beam

Sofirn is using four Samsung LH351d emitters in the SP36. Despite this being a fairly small light (“fairly small” for a 3×18650 light), these reflectors are surprisingly deep. They’re also smooth and give a quite tight beam, in fact.

LED Color Report (CRI and CCT)

All three emitter options are reported as 90CRI, and this 5000K version I have seems to be true to that. Depending on the mode, the CCT will increase a bit. But even on the highest level, the CRI holds up, and the CCT only drifts to around 5400K (which I find to be acceptable.)

Beamshots

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level and the beam hits the ceiling around 9 feet away.

Tint vs BLF-348 (KillzoneFlashlights.com 219b version) (affiliate link)

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.

I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!

Conclusion

What I like

• Complete package with 3 18650 cells is inexpensive.
• Uses Andúril 2, a very versatile user interface
• Very tight beam profile
• Not just a tight beam profile but the cd/lm is quite high – very throwy!

What I don’t like

• Switch indicator features are not well described

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Notes

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