Sofirn SP40 Headlamp

Nice tear down Tom!

Thanks for the tear down!

Are you getting your driver boards done at OSHPark?

Thanx! Yep, usually at OSHPark. I got 20 mm's in in the "After Dark" finish - they look amazin!

Just fyi, I posted a mod of another right angle light, the Amutorch AL1, here in the mod thread:

What a driver :smiley: Now i see why it have no cooling ribs . Its possible, but unreasonable to modd this thing. Sofirn engineers have to be fired at once :smiley:

@Tom E Thanks for taking such detailed photos of each step of disassembly! This is a great reference.

Here's pics of the mod - 351D 2700K 95+ CRI reflowed onto stock MCPCB, 20 mm FET+1 DEL driver:

Transferred the brass ring from old driver to new. Thinking I may need the elevated contact surface with the battery tube:

From below, where the driver will go. Cleaned off all the glue, though it was tough goin. It left some scratches where the driver will sit on the edge:

From the top, sanded down the shelf to prep for the MCPCB. The circular patterns really aren't there, well, you can't feel them anyway:

Stock spring transferred, bypass added:

SIR800DP should be fine in this one. Tombstoned a 4.7K resistor for the AUX LED pinout:

All nice and clean, using Arctic MX-4:

Wired up. Long wires needed to reach the switch PCB:

Driver inserted (after flashing Anduril2), showing a shorty tube a friend sent me, total of 3 actually. Good for the SP40, SC31 Pro, and SC31B:

All soldered up, assembled. I do really like the Stickvise that someone on BLF recommended:

Has anyone had issues with the charging port on the SP40? Mine got really hot, started to smoke and now the light only has one mode. Off, on. And the red light on top flashes all the time. I’m not sure if its the fault of the headlamp or of the power supply feeding the USB.

Hi Tom E

Can you share the .hex with Anduril 2 for the SP40.
I got a Oshpark Del driver coming soon. Will do same mod as you did :slight_smile:

Sure. I'll rebuild new just in case of any updates. Can't recall off hand if updated after this mod.

Remind if I forget - got a list now of things to-do this eve...

Here's the link to the Anduril2 for the modded SP40, with a FET+1 driver: google drive SP40

Let me know if it works, should be shared. It contains the .HEX file, as well as a ZIP file of the full source, configuration, and build files used. I use Atmel Studio 7 under Win 10.

The cfg file is as follows:

// Sofirn SP40 (rt. angle head) config options for Anduril 2
#define MODEL_NUMBER "0352" // Unique for this light, in MODELS listing
#include "hwdef-BLF_Q8.h" // same hardware as the Q8 (FET+1 with switch AUX LED)

// the button lights up
// the button is visible while main LEDs are on
// enable blinking indicator LED while off
#define STANDBY_TICK_SPEED 3 // every 0.128 s
// off mode: high (2)
// lockout: blinking (3)
#define INDICATOR_LED_DEFAULT_MODE ((3<<2) + 2)

// TE 2020-11-15: Use the Emisar D1 as a reference for the ramp settings and thermal settings

// ../../bin/ 1 65 7135 1 0.8 150
// ... mixed with this:
// ../../bin/ 2 150 7135 4 0.33 150 FET 1 10 1500
#define RAMP_LENGTH 150
#define PWM1_LEVELS 1,1,2,2,3,3,4,4,5,6,7,8,9,10,12,13,14,15,17,19,20,22,24,26,29,31,34,36,39,42,45,48,51,55,59,62,66,70,75,79,84,89,93,99,104,110,115,121,127,134,140,147,154,161,168,176,184,192,200,209,217,226,236,245,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,0
#define PWM2_LEVELS 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,3,4,5,7,8,9,11,12,14,15,17,19,20,22,24,25,27,29,31,33,35,37,39,41,43,45,48,50,52,55,57,59,62,64,67,70,72,75,78,81,84,87,90,93,96,99,102,105,109,112,115,119,122,126,129,133,137,141,144,148,152,156,160,165,169,173,177,182,186,191,195,200,205,209,214,219,224,229,234,239,244,250,255
#define MAX_1x7135 65

#define RAMP_SMOOTH_CEIL 120
// 10, 28, 46, [65], 83, 101, 120

// safe limit ~50% power
#define SIMPLE_UI_CEIL 120

// stop panicking at ~75% power or ~1000 lm (use D1: D1 has a decent power-to-thermal-mass ratio)
#define THERM_FASTER_LEVEL (RAMP_SIZE*9/10) // throttle back faster when high

// TE - changes:
#define DEFAULT_THERM_CEIL 55 // from 45 -> 65
#define MAX_THERM_CEIL 80 // from 70 -> 80

#define USE_2C_MAX_TURBO

// Make standard mode default, not Simple mode

Thanks man. Highly appreciated.
Will give this a go when i come home in January.
With Anduril 2, a short battery and a Lh351 dogfarts. This will be pretty much perfect for trail running

Anyone in comms with Sofirn in regards to updating (moonlight, Type C port, etc.) this headlamp?

I find that using the 18350, the body is too short for the headstrap. How do you use 18350 with headstrap?

No problem for me….

Seems that you need to use the rubber strap on tailcap. I guess there’s no other way then.

I don’t own one, but it looks like maybe you can turn the battery tube around and it may work better. Assuming that the threads are the same on either end.

Has anyone else fried a 18350 battery using the micro USB charging when the short tube is on? Once the magic smoke was released I tossed the battery and put the 18650 tube and battery back on and it works perfectly. I don’t have the courage to get another short battery and see if it repeats it. Could have been the battery.

The charger might be exceeding the maximum recommended charging current for the 18350 cell.

I tried charging a Keeppower IMR18350 in an SC31 Pro and it was using around 1.17A. The max charging current for this cell is 1.1A.

Crap….I’m sitting here reflecting and I just realized what I did. I’m such a dumbass……I had gotten a deal on Surefire CR123 Lithium’s cheap so I bought some and stored them in the same drawer (metal tool chest in the basement) right next to my rechargeable Lithium’s. They’re all in plastic cases and appear identical. BUT THESE ARE NOT RECHARGEABLE!!! Surefire makes rechargeable in this size, but these ain’t it.


Holy F, I’m glad I didn’t stuff them into USB rechargeable lights and gift them to folks for Christmas. My mouth is open at my own stupidity.

Did you avoid breathing in the fumes and letting it get in contact with your skin?

There have been some horror stories about cells exploding, followed by being poisoned and then long term impact to health.