EDIT 2016/3/6: verified the pwm frequency, which is 17.2 kHz on all modes except moonlight (8.6 kHz) and turbo (no pwm).

Astrolux S41 is a quad emitter hotrod light manufactured by Manker. It is equipped with either high CRI Nichia 219b or cool white Cree XP-G2 LEDs. My light is the Nichia variant purchased from banggood.com. The light is also available as a Manker E14.

Manufacturer specifications

Battery type: 1× 18350, 16340 or 18650 with an optional tube

LED : 4x Nichia 219B 5000 K (also available with 4x CREE XP-G2 6500 K)

: 4x Nichia 219B 5000 K (also available with 4x XP-G2 6500 K) Body material: Aluminum/Copper

Switch type: Reverse tailcap clicky

Waterproof: Yes, IPX8

Lens: TIR

Protection: Low voltage warning (2.9-3.1 V), reverse polarity

Modes: Selectable 4 or 7

Special modes: 10 Hz strobe, battery check, biking flasher

Mode memory: Selectable

Length: 80 mm

Width: 24 mm

Weight: 90 g

The S41 driver is the same as in the popular BLF A6/Astrolux S1.



Astrolux S41 with a 18650 and a 18350 battery.



The light accepts protected and unprotected cells. In addition to 18350s 18650s can be used with an option 18650 tube. There’s a double spring in the tailcap.

Measurements

Please note: lumen measurements are only rough estimates

My diy 30 cm integrating styrofoam sphere has been calibrated using a Fenix E05 on high with manufacturer’s claim of 85 lumens. Verified with an Olight S10 that has been measured with a Labsphere FS2 integrating sphere by valostore.fi. Results may be more inaccurate with especially throwy or floody lights.

For spectral information and CRI calculations I have an X-rite i1Pro spectrophotometer with HCFR for the plot and ArgyllCMS spotread.exe for the data. For runtime tests I use spotread.exe with a custom script and a i1Display Pro because it doesn’t require calibration every 30 minutes like the i1Pro.

Explanation of abbreviations

CCT = correlated color temperature, higher temperature means cooler (bluish)

CRI (Ra) = color rendering index consisting of 8 different colors (R1-R8), max value 100

CRI (R9) = color rendering index with deep red, usually difficult for led based light sources, max value 100

TLCI = television lighting consistency index, max value 100

CQS (Qa) = Proposed replacement for CRI, RMS average of 15 color samples

CRI2012 (Ra,2012) = Another proposed replacement for CRI, consists of 17 color samples

MCRI = Color rendering index based on the memory of colors or 9 familiar objects

x,y = coordinates on a CIE 1931 chart

After 35 seconds on turbo with a 18650 battery, my lights drops down to moonlight and doesn’t recover before switching it back off and on again. The backward mode cycling with a long press also stops working after overheating.

*Spectral distribution

*

Color rendering

Beam and tint



Tint in different brightness modes is consistent. Mode 1 = moonlight, Mode 7 = Turbo.

Runtime

High 2 and Turbo



Medium 2 and High 1

