Review: Astrolux S43 2600 Lumen Flashlight

This is a review of the Astrolux S43 flashlight. It is a high-powered light that takes a single 18650 or 18350 battery. Four LED emitters, either XP-G3 (cool white) or Nichia 219C (high CRI neutral white), produce up to 2600 lumens in turbo mode. This review covers the Nichia 219C version.

The light was provided by Banggood for review purposes. I receive no other form of compensation, and all my reviews are independent. You can find the Astrolux S43 light on Banggood’s site here, along with further details:

There is a discount code which brings the above light down to $29. Use code 9f1297 at checkout.

There is also a copper head version of the light, the Astrolux S43S. You can find details here:

There is also a discount code for this light, also $29. Use code BGS43S.

You can watch my Youtube video review here:

Overview:

Oh, the sweet high color rendition light of the neutral white Nichia 219 emitters. You can light up the night, and turn your local piece of it into day with this light. Because, we know that dark is bad, and it’s our job to get rid of it. The sun just doesn’t work hard enough, half the time.

The Astrolux S43 and S43S are updated versions of the Astrolux S42 and S42S. The main complaints about the S42 was its slow user-interface. This issue has not only been addressed, but blown-away by the introduction of the NarsilM v1.3 firmware. This is a highly customizable user interface, but is best known for its easy-to-use and responsive ramping mode to quickly select whatever output you wish.

An older version of Narsil is used in the BLF Q8, so if you have that light, you’ll be familiar with this interface. It was one of the main selling points of that light, and no doubt it will be for the Astrolux S43 as well.

Besides the user interface, what impressed me most is the extremely bright output. The four Nichia 219C emitters generate up to 2600 lumens on a fully-charged high-drain 18650 battery. I used the Samsung 30Q for my tests. Banggood lists the output as 2100 lumens, which is lower than what I measure. However, I am measuring directly after turning on the light, and using a fully charged cell. It is quite possible that the output will drop to 2100 lumens after a bit of use.

A FET+1 driver is used in the light to achieve this high output. A FET driver tends to lose about a third of its output by the time the battery is half-drained. This is what it takes to get such high output without a costly boost driver.

The older S42 used only a FET driver, which is less efficient at lower output levels. The S43/S43S addresses this issue by using a FET+1 driver, which includes a linear driver for lower output, and it is much more efficient and well regulated (output does not drop as the battery voltage drops).

In this review, I am only going to discuss the Astrolux S43, which is a fully aluminum version of the light. I will discuss the S43S in another post, as well as do a comparison with some other common lights. The S43S is most the same light, but with a copper head for better heat absorption.

The S43 gets hot quickly on turbo. However, it does have thermal controls to decrease output when the light reaches about 60C. This takes less than a minute, and the head becomes uncomfortably hot after about 30 seconds. There are electronic and manual ways to lock out the light when transporting it in a pack, so that it doesn’t accidentally come on and burn your bag. Yeah, that wouldn’t be good.

The thermal control will not step-back up if the light cools down due to a change in wind or external temperature. You will have to ramp up the light if you find the thermal step-down has gone too far. Or, you can program the thermal settings to be less restrictive than the default. I find the default to be decent, although it overshoots a little too far in my opinion.

Finally, this light has a built-in micro USB charging port. So, you don’t need a separate charger to charge your battery.

Specifications:

Output: Very flexible user interface. Can be used with either programmable fixed-modes, or the smooth ramping interface. Brightness of ramp is from 0.1 lumens to 1400 lumens. Double-click for turbo of 2600 lumens.

Throw: 184 meters. However, this is a very floody light, and practical distance is much less. Consider this a “wall of light” out to about 50m.

LED: 4 x Nichia 219C neutral white. Or 4 x XPG3 cool white.

Tint: Nichia option is 4600K high CRI neutral white.

Size: 120mm long (18650) or 88mm (18350), 27mm diameter.

Weight: Up to 141g with 18650 config, pocket clip, and 18650 battery. The S43S weighs an additional 60g, due to the heavy copper head.

Construction: Aluminum body with anodized coating. Drop-proof (1.5 meter). Water resistant to IPx6 (strong jets of water are okay, but do not submerge). Feels very solid and well built.

Battery type: High discharge 18350 or 18650. Flat tops recommended, but there’s room for a button top. Since this benefits from high-drain cells, a protected battery would not give good results on turbo. I estimate it draws up to 10 amps with a fully-charged cell.

Springs: Tail uses a double-spring for high current conductivity. The heads uses a copper post to minimize resistance.

Over-discharge protection: Yes. The light will flash a few times and step-down in brightness, as the battery nears empty. It will continue to do this until it eventually shuts off. After the first couple of step-downs from maximum, I measured the (resting) battery voltage at 3.08v, so there’s no risk in over-discharging your battery.

Output: From a moonlight of 0.1 lumen, to a turbo of 2600 lumens. Note that max output drops as your battery depletes.

Beam profile: Floody light.

Heat: Gets hot quickly on turbo, but reduces output when temperature limits are reached. You can program the temperature to step-down, or just use the default.

PWM: I’m sure this must use PWM to regulate output with the FET driver on some of the modes, but it must be very high frequency. It shows no signs of PWM.

Tail-stands: Yes. The tail has a tripod mount in it, which the glass hammer can screw into. If you want to use the glass hammer, it will not tail-stand.

Standby drain: 22uA with indicator light off (15 years), or 94uA with indicator light on (3.6 years)

USB charging: Yes. Fully charges an installed battery to between 4.18v and 4.20v. The switch uses a red indicator when charging, and turns off when done.

Contents:

Astrolux S43 4x XP-G3 or Nichia 219C LED Flashlight
18650 body tube
18350 body tube
Spare o-ring
Glass hammer
Lanyard
Pocket clip
English manual

Operation:

The Astrolux S43 and S43S use a user interface that is driven by the NarsilM v1.3 firmware. This is a very flexible UI, that is primarily praised for its quick and easy ramping output. Though, you can also program it to use fixed mode outputs. I would suggest using the default ramping interface, unless you are certain you prefer the way it implements modes. In my opinion, the fixed mode interface is rather unintuitive, and likely to confuse most users. The ramping interface is very intuitive, and pleasing to use.

The Astrolux S43 has an electronic side switch, that is illuminated green whenever the light is off. You can program the the side light to always be off, but it takes very little current to operate and its very handy as a locator in the dark.

The side switch light glows red when charging the light. The look of it reminds me of a certain dark lord of Mordor. It glares red and angry, until the light is happily fully charged.


Anyway, back to the user interface. I will just describe the ramping style, as you can go to the product page linked at the top of this review to download the Narsil documentation.

It’s simple.

Single-click to turn on the light. It will turn on to whatever output the light was using when you last shut it off. Press and hold the switch to ramp up the brightness. If you overshoot, just release the switch and press and hold it again to ramp down in brightness.

Double click from either off or on enter turbo mode.

From off, press and hold the switch to start ramping from moonlight. I find this is the most useful way to use the light, since I know I’m not going to blind myself.

That’s basically it. There are also strobes, but by default they are turned off. Leave them off. Creatures that inhabit the dark get very angry when you use strobes, and you wouldn’t like them when they’re angry.

Other useful features of the user interface are as follows.

Triple-click for battery check mode. The light will blink the battery voltage. For example, it will blink 3 times, pause, then blink 6 times. This means the battery voltage is 3.6v.

Quadruple-click to lock out the light. This prevent you from setting your knapsack on fire if the switch is pressed while transporting it. Generally, that is a good thing. Quad-click to disable the lock-out, when you do want to burn stuff. You can also manually lock out the light by slightly unscrewing the tail cap.

Quintuple-click to set the light into momentary mode. You can then just press the switch to temporarily turn on the light while you hold the switch down. To disable, you have to unscrew the tail cap a little.

To temporarily turn off switch LED, press and hold, then quickly single-click. The eye of Sauron will no longer watch you, until you turn the light on again. You can also permanently disable it with a programming option.

My impressions:

Pros:

- Extremely bright for a 1x18650 (or 1x18350) light. Sends out a wall of floody light.

- Excellent user interface.

- Excellent tint and beam profile with the 4 x Nichia 219C LEDs.

- Built-in micro USB charging.

- Well constructed.

- Illuminated switch makes the light easy to find in total darkness.

- It has very low standy current, even with the illuminated switch.

- You can program the moonlight mode brightness, and it can be very dim.

- Supports 18350 and 18650 battery types, and includes both bodies.

Cons:

- Body knurling is limited to tail. This makes the grip a bit slippery. If you install the pocket clip, this allows for much greater grip, so the smooth body isn’t such an issue. However, I do wish they applied a bit of knurling or something.

- Banging the bottom of light will sometimes shut the light off. This is because the battery can break contact at the positive end of the light. It’s not an issue in normal use, but if you drop the light on its tail it could shut off. This is the same issue with the BLF Q8 light, and seems to be a common problem with some lights that don’t use springs at both ends.

That’s all for now. Thank you for reading.

:+1: :+1: :+1:
Awesome reviews,clear and clear.
adding a lot of points to the S43,
which was not very popular at first.
I think I will seriously consider whether to buy S43.

I think if you liked the look and output of the S42, but hated its user interface, you’ll really like the S43.

I like that the S43 includes both the 18350 and 18650 body tubes, rather than separately like it was with the S42. Though, IMO, if you use this light on turbo (and why wouldn’t you), you’ll probably want to stick with 18650 so you get some reasonable run-time.

I could not get close to 2100 lumens on my Nichia version. On another thread they reckon that the Nichia will only produce about 1600 lumens on turbo and that agrees with what I measure.

I don’t claim my output measurements are 100% accurate (they could be off by +/- 10% for example), but I can confidently state that it is way brighter than 1600 lumens. I could be high on my measurements, especially since I didn’t do an ANSI FL1 measurement; in that case the 2100 lumens that Banggood states may be more accurate.

I did notice that it falls from my 2600 lumens estimate very quickly. I could only achieve that on a fully charged cell within the first few seconds after turning it on. For ANSI, I think 2100 lumens is probably the number to use, assuming you don’t hit the thermal step-down before that.

1600 lumens seems way too low. I couldn’t be off that much. Are you sure you weren’t in thermal step-down?

Great review thanks!
Love the LOTR reference!

I wonder if the estimate output being tossed around for the Nichia was based on the 10A S42 vs the 15A S43. I have both but don’t own a sphere. I also visually compared my Nichia S43 to my CW S42 on turbo and the S43 Nichia seemed brighter at short distance. Put that in your pipe and smoke it!

While I was at it, I did a bit of LEGO play, and the 18650 body tubes and tail caps do lego between the S43 and S42 and work perfectly. The knurling on the S43 tailcap is minimal, and close enough in pattern and far enough from the tube’s knurling that they are a good match and only show any difference upon close inspection. Black Ano color is a match too.

The S41/S42 18650 tube is 3mm shorter than the new S43 tube. That’s not a problem if you’re running unprotected batteries. I like the newer S43 tube for its ability to fit my Acebeam protected 18650 battery. That’s also the only battery with PCB I own capable of triggering turbo mode. My others could not, which makes sense since it pulls 15Amp, most PCB 18650 cutoff is well below 15 Amps.

I notice none of the S43 include a USB cable. Do you think they believe everyone has one by now? They may? Lol

I noticed yours has a decent gap on both ends of the body tube. I just received mine and I’m a little disappointed that the gap is there and it’s large enough that the thread grease leaks out. Both tubes, the 18650 and 18350, are like this.


I didn’t even notice those gaps until you mentioned it. Thanks so much lol

Those that own the S42 and the S43… I have various S42… and yes, Turbo is impressive for a few seconds… but the usual Non-Turbo-Light is sort of ‘standard’ EDC-brightness (yes, I know, much of the lumens are ‘wasted’ in the flood beyond the center)… how does the S43 compare to the S42 regarding this Non-Turbo-Brightness?

The non-turbo brightness (“high” on the ramping scale) is about half the output of turbo (“double-click”). I measured 1400 lumens, though that drops rapidly as the battery declines. Basically, it’s similar to single-LED XP-L lights that are driven from a FET driver.

As far as sustainable output without thermally ramping down, it’s down around the 300 lumen output, typical of other small lights. The XPG3 configuration would probably do better, since they generate less heat than the 219C.

You can turn off thermal step-down, though you’d have to be careful not to let things get too hot.

As for the S42, I find it eventually gets hot on all modes above their medium output. It’s probably similar to the S43.

With default temperature settings mine can’t retain 250 lumens in 23°C room temp without additional cooling. Steps down to ~100 lm after 15 minutes.

The default thermal controls overshoot, IMO. But if you feel the light after it settles down for awhile, it will only be warm, not hot. You could try raising the thermal setting in the programming mode, or turning it off entirely. Or just turn up the light again when it overshoots. I’m not sure if there’s a setting for controlling how quickly it steps down. That would be nice, but I’m not sure if Narsil has something like that.

I find the thermal controls adequate, and certainly better than a timed setting, but it’s nothing like the PID that Zebralight uses (which is very responsive both down and up, and maintains temperature almost exactly).

If you want to use the S43 on high output a lot, consider the S43S instead. It has a large copper head, and I find that absorbs a lot of heat. Takes at least twice as long for thermal controls to kick in, compared to the S43. I plan to do a comparison review soon.

thanx in advance, will read tomorrow.

Differences with the Astrolux S43S (copper head version), posted to this thread:

I finished my video review. Added to the first post in this thread.

Hello,
Great review, thanks. I’ve bought one on BG.
Can you help me to understand why the turbo doesn’t work with protected 18650?
My S43 works fine except turbo mode with full charged protected battery Sanyo NCR18650BF. i double click to enter turbo mode , the light blink once and stop working. i have to unscrew the tail cap to reset the problem. With samsung INR 30Q the turbo mode works.
Is there a protection in the S43 that detect the battery can not supply enough power? but why to stop the light? it should works at lower level.

Sounds like the protection circuit on the battery is sensing the huge current draw and, thinking it’s a dead short, shutting down the output.

Yeah, that would be my guess too. The S43 on turbo draws a large amount of current. Around 10 amps or more? You really need an unprotected high-drain cell for proper performance.

@jintian, since the light draws a lot of power on turbo, your protected Sanyo NCR18650BF detects the very high power draw, and shuts itself down.

The 18650 you want is this:

I have exactly the same problem with protected cells. It's due to the protection circuit in the cell itself cutting the power.