Review: Astrolux S43S 2100 Lumen Flashlight

This is a review of the Astrolux S43S flashlight. Okay, to be fair, this is a comparison review between the Astrolux S43 and the Astrolux S43S, with the Astrolux S42S thrown in just for fun.

In the above picture, the Astrolux S43 is on the left, the Astrolux S42S is in the center, and the Astrolux S43S is on the right.

For the full review of the Astrolux S43, please read the following thread:

I recommend you read that thread first, for much more comprehensive information than is contained in this thread.

The Astrolux S43/S43S 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. (Though that quickly fades to the advertised 2100 lumens.)

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 S43S light on Banggood’s site here, along with further details:

There is a discount code which brings the light down to $29. Use code BGS43S at checkout.

There is also a regular version of the light, the Astrolux S43. You can find details here:

There is also a discount code for this light, also $29. Use code 9f1297.

Overview:

Okay, you read the Astrolux S43 thread I linked above, right? Then what are you reading this section for? What you really want to know is what is the S43S and what makes it different than the S43.

Differences

Basically, the Astrolux S43S is the same as the S43, with one key difference: copper. The aluminum head of the S43 has been replaced by a chunky slab of shiny copper metal. The rest of the light is aluminum, just as with the S43. The user interface and extras you get are the same.

Why copper? Because it soaks up a lot more heat than aluminum can, and transports that heat to the surface a bit easier than copper. This allows the S43S to maintain a high output for longer than the S43, before thermal controls start to drop output to protect the light and user from burns.

And since this is a very bright light that gets hot quickly on high modes, extra run-time is a nice feature to have. Plus, that copper looks nice to some people.

In my testing, the copper allows the S43S to run approximately twice as long on a high mode, compared to the S43. On turbo (2100+ lumens), that means about 1-2 minutes before thermal step-downs begin, compared to about 30-60 seconds for the S43.

When the thermal controls kick in, the light is uncomfortably hot to hold at the head. Though, the body remains much cooler, so holding it is no problem. The copper head feels hotter than the anodized aluminum to the touch. Perhaps that is just because copper conducts heat into your hand more easily. If you’re man enough, I suppose you could keep a tight grip on the head to keep the internals cool a bit longer, and extend your run-time on turbo.

But nothing comes for free, so what do you give up? Weight. Copper is heavy, and so the Astrolux S43S weighs significantly more than the regular S43 aluminum version. The S43S weighs an additional 60g, due to the heavy copper head. This puts it at a total of 200g for the 18650 configuration, with a battery installed. In my opinion, this is a little heavy for EDC pocket carry, though it’s still light enough to carry in a coat pocket on walks.

By the way, the Astolux S43S bezel is supposed to be crenelated, just like the S43. My review copy was incorrect in that regard.

Conclusion

Both the Astrolux S43 and S43S are nice lights, with very high output and an excellent user interface. If you’re someone that likes to run their lights on high output a lot, then the S43S makes more sense. If weight is a more important concern, then the S43 is the one to get.

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

Thanks for the review and comparison. Good to know that the copper is larger than the one on the S42S. For me, the heavier the copper the better, because that means better thermal performance and more practical use for high modes.

Yes, the S43S is a lot better at absorbing that heat. Once it starts to step-down, though, it tends to overshoot to the low-end like the S43 does as well. You’ll need to turn it up manually if you find it has throttled too far. As with the S43, I find the thermal controls to be decent and get the job done, but they’re a bit too aggressive.

My tests were tail-standing, with no fan. I might try the “hand-sink” method to see if that can keep it operating at a high mode indefinitely. The copper version should have an advantage, due to better heat-transfer.

This is disappointing. What about the timed stepdown, is that any better ? I think this is an option in Narsil firmware.

Yes, you have a number of options to program different thermal settings if you don’t like the default.

Yes, have you tested it? Can you describe how the timed step-down functions (what brightness does it go down to etc) and does it a good job of preventing overheat?

IIRC, the timed step-downs go down to about half brightness. They can start from 1 minute up to 7 minutes. I wouldn’t go more than 3 minutes, even with the S43S.

You can also adjust the temperature that the automatic step-downs start. However, all that really does is delay the inevitable.

I think the automatic controls are the better option, because on a cold night outside you could operate the light on maximum much longer.

Keep in mind that maximum (or “turbo”) isn’t really meant to be used as a common mode. It’s not part of the normal ramp. You have to double-click to jump to turbo. The highest ramp output is about half what turbo is. I think they do this because turbo makes things get hot very quickly. Yes, it’s fun, but it’s not really that practical on a small light.

Used normally (i.e, under 1000 lumens), it takes much longer for the light to heat up, especially if you’re holding it and sucking away some of that heat into your hand.

Bottom line is that this is a compact light with a lot of output. There’s just no way to control the heat from 2100+ lumens in such a small light. Think of turbo as more of a “burst” mode than something you’d use regularly. It’s there to impress your friends and annoy your neighbors.

Thanks for the comparison and information!

What I notice here is the height/length difference between the S42S and S43S. I had measured my 18650 tube in my S43 to be 3mm longer than the S41/S42 tubes however there’s also a huge difference in head size, the S43S having so much more mass. Pretty great actually considering the tariffs right now on scrap copper coming into China.

Thank you soo much for explain me the light, i’m very glad about that! But let me ask you which color version is the brighter?
Thank you! :wink:

I believe the cool white is brighter.

I just posted a comparison pic with a few different lights; BLF A6, S42 and S43S with 18350 tubes to another thread, here it is again;

That’s a good representation of the mass of the new S43S head. Thanks@!