Astrolux SL01

Astrolux SL01 specifications

There was a day when I hadn’t thought about my bike in over a year. You get caught up in work, other hobbies, raising your young children, and it can kind of just slip away. When I was asked to review this light, I thought it a good idea to jump up, brush the dirt off and ride my bike for the first time in WAY too long. Fortunately, it was like riding a bike. I hadn’t forgotten anything. The Astrolux SL01 on the other hand, was a little more as if riding a bike was a perishable skill. The UI was different and took a little getting used to, but overall, was not out of the ordinary. The feel isn’t something you typically think of for a flashlight and the implementation of a light sensor makes perfect sense given the use, but nothing was unwelcome and features were executed quite well. Let’s dive in and see what they were able to bring to the table that makes this unit stand out among its peers.

Package quality.

The packaging is quite nice. There is a top flap opening box with the images of the light and the specifications printed on the sides. The box is black, which makes it mildly difficult to see the images. Everything seems very stiff and sturdy, partially due to the fact that the inside is also cardboard, where the actual light is housed. Underneath the cardboard insert is the USB-C cable, handlebar attachment and the manual.

Everything included in the box is as follows:

• Astrolux SL01
• Battery
• Handlebar Attachment
• USB-C charging cable
• Manual

Let’s get one thing out of the way. This is a specifically built bike light and not intended to be used as a handheld unit. While it functions perfectly fine as a handheld light source, the shape, ergonomics and the adapter on the bottom of the unit make it apparent that there is a purpose for this light and the pocket is not one of them.

That being said, the SL01 has a fantastic hand feel and makes me wish the adapter on the bottom were more easily removed. With the recent release of the Olight Arkfeld, the Wuben X-0 and other “peculiar” looking lights, I am finding that I am liking the change of pace. This peculiar-looking light has one distinct purpose and its skillset is showcased in its accessories and features. It is a bike light through and through.

No lanyard attachment and its available accessories (more on this later) further solidify this fact. It doesn’t need a bunch of knurling to increase grip in a tactical situation. What it has instead, is a smart ambient light sensor that when activated, will make it one of the easiest lights you could ever use. It completely takes control and lets you do what you are trying to do; ride that bike of yours. If you prefer not to use the smart sensor, they also have an optional USB-C corded remote control that gives you the freedom to use all of the options available without having to take your hands off of the handlebars. That was not sent for review, but the concept appears sound and if the quality is anything like the actual light it is used with, would be fantastic. If you do decide to use the physical light, instead of the optional accessories or the smart sensor, the switch is of the e-switch type. It has a soft rubber feel to it and a backlight that corresponds with the state of the battery and charging. Other than that, the only thing you will notice is the light to notify you if the smart sensor is active and the ambient light sensor. The spacing of the different modes is even and switching between them is a breeze.

The Body of the SL01 is quite smooth, completely void of all knurling and machining which would normally facilitate better grip and maneuverability. The anodizing is satin and can collect fingerprints quite easily. However, the design allows you to rarely touch the light. Everything seems well put together and I do not notice any discrepancies with the parts fitting together. This is thoughtfully designed and assembled. The tail is plastic, while the main body is aluminum and you can tell Astrolux took their time to make sure the finishes matched as closely as they could, even being different materials.

Now, keeping in mind this is a bike light, there needs to be a way to mount it. The SL01 comes with a plastic mount with just enough flexibility that you can wrap it around your handles and crank it down without feeling like any of it will break or bend. Sturdy yet flexible is the name of the game. When you do slide the SL01 into the handlebar mount, the sound of a satisfying click is all that you need to know that it isn’t going to budge. This gives you that click and with my test unit, there is not an ounce of play. It is stable and sturdy and removes all sense of worry. In the off chance there is a little bit of slop in yours or anything else is a miss, the Bangood page shows that Astrolux products carry a 1 year warranty and would take care of it promptly.

The LED in the SL01 is provided by Luminus in the form of the SST40. It provides a cooler white and, as per the usual with this mass produced LED, leans more on the “greener” side of tints. It is a highly efficient and dependable emitter, which explains why it is used so frequently. The green you see is found all over the beam, as it is hidden behind a honeycomb/smooth spot TIR lens. The flat honeycomb gridded lens over the TIR is designed to give you a smooth profile to your beam, instead of a definitive hotspot. The beamshot also gives you a very slight flat spot on the top, presumably due to the shallow hood present on the body. The temperature of the particular led came in at roughly 5600k and 68 Ra according to my Opple Lightmaster Pro. It was measured in Medium mode at 1 meter.

Dimensions: 

Weight: 

Flashlight size comparison with its competition

With no other bike lights available to compare the SL01 to, I brought out some newer lights that have been in photos recently for comparison, the Wurkkos WK03 and the Wurkkos WK15.

With a 1000 lumen limit, the spacing on the SL01 is quite nice, allowing you to move between multiple modes, depending on how much light you will actually need. If you are moving faster on your bike, just turn it on Ultra-High to give yourself more light and throw. Just cruising? Well, then you can extend your battery life if you find yourself not needing as much light. There is no moonlight mode, with the lowest setting coming in right at 100 lumens. This is perfectly adequate by my standards, given the purpose of the light.

Available modes: Low, Medium, High, Ultra-High, Smart mode (light sensor mode)

Available blinky modes: Flash

User interface:

From OFF:

• Press and Hold: Power on into last used mode
• Press and Hold 2 seconds: Smart mode (utilizing the light sensor on the top of the body)
• Double click: Ultra-High mode

From ON:

• Press and Hold: 2 seconds to enter Smart mode
• 1 click: Cycle through modes
• Double click: Ultra-High Mode

Mode memory:

• Yes, it has mode memory. And you can’t turn it off.

Shortcuts:

• To Ultra-High: Double click

Low voltage warning:

• There is a backlight on the button. It will illuminate blue if the battery is between 61 and 100 percent capacity, yellow if the battery is between 21 and 60 percent and red if between 1 and 20 percent.

Strobe/blinkies

• Cycling through your normal modes is the only way to get to the 

PWM

• PWM is visible on my cell phone camera as well as my Opple Lightmaster Pro

Additional info on the UI: 

• In Smart mode, the SL01 will utilize a light sensor on the top of the body and if there is sufficient light, will move to a flashing pattern. If the ambient light is poor, the main emitter will go into High mode (500 lumens). Additionally, there is a movement sensor that will keep the light going until it has not detected movement for 120 seconds.

The battery in the SL01 is not removable. The unit is sealed quite nicely with no exposed screws indicating easy removal of the internal battery. Given the capacity, I can safely assume that it is a 21700 cell, but I have no visual evidence for such information. It tested to 4034 mAh at 5V with my USB tester, and got there in 3 HRS and 6 MIN at 10W. I used the supplied cable and found that the included USB-C cable did have some play in it. It shook like it was old and worn, but there were no physical signs of use like wear marks or bent pins and it did not affect the charging cycle. The button will illuminate blue if the battery is between 61 and 100 percent capacity, yellow if the battery is between 21 and 60 percent and red if between 1 and 20 percent.

Lumen measurements

The runtime graphs were prepared using a purpose-built integrating sphere and an ExTech SDL400 logging light meter. The meter was calibrated to a known light source and the light was tested using its internal battery fully charged.

The graph for ultra-high shows the output dropping considerably due to heat, but it never felt that hot in the hands. It is easy to draw a conclusion that a thermistor is placed in very close proximity to the actual emitter, and thus, gets hot quickly. It does return to normal temps and continues shining along brightly.

Parasitic drain:

• Unable to test. The unit is sealed.

Battery Life: Runtime graphs

The runtimes on the SL01 are consistently higher than the stated specifications and I can’t quite pin it to anything in particular. Particularly in low, my runtime bested the spec by a staggering 4.5 hours. The measured times all match the 

ANSI FL1 standards: The runtime is measured until the light drops to 10% of its initial output (30 seconds after turning on). This does not mean that the flashlight is not usable anymore. The last column shows how long the light actually works till it shuts off. If there is a + symbol, it means that the test was stopped at that particular point, but the light was actually still running. This happens on certain occasions, with certain drivers, firmware, or batteries.

Peak beam intensity and beam distance measurements

The ultra-high figures were almost 20 percent high, and I think it has to do with the honeycomb lens. That lens style will provide more direct light and stop the emitter from flooding out as much.

Extra info: Peak beam distance according to ANSI FL1 standards: The calculated value of distance in meters at which the flashlight produces a light intensity of 0.25 lux. (0.25 lux is about the brightness of a full moon shining on an object).

All beamshots were taken at 70m with a Lumix G7 locked at ISO 6000 and ev 0.0

With no other bike lights specifically to compare it to, I used a couple of newer options that people may be familiar with that were around the same price or cheaper. 

Beamshots compared to the following flashlights:

• Wurkkos TS21
• Wurkkos WK03
• Wurkkos WK15

Astrolux SL01 for sale

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