Prometheus Alpha

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Prometheus Alpha ready made Review

Prometheus Alpha specifications

Brand/modelPrometheus Alpha Ready Made
Lumens700 lm
Beam intensity2900 cd (Cree MCE 4500K)
Battery config.1*18650
MaterialAluminum (Electroless Nickel plated)
Modes3 (default)
BlinkiesPossible (not by default)
ReflectorLedil Boom
Waterproof– (100 meters)
Review dateMay 2021


For many people Prometheus is a rather unfamiliar name, but deep inside the flashlight industry, it’s not. Jason Hui (the owner) founded Prometheus back in 2011, and has been in business for a decade.

They are based in the US and have a small team of people producing high-quality flashlights. The one in this review is the Prometheus Alpha (Ready-Made). This is only one of the few flashlights they sell ‘ready-made’ because most of their lineup consists of custom-made flashlights. The Prometheus Alpha is also available with different metals like Titanium, and even with Carbon parts.

Ready-Made lights are pre-assembled and ready to ship, they are not built to order. “

Package quality.

A simple white box with quite a bit of content. This is what’s inside the box.

  • The Prometheus Alpha inside a carton tube
  • USB Charger (Optional)
  • 3400mAh 18650 battery (Optional)
  • Spare o-rings
  • Nano oil (lubrication)
  • Basic instructions + Programmable driver explanation (UI)
  • Charger operating instructions

Flashlight in use

The Prometheus Alpha (ready-made) uses a forward clicky switch, including the Icarus UI. This UI was developed specifically for Prometheus flashlights (Darksucks) back in 2015.

Having a forward clicky means changing modes before you hear the click. You basically tap the switch instead of fully pressing it. If you’re not used to forward clicky switches, you’ll soon get the hang of it, no worries.

The Alpha comes with a titanium pocket clip preinstalled. Keep in mind that the way to insert your battery is by unscrewing the head and not the tailcap.

Tailstanding: Yes, you can make it tail stand

Build Quality, and Warranty

I currently have more than 100 flashlights, but when I looked at the pictures on the internet, I had no idea what to expect from an aluminum flashlight with electroless nickel plating. If I didn’t know the background on this flashlight, the manufacturer, price, or the electroless plating, I swear I would have said this to be a very cheap flashlight. I know that this is not nice to hear, but that was my very first impression was seeing it up close and holding it in my hands. Now I know more about the brand, the effort to design the flashlight, the nickel plating, etc, I can appreciate it more, and now, after a few weeks of playing with it, I’m totally used to it, and my initial thoughts have dried out. But still, titanium or any exotic metal would make this light look even better.

If you want to know more about electroless nickel plating, check this out:

The threads are super smooth and screw very nicely. The clip is made of titanium, so definitely no complaints there. Each part has been designed uniquely for this light so I do appreciate the craftsmanship and effort that has been put into this flashlight, for sure!

Darksucks / Prometheus gives a limited lifetime warranty. And if you want to know all details, I’ll refer you to the following page:

LED, Lens, Bezel, and Reflector

One more thing I wasn’t expecting is the LED. When I opened the box, I noticed an LED I wasn’t very familiar with. At first I thought I might have received one of the newest LEDs which I hadn’t encountered yet. Yes, that still happens these days. But alas, it wasn’t a new LED I had never seen, it was an LED that was popular before I even got into flashlight over a decade ago. The Prometheus Alpha is using an old Cree MCE that started its debut back in 2008, 1 year before I signed up for candlepowerforums.

Keep in mind that old LEDs aren’t always that bad in terms of beam profile or beam colors, and the MCE has a nice color temperature of 4500K, and thus a neutral white beam. Besides the neutral white Cree MCE, you can also choose the following:

  • Cree MCE 6500K
  • Cree XML 6500K and 4500K
  • Nichia 219C with 4000K.

I’m not sure if the XML is still available, because that’s also really, really, really old, and there are many other (and better) options available these days, with higher output and High CRI, like the Luminus SST lineup.

The reflector is a Ledil ‘Boom’ reflector that is a hybrid between a smooth and orange peel reflector. The beam is pretty smooth and nothing to complain about, although the LED itself has a visible change in hue between the hotspot and spill.

Dimensions and size comparison

  • Length: 145.8 mm / 5.74 ”
  • Head diameter: 30.5  mm / 1.2 ”
  • Body diameter: 25.2 mm / 0.99 ”


  • Empty: 129.6 g /  4.57oz
  • With battery: 178.8 g / 6.31oz

Popular Flashlight size comparison

Size compared to some popular titanium flashlights. You can see the difference in color. The Alpha has a shinier finish, being Nickel coated aluminum.

From left to right: Prometheus Alpha Ready Made, Jetbeam E1, Jetbeam DM25, Baivic V4+, Reylight Krystal, Sunwayman V10R ti+, Reylight Dawn.

The next picture is the size compared to some very popular Tactical Flashlights. Although the Alpha isn’t really a tactical flashlight but for the sake of size comparison, you get a better idea of how large it is.

From left to right: Olight Warrior X Pro, Prometheus Alpha, Thrunite TN12 v4, Olight M2R Warrior Pro, Fenix PD35 TAC.

The background is hard to get real white with shiny flashlights like these.

Driver & User Interface:

Prometheus uses its own, uniquely designed Icarus driver. If you’re interested in just the driver, you can get one at with a lifetime warranty. The firmware has been on the market since the launch in 2015, but it is likely going to fit most people’s needs.

Available modes:

By default, there are 3 normal modes + Turbo. Darksucks calls Turbo : 100% DA (Burst). DA stands for Direct Access. And 4 modes in the Advanced menu. (By default it has 2 mode groups, standard and advanced, that you can toggle in between, and both mode groups can be customized to your own liking with how many output modes you like).

To change between mode groups you have to enter the programming menu: 8 taps from Off. And then 2 taps.

  • Low, Medium, High, and Turbo
  • The regular menu cycle doesn’t include Turbo, and won’t be memorized

From OFF:

  • Half-press: change modes from low to high
  • Single-click:  (to last used mode, mode memory)
  • Double click: DA Burst mode (Turbo)

From ON:

  • Half-press: there is no half-press with a forward clicky switch
  • Single-click: the light turns off


  • To Turbo: double click

Mode memory:

  • Yes, but you can deactivate that in the customization-menu

Blinky modes menu:

  • Only when you activate them, not accessible by default

Low battery warning:

  • Below 3V it will start blinking every 5 seconds. Darksucks recommend to replace/recharge the battery at this point.

Lock-out mode:

  • None


  • Not visible by eye.

Firmware / UI Conclusion:

If you just want clicks and a set number of modes, the Icarus driver is all you need. You can set your own desired modes (between 1 and 7, because 8 clicks are used to enter programming mode), the number of modes, memory on/off, strobe, high to low, low to high, etc.

The programming modes are hard to remember without the manual. This is certainly not a pro. But back in 2015, this was probably one of the most sophisticated (non-electronic side switch) drivers out there. It’s still pretty impressive to have this many features in a driver, plus you get a lifetime warranty on the driver.

Details on how to use the programming mode:

Batteries & Charging

The Alpha can take protected as well as unprotected, button top and flat tops.

I got the kit, which includes a portable charger and a 18650 battery. The battery is a 3400mAh 18650 lithium-ion and is labeled as a Prometheus battery. They’re using a good quality battery, something like a Panasonic NCR18650B

The portable charger has 2 magnetic buttons that go on either side of the battery, positive and negative terminal. An interesting note, that the 2 probes have no designated positive and negative terminal. The charger can automatically detect the polarity. Although the specifications on the back of the package don’t show the charge Voltage for a NiMH battery, it should be able to charge NiMH and Lithium-Ion batteries.

During charge there is a solid red light which turns green when fully charged, and blinking red when there is a problem. The charge speed is 750mA max, but my USB meter shows roughly 700mA. For NiMH this is quick enough, but for a 5000mAh battery, that’s more than 7 hours of charge. But still, this is probably my new charger for on the road.


Lumen measurements:

All output numbers are relative for my home-made Integrating Sphere. It is set up with an Extech SDL400 Lux Meter for measurements including a Kenko PRO1D ND-16 filter. The base measurement is done with a Convoy S2+ that has been tested at 255 lumens.

All of my readings were taken from a fully-charged Prometheus 18650 3400mAh.

Amps were measured with a Fluke 77III, at the tailcap.

ModeAmps @ startSpecs@ 30 sec@ start
DA Burst (Turbo)3.35A716738


The runtime test was done with the 50cm integrating sphere, including the Kenko Pro1D ND-16 filter and Extech SDL400 data logging Lux Meter.

Burst (Turbo) starts at 738 lumens and starts to drop very slowly till about 4 minutes 30 seconds when it starts to drop faster till it reaches around 230 lumens. It then starts to ramp up slowly (probably because the Voltage starts to drop) till it reaches around 310 lumens 2 hours 42 minutes. Around 3 hours and 8 minutes is about 20 lumens. So total runtime is roughly 3 hours for DA (Burst) / Turbo mode

High starts at around 514 lumens and is pretty stable for about 7 minutes 30 seconds when it starts dropping to about 225 lumens. It starts to slowly increase 282 lumens at 2 hours 47 minutes. Around 3 hours and 16 minutes it dropped to about 15 lumens. It then starts to produce a few lumens for about 1 hour. Enough time to replace the battery.

Medium starts at around 133 lumens and continues for about 7 hours and 30 minutes when it drops from around 116 lumens down to about 15 lumens around 7 hours and 53 minutes.

I must say that the output is actually really low for an 18650-light these days, especially after the first output drop. Having a stable output of 700 lumens should be doable these days with the right driver and LED, including High CRI.

Throw Measurement

Measurements were taken indoors at 5 meters with a professional Hagner E4-X Lux Meter at 30 seconds.

Low125 cd2224
Med650 cd5156
High2500 cd100109
Turbo (DA burst)3500 cd118129



For the following beamshots I used a Canon EOS 5D Mk2 and a 50mm lens. manual settings: ISO1600, 1/4sec , F4, 5000K. Beamshots were shot on different days, therefore the different background

The shed is about 65 meters / 71 yards away. 

Disclaimer: This flashlight was sent to me for review at no cost by Darksucks. I have not been paid to review, nor have I been holding back on problems or defects.

Final Verdict


  1. Highly customizable UI
  2. Neutral white LED with medium High CRI
  3. A flashlight with a long history.
  4. Good beam profile (smooth)


  1. Quite dim compared to contemporary flashlights
  2. Uses a very old LED
  3. The programming menu can be a little confusing
  4. Electroless Nickel plated finish isn’t my cup of tea with this particular design

Explanation on star ratings:

1 Avoid: my phone flashlight would be a better choice / 2 Poor: significant defect or issues, much better options available at the same price / 3 Average: some defects or issues / 4 Good: recommended (minor issues) / 5 Great: highly recommended

Reviewer Marco
Author: Marco

3.5 stars: ★★★⋆

There’s things I like about the light, and there’s things I don’t like about it. I like the fact that this flashlight has a long history and is designed by a dedicated flashlight builder. The things I don’t like are the dated LED and the low output.
This is probably not a flashlight a regular user would be looking for, but if you are interested in a flashlight with a history, and a story, from a USA-based manufacturer, definitely take a look at Prometheus lights. However, I would advise getting the titanium version instead!

Prometheus Alpha For Sale

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