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Reviews > Lighting > Flashlights - LED > Princeton Tec Genesis Light > Test Report by John Waters

March 03, 2009



NAME: John R. Waters
AGE: 59
LOCATION: White Lake, Michigan USA
HEIGHT: 5' 9" (1.75 m)
WEIGHT: 178 lb (80.70 kg)

My backpacking began in 1999. I have hiked rainforests in Hawaii, Costa Rica, and Puerto Rico, on glaciers in New Zealand and Iceland, 14ers in Colorado and Death Valley's deserts. I hike or snowshoe 6-8 miles (10 km-13 km) 2-3 times weekly in Pontiac Lake Recreation Area, with other day-long hikes on various SE Michigan trails. I also hike in Colorado and am relocating there, which will increase my hiking time and trail variety tremendously. My daypack is 18 lb (8 kg); overnights' weigh over 25 lb (11 kg). I'm aiming to reduce my weight load by 40% or more.



Manufacturer: Princeton Tec
Year of Manufacture: 2008
Manufacturer's Website:
Listed Weight: 5.5 oz (156 g) - including batteries
Measured Weight: 5.25 oz (149 g) - including batteries
Case Weight: 0.6 oz (7 gm)
Length: 5.25 in (13.34 cm)
Diameter: 1.125 in (2.86 cm)
Colors Available: Black, Green/Silver
Color Tested: Black

Light Output: 47 Lumens
Lamp: 3W Maxbright LED

Warranty: "Princeton Tec warrants this product to be free from defects in workmanship and materials under normal use for as long as you own this product. This warranty covers all of the component parts of the product except batteries. This warranty does not cover deterioration due to normal wear or damage due to misuse, alteration, negligence, accidents, or unauthorized repair. Princeton Tec will repair or replace parts which are defective in workmanship or materials..": (in part from the included instruction sheet)
Genesis LED Light
Princeton Tec Genesis LED


I received my Princeton Tec Genesis LED Flashlight today. My last most favorite flashlight ever was a "smoke-eater" all aluminum, red, waterproof unit that I trusted my life with when I entered smoke-filled buildings during my crazy volunteer firefighting days. I messed it up by leaving batteries in it and never was able to clean it out. I've been looking for a bright, reliable flashlight ever since. I've purchased LED headlamps and like the fact that they have no center blackout area. So when I had a chance to test the Genesis, I was quite excited because I'm an engineer and testing electronic gadgets is such a favorite thing to do.

The Genesis looks great. The center of the light has a rubberized grip section and feels quite nice to hold. With the belt clip and two batteries installed, the Genesis weighs in at 5.25 ounces (149 g) on my scale. The Web site says 5.5 ounces (156 g), so we're pretty close to spec. It has a nice solid feel.

The Genesis arrived in a blister pack that I cut open with scissors. A belt clip ring is already installed. Two alternate accessory rings (Princeton Tec calls them "tail rings") are included that can be mounted at the rear of the flashlight just ahead of the battery access cover. The package also included a fabric holster with a fixed elastic belt loop and three color lenses (red, blue and green).

The red and green are for improved night vision and to stop night blindness. They say the blue one is for spotting blood ... interesting.

The primary use of the blue lens is for search and rescue at night, since Princeton markets heavily to police and fire services. The military use is for both rescue and hunting wounded prey. By the way, night hunting of coyote is legal in Maine, as is hunting wild hogs and gators in South Carolina, and I'm sure there are other special cases. Apparently there is more of a use for a blood tracking blue lenses than I imagined. Knowing this, I am going to have to head up to the acres on our ridge and check out some of the kill areas where there is frequently bones from fresh deer kills by, I think, coyotes or mountain lions.

Of the three tail rings: one has a belt clip, one has a ring for use with a carbineer and one is just a plain ring. I suspect, I'm going to be using the belt clip most of the time. But again, the holster only holds the flashlight, so carrying the extra tail rings and the lenses does really have issues.

The on/off switch is a rubber covered push button at the rear of the unit that is 1/2 inch (1.3 cm) in diameter. It can be pushed without clicking to flash, and pushed until it clicks to keep the light on until the switch is pushed in again to turn it off.


There was a one page (front and back) sheet of instructions enclosed with the Genesis. The instructions are in English, French and German. The bulk of the instructions covers installation and care of the batteries. There is a graphic section to highlight the operation of the light , information about the Lifetime USA Warranty (10 Year International Warranty) and Princeton Tec's return policy. The directions are very straightforward and easy to read.


Genesis Light compared to sunglasses
Genesis LED Light Size Comparison
I have to admit, this little thing is really bright. I have a 1 watt (total) LED headlight from Princeton Tec that has 4 LEDs and I thought that was bright, but this is REALLY bright. The Web site says it will broadcast a beam to 84 meters (275 feet) and at first look it appears to be about that when used in pitch black when pointed down our 650 ft (198 meter) driveway and pointed to our 100 ft (30.48 meter) high cliffside. I'll do more exact testing in my field review.

I took the lamp cover off to see how the lenses fit and removed the tail cover to put the batteries in. Since this unit is supposed to be waterproof to 1 meter (3.8 feet) Princeton Tec uses "O" rings to seal these covers. My concern at first use is what will happen to these "O" rings, since they are really thin and small. Since Princeton Tec did not include any extras, I'm not sure where I would find replacements. So that will be something to look for over the next few months.

I installed the CR123 3-volt batteries that are included in the blister pack. The included batteries are Lithium Ion but they are not rechargeable. An Internet search found the least expensive CR123 to be about $1.53 and usually the brand names, like the included SANYO's, are about $2.85 each. The batteries are supposed to last 120 hours according to the website. The blister pack and the single sided single sheet instructions say the "overall burn time" is 20 hours and regulated burn time is 1.70 hours. That is quite a difference. I guess I am going to have to find out what the actual values are. It's a sign to me that there is a lack of communication between product engineering, packaging and marketing. The buyer should never be presented with such conflicting information. I'm thinking now that the 120 hours is the LED burn time (until the LED needs to be replaced), but I'm still not sure what the two different 20 hour and 1.70 hour burn time specs are. With no spec on the LED I have no idea. I would like to know the manufacturer and SKU for the LED itself and how to replace it.

I spent several minutes trying to figure out where to store the three accessory lenses. They were in the blister pack in a rolled up plastic bag and now I needed to think of how I am going to carry them with me and not scratch them up while having easy access to them. They don't store in the flashlight or the holster in any way I can see. I guess their storage is left up to me. I'm not sure how I'm going to do that and not lose or damage them. I hope that Princeton will provide some useful external pouch on the holster in future versions.


Since I am going to do so much testing, I am going to spend about $30 and get myself a CR123 charger and a couple of rechargeable batteries. I've used AA and AAA Lithium rechargeable for years. It's so much less expensive and so good for the environment to not be tossing away batteries all the time.

Thus, this little guy shall get a good going over and be put through its paces. Let the testing really begin.

See below the results of my first two months of testing the Princeton Tec Genesis LED Light.



During the past two months of testing, all of my activity has been in Colorado between 5600 ft (1700 m) and 12,000 ft (3700 m) above sea level. I've used and carried the Genesis LED Flashlight at these altitudes in temperatures from 1 F (-17 C) to 75 F (24 C). And, of course, it was dark; varying from moonlit cloudless nights, to nights when the clouds were backlit by a full moon. I used the Genesis for nighttime hiking and for evening outdoor activities and specifically for testing distance and brightness. Heck, I even used it in our local Christmas parade (I'll explain later).


What I am interested in as a user is:

1. How far does the light beam go?
2. How wide is the beam for each color lens?
3. Is the light useful? Color, coverage, flickering, etc.
4. How long does the battery last and is there a difference between single use batteries and rechargeable in this device?

5. What temperatures will it perform in?
6. Is it waterproof? Snow proof? Drop proof? Sit-on-it proof?
7. How do the colored lenses perform?
8. How useful are the attachments?

During my first two months of testing, I've determined the following:
Comparison of Light
Comparing Genesis' Brightness
1. How far does the light beam go?

Pretty far. Impressive for something so small. In pitch black (hand not visible in front of face dark), I can illuminate the side of hills on our ranch that are 250 to 300 ft (76 to 91 m) away with the clear lens and 200 to 250 ft (61 to 91 m) away with the blue lens. I could report a greater distance, but when I report something like this, it'll have to be useful illumination. So at this distance, I can easily make out trees, rocks, and hopefully a bear or mountain lion.

By comparison, see image left where I have the Genesis (on the left) and a 44 Lumen Xeon headlamp (on the right) side by side. I'm standing about 100 ft (30.5 m) away. The Xeon headlamp is powered by 4 D cells, the Genesis by a CR123 lithium button battery.

2. How wide is the beam?

There is a difference between a beam produced by a regular bulb/reflector and an LED/lens. The "flashlight ring" produced by a bulb/reflector has dark space in the center and dark space in the rings around its beam. The LED/lens pattern is "smooth". There are no dark circles or voids. The light is white throughout the beam. The beam shining 250 ft (76 m) away or so is about 30 to 40 ft wide (9 to 12 m). I'm going to try and get more specific with these measurements in the final report. The difference can be seen in the beam width for each colored lens by looking at pictures #2, #3, #4 and #5. For these pictures, taken at 1/3 second and f2.5 on a Canon digital camera, I am about 30 f (9 m) away from a juniper tree with a solar landscaping light under it. I am holding the Genesis at headlight height for me (about 69 in. or 1.8 m) and pointing the beam down just to the lower right of the solar light. This is a good indication of how bright and wide the beam of each color is.
Genesis Blue Lens
#2 - Genesis Blue Lens
Genesis Clear Lens
#3 - Genesis Clear Lens
Genesis Green Lens
#4 - Genesis Green Lens
Genesis Red Lens
#5 - Genesis Red Lens

3. Is the light useful? Color, coverage, flickering, etc.

The distance and width from the pictures above indicate that the Genesis can be quite useful for hiking and camping as well as for emergency responders and professionals. There is no flickering. The colors are uniform using each of the lenses provided (blue, green, red and clear).

We had a Christmas parade here in Canon City, Colorado in December and I was part of the Chamber of Commerce group that wanted to get the idea across that we were "points of light" for the community. So we all walked next to or rode on a float and flickered flashlights into the crowd as we paraded down Main Street. I was surprised at how the spectators, standing maybe 40 ft (12 m) away, were reactively putting their hands up to cover their eyes when I hit them with the light from the Genesis. The Genesis was brightly lighting up reflective signs the same distance away. This light is quite bright for such a small package.

4. How long does the battery last and is there a difference between single use batteries and rechargeable in this device?

I'm still using the original battery. I estimate the Genesis has about 5 hours of total use so far. I can't control the brightness. It has just one level. The Genesis is either on or off, but the large, gasketed push button on/off switch on the end of the tube makes it quite easy to momentarily flash the LED. It's so comfortable to do so that I can easily send Morse code pretty quickly, probably at about 6 or 7 words per minute (I can handle Morse at up to 40wpm on air with an electronic keyer). It seems a little less bright after 5 hours, but it is still almost as bright to me as when I first turned it on. Without having a light meter and doing controlled tests, I can only estimate.

I have not purchased a CR123 charger, but I will do so for the next part of this report. I'll report on times for both types of batteries. The trick will be to not miss the turn-down moment when the device reaches its specified .25 lux at 2 meters (which is moonlight). Timing will be important since I do not have a light meter and alarm to record the moment.

5. What temperatures will it perform in?

Being subjected to sub-freezing temps didn't seem to affect the Genesis. The case and lens came out unscathed at 1 F (-17 C) while some other equipment I was using at the same time just did not like the wind chills down to -25 F (-31.7 C) and the plastic straps and facing material broke or chipped. The Genesis held up and its LED worked fine. Of course, it performed well at normal temperatures. What I cannot report on is battery life or LED life cycles at different temps since each test would have to be done under controlled conditions for the entire 20 hours specified for normal battery use.

6. Is it waterproof? Snow proof? Drop proof? Sit-on-it proof?

Dropped it. It still looks new. Sat on it. Yeah, it is really hard. Snow proofness and waterproofness will be for the next report. I will say that the gasket (O-ring) in the housing that holds the lens is quite thin. I have made it a point to be sure to remove the lenses housing only when the light is pointed straight downward to avoid the lens and gasket from falling out. I doubt I will be able to find that O-ring in the grass or dirt at night.

7. How do the colored lenses perform?

The blue lens is almost as bright as the clear lens. The green lens is next brightest and then the red lens. I took some pictures with the Genesis held at my head as in the pictures above, but then with the beam pointed down at my left foot. I'm standing on gravel in our driveway to take these images. This clearly shows the illumination and coloring for each lens. As before the camera was set at 1/3 second and f2.5 and all distances were the same.
Genesis Blue Lens
Genesis Blue Lens
Genesis Clear Lens
Genesis Clear Lens
Genesis Green Lens
Genesis Green Lens
Genesis Red Lens
Genesis Red Lens

8. How useful are the attachments?

Well, as I said in the Initial Report, I do not have a reliable way to carry the accessory colored lenses and the accessory rings. I keep the lenses in the little plastic bag they came in and I stuffed the accessory rings in the belt case, but I need to find something safer that offers more protection and keeps me from dropping the lenses and the accessory rings and losing them.

The Genesis is a flashlight in form and function. There is no stand to make it a lantern. It's not a convertible and has no idea how to be a lantern other then by hanging from its accessory hanging loop ring. If I want to carry the Genesis clipped to my belt then use it later as a hanging lantern, I would need to unscrew the belt clip ring, store it away somewhere, and screw on the accessory ring that has the hanging loop (or key chain loop).

The belt clip operates well, but I would prefer a little more tension so it gripped tighter. I am concerned that the Genesis would be unknowingly pulled off my belt. So I keep it in my pocket and fortunately it's small enough to do so.

After testing, I do not see myself using the fabric holster. The Genesis fits too tightly and two hands are required to remove it from the holster. If it had a pocket to hold the colored lenses and the accessory ring with the loop for hanging, then I would be happy to put it into service. But so far, it does not appear to meet my needs.


Amazing! How do they get all that light packed into that little package? I can only imagine that we'll be lighting up football fields with lights half this size in ten years. The technology of LED lighting is moving ahead quickly and this is an example of an excellent rugged, professional product. The lighting engineers did a great job, but the product marketing folks need to do a little more homework in the field and get out there and actually USE their product for a few months. Give me a way to hold and work with the accessories provided and I'll be a really happy camper. With more testing to do yet, I'll still be having fun though.

Please see below the results of my final two months of testing..



During the final testing phase the Genesis was used almost every day while walking the ranch here in Colorado as well as on hikes at night, including a 3 mi (5 km) snowshoe trek at about 9,200 ft (2,800 m) above sea level (all of this was at night - otherwise it wouldn't be worth mentioning when testing a flashlight).


I have used the same set of Sanyo CR123A batteries that came with the unit. They still project a useable light about 15 ft (5 m) to 20 ft (6 m) down the trail. In fact, I was just outside a few minutes before I started writing this part of the report. Since keeping exact track of time used is difficult in the field, my estimate is that the light has been on for well over 15 hours. I have seen no sharp decrease in light output. I can see the light getting less bright over time, but I saw no sharp decrease, just a gradual decrease and the decline was not noticeable until usage passed 10 hours or so.

I like the push button on/off switch on the back of the unit because it enables me to use the light momentarily to save on battery life. When walking down a moonlit trail or searching for items in the tent I can just push the button to turn the light on for a few seconds and lift my thumb off to turn it off. My dog has learned to like it on his night walks, too. I flash the light each time he barks and he thinks he's turning the light on by barking so he keeps right at it. Kinda funny.

I have new CR123A batteries that I bought on line. Yes, they are available at most local stores, but I purchased brand new 3 volt 1300 mAh batteries for $0.92 US each. I was going to order a CR123 charger and a few rechargeables, but after doing some searching, I have not seen anything costing under $28 US for a good smart charger (that won't overcharge the batteries) and two rechargeable CR123 batteries that are 650 mAH. If I can purchase 1300 mAh batteries for $1 US each that will last for 15 hours or more, I think I'll use the disposable ones for the simplicity. It's not a "green" solution and maybe I'll change that opinion as I get more devices that use CR123 in my gear closet.

"mAh" is milliamp hours, by the way. A higher mAh rating means a fully-charged battery can power a device that consumes more power for a longer amount of time before becoming depleted and needing to be re-charged. For example, a battery rated at 1500 mAh can power a device drawing 100 milliamps for 15 hours, or a device drawing 150 milliamps for 10 hours. The Sanyo CR123A batteries that come with the Genesis are rated at 1400 mAh. So buying rechargeable CR123 batteries that only have 600 mAh capacity would reduce the LED on time to less than half. I would need to have more than 3 sets of rechargeables to rotate them through to cover the same amount of time as the disposables. At least that's how I see it right now.

This flashlight uses 3.0 volt CR123A batteries. There are 3.6 volt CR123 batteries available and I will have to check with Princeton Tec before using 3.6 volt batteries. I almost ordered the 3.6 volt batteries by mistake.

I have not had any issues with the rear battery compartment O-ring coming off or breaking. The O-ring is really thin and it was a concern I had. However, I only removed the accessory ring a few times. Each time the accessory ring is removed it stresses the O-ring because it needs to pass over it. The O-ring stays in place well when just removing the battery compartment cover.

I've dropped the unit in snow and took it from the warmth of my pocket out into 1 F (-17 C) temperatures with no issues and no fogging over of the lens. I've also dropped it on bedrock and was amazed that it kept right on working. I have dropped many flashlights in the same manner and the bulbs would pop and not work. The metal finish on the Genesis is like new. The rubber center moldings have slight markings probably made by fingernails or when hitting the ground when dropped or from being clipped on my belt.

I have to admit that I still can't figure out how to easily and safely carry the colored lenses around without scratching them up or losing them. In most cases I would only want to bring one lens anyway (the red one). There was one night in a tent when I unscrewed the front lens holder and the clear lens fell off and rolled around and went under my legs somewhere. Good thing the Genesis still works with the lens holder off, because I needed the light to find the clear lens. Now I know the lens is not locked in place and can fall off as soon as the lens cover is removed.


In all, this is a really neat flashlight. At 45 lumens brightness, this thing lights up hillsides (we call them hogbacks here in Colorado) several hundred yards/meters away with fully charged batteries. The batteries can last a long time, (up to 20 hours of light using 1400 mAh batteries) and the current control circuits provide constant light for a longer period as battery voltage is depleted, although the light will still get dimmer as the battery loses voltage. It's pretty hefty. It floats like a rock, but has waterproof integrity down to 3 ft (1 m) for up to 30 minutes. It is durable. It'll be in my pack for a long time.

Thank you to and Princeton Tec for the opportunity to test this neat light.

John R. Waters

This report was created with the Report Writer Version 1. Copyright 2009. All rights reserved.

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