Headlamp Design with Blade attachment used on many helmets.
Dual 3 Watt LED
4 Brightness Levels all Fully Regulated
Hall Effect Switch Assembly (magnetic)
Runs on 6V to 18V
Water tight to 25 feet
One of the best things about the Stenlight is how small it is.
The light itself is about the size of a film canister, or alittle
smaller than a D size battery.
This makes it very easy to use for one of its main purposes, caving.
You can hardly tell the Stenlight is on your helmet at all,
and the small size keeps you from bumping it into cave walls.
The body of the Stenlight is precision machined aluminum,
with a stainless steel front face
place to hold the lens in place.
The blade attachment, hinge, and switch are also all stainless steel.
The dual 3 Watt LEDs can produce up to 140 lumens of light.
That is a very impressive amount of light output for a light of this
It can compete with any other incandescent headlamp I have seen,
and flat out kills most of them. Only HID systems can out perform it.
The light met everyone of my expectations, and exceeded many of them.
Design and build quality were excellent, its size and input voltage
range makes it very versatile.
As stated above, the Stenlight is smaller than a D cell battery.
With the blade attachment and hinge protruding out the back about 7/8"
The Stenlight weighs under 125 grams, minus battery pack.
This is important for a headlamp, you dont notice the weight much at
The 2 cell Lithium Ion battery pack balances it well, when mounted on
the rear of the helmet.
The Stenlight is a very well made light.
All the materials used are high grade and suit its needs well.
The body of the light is aluminum, all other external parts are
Some of the stainless steel parts had some machining marks, from being
stamped and bent.
Resulting in some rough edges, but nothing out of the ordinary for that
type of process,
and nothing that could cut you while handling it.
Overall, everything on the Stenlight is meant to be very rugged, and
survive very extreme conditions.
4 Fully Regulated Brightness Levels - Low, Medium, High, and Turbo
The testing I have done so far, shows the Stenlight to be very
Maintaining a rock solid, very flat output for its entire runtime. There
is no dimming over time.
This can be seen in the runtime test below, using the "High" setting.
These 4 Brightness Levels are controlled with a magnetic Hall Effect
There is a tiny magnet attached to the rotating switch, a sensor inside
the light monitors the magnets position,
and changes the brightness level accordingly.
No part of the switch actually penetrates the inside of the Stenlights
The result is that the switch does not effect the lights water
resistance what so ever.
This also makes the switch very reliable, because there are no internal
The only moving part of the switch is its actual rotation, which is
assisted by a ball bearing.
The stainless steel switch, connected to the back of the light, rotates
a full 180 degrees.
Making is very easy to operate with thick muddy gloves on.
This also makes it very easy to reach up, and feel what setting you are
The Stenlights circuitry has built in thermal protection,
that prevents both the LEDs from running too hot, and to keep the body
of the light cool enough not to burn you.
In most conditions, the Stenlight will only thermal limit itself when
used on the Turbo setting for long periods of time.
Once the circuit detects that the LEDs temperature is getting above a
safe level, it will reduce
the Turbos output by about half. Or, about 140 lumens, to about 70
lumens when thermal limited.
User Replaceable Optics
The Stenlight comes with one 15 degree, and one 5 degree optic
There are a variety of different optics
out there, but be aware that not all of them will fit properly.
The supplied optics are by L2Optics. Most all of those should fit,
except the rectangle beam pattern type.
I replaced the 15 degree L2Optics optic in mine, with a 25 degree optic
These were slightly short than the stock optics, and needed shimmed into
so that they sat high enough in the optic holder to engage the front
lens, which is what holds the optics in place.
Also, make sure the the optics you use are not too tall, this can cause
the lens to crack when tightening.
I also tried using IMS 17mm Reflectors, they are a couple mm too tall,
and will not work with the Stenlight.
6V to 18V Input
For now, the stock battery pack for the Stenlight is a 2 cell 7.2V
Lithium Ion 2300 mAh Pack.
Which will get you about 7 hours of runtime on High.
That is a very respectable runtime, considering its output is bright and
completely flat regulated.
The wide voltage range makes it very versatile for many situations.
You can make your own battery packs to fit many needs.
Just think of running it off a car battery for DAYS ! :)
Output is rated at:
3 Lumens on Low
12 Lumens on Medium
45 Lumens on High
140 Lumens on Turbo (70 when Thermal Limited)
I have a photo below that
I made using different combinations of optic.
The beam pattern will vary greatly, depending on the optics used.
I found the stock beam with 15 and 5 degree optics alittle too narrow.
I personally like a wide flood for headlamps, thats why I swapped the 15
degree optic to a 25 degree one.
Runtimes are rated as follows, with 2 Cell 7.2V 2300 mAh Battery Pack:
> 3 days on Low
> 24 Hours on Medium
~ 7 Hours on High
~ 3 to 5 Hours on Turbo (Thermal Limited)
~ 2 Hours on Turbo
Below is a runtime I made, using a battery
pack I made.
The pack is essentially the same as the stock Stenlight pack.
It was charged with a Triton multi-purpose charger. The stock Stenlight
the pack to a slightly higher voltage. This would explain my runtime of
slightly under the rated 7 hours.
As you can see, the runtime is VERY flat,
due the the circuits regulation.
This means that you get the full potential of the battery's power.
There is no more changing batteries because your light is half as bright
as it was with fresh batteries,
you end up wasting battery power that is left in the cells.
The Stenlight has complete thermal protection built in.
The circuit monitors both the LED and body temperature, if either raise
above a safe level,
the current to the LEDs is then limited, letting the light cool down.
Under most circumstances, thermal limiting only occurs on the Turbo
On High, the body of the Stenlight can get quite warm, but it is still
within a safe temperature,
and can be touched with bare skin.
There is not alot of mass to dissipate the heat, due to the lights small
But the body of the Stenlight is rather thick, and there is alot of
aluminum there for its size.
I see No problem with leaving this light on, unattended, on any setting.
Very Small and Compact
Very well made, and able to withstand rugged conditions
Very bright, especially for its size
Hall Effect Switch
Switch's long travel makes it easy to operate with gloves
Wide Voltage Range
4 Fully Regulated Brightness Levels
Blade attachment not common to none helmet users. (there are plans
for bike and headstrap mounts)
Not compatible with common batteries. (there are plans for AA
The Stenlight is simply the best headlamp/caving light that I have ever
came in contact with.
I love the size and shape of the light, you can hardly tell its on your
The long travel on the
switch is great, no more fiddling with small buttons. Its also very easy
to tell what
brightness level you are on, by simply reaching up and felling where the
There is 1/2" travel between each level.
After about a 4 hour day
of caving, I noticed that I had gotten a large amount of dirt and mud in
I was a bit concerned at first, due to the switch having a very gritty
feeling, as I rotated it.
Fortunately, the light never failed to work, and all levels were working
This was easily fixed my submerging the light in water, and rotating the
switch back and forth a few times.
The Blade attachment method is used mainly
for helmets, and has been used by cavers for a long time.
But it may not be very useful to some users that dont use helmets.
There are plans however for regular headlamp straps, and bicycle mounts.
The Prolite headstrap is said to work though, and I have one on order to
The Prolite strap item 17-2402,
along with the Stenlight, can be purchased at Inner Mountain Outfitters.
The Stenlight is a bit pricey, especially
after buying a battery and charger.
But I have found the old saying is always true, You get what you Pay
I am confidant that the Stenlight will provide me with many years of
trouble free operation.
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