It is always a problem to find a headlamp for Adventure Racing; it must provide enough light that you may cycle freely and push forward in the night at unknown bushes, it must be waterproof enough that you may bathe in a lake or drown it in a kayak. Spark seems to meet most of these requirements...
Some marketing data.
The first head lamp based on the Cree XM-L bin T5 Neutral White led. A twin version is ST6-500CW based on the T6 bin led - more efficient (500 lumens instead of 460), but in Cold White tint.
Super:460 lumens/1,4 hour
Max:300 lumens /2,5 hours
Med1:140 lumens /8 hours
Med2:45 lumens /28 hours
Low:8 lumens /8 days !
Power supply : One 18650 rechargeable Li battery with range from 3.7V to 4.2V or 2*CR123. Reverse polarity accepted circuit
Waterproof : IPX 8 (that means that it should withstand 48 hours in the rain and drizzle ;-).
Weight : without battery: 50g / with battery and headband: 150g
Dimension : 78x52mm
Price : 100$ + 23$ for shipment
Manufacturer www : http://www.spark001.com
Precisely made, nicely packaged, the kit includes spare sealing o-rings and spare glass lens enabling to change the light beam into a diffused one. To use a full capabilities of it you need only 4 18650 cells, a container for them and a charger - you have to add extra 30-40 dollars for that, what increases the total cost of the whole kit up to ca. 170$. It is not cheap, but at least the light is suitable for everything, at least, in theory. Only the weight of the kit is in a disagreement: the headlamp itself weighs 76g instead of 50g declared, what after adding the 18650 cell and the strap, gives the total kit weight of 167,5g.
What does squeak inside ?
The light source is the newest high power led on the market Cree XM-L. In this lamp the manufacturer use T5 (260 lumens for 700mA current – for those less acquainted with leds: this is ca. 2W for Cree XM-L). The color selection is Neutral White, i.e. ca. 4500K what enables to render the color and surface quality of the objects being illuminated rather well. Within the scope admitted by the manufacturer, the lamp may be disassembled without any problem:
The user may, without any problem, make a self dependent replacement of the emitter but there is no room for other play, since any other trials to take the lamp into pieces end, in 99% cases, in a damage of the supply wires at the driver.
Power supply and control.
For the use during competition, the best solution seem to be the 4 18650 rechargeable cells + 2 waterproof package and you will have an energy reserve for 48 hour event (assuming 8 hours of cycling in the max 300 lumen mode and 8 hours of roaming in the Mid2, 140 lumen mode).
What gives you a protection against reverse polarization? It is this, that if a little fuddled User puts the cell upside down, the lamp will operate as she or he has put it normally - the polarization makes no difference for Spark ;)..
The lamp switches on in the minimum mode; to change over to a higher mode, you have to keep the button depressed - the controller stores the last set mode even after the cell is taken out; since it operates in the loop, you have to go through max in order to return from mid2 to minimum.
Declarations of the manufacturer's does not often match the reality - here they are pretty close :)
Only the result for the boost mode is a little disappointing, instead of the declared 460 lumens the output is only 400, and after the lamp warms up it drops to about 380 - well, not everything is perfect :(. Fortunately, other modes keep the margin of error arising from the use of a different components in the construction of the driver..
Hoe does it light ?
It lights very nice since it has one of the most powerful leds on the market on board - a small OP reflector, in connection with the Cree XM-L led, does not enable to gain a high focus but, when the lamp emits 300 or 400 lumens, the result is very satisfactory :). The light distribution is very similar to that liked by many runner, that of the Silva 478 reflector - the only difference is that the lamp is several times smaller and the batteries last for much longer. Second pair of photos is taken after replacement of the glass by a mat one; it serves here for a diffuser; the photos for the other modes are in a photo comparison test..
Spark ST6-460NW – Boost (declared 460 lumens for 5 minutes).
Spark ST6-460NW - High (declared 300 lumens for 2,5 hours).
And now, something for a comparison :)
Fenix HP-11 – High (declared 277 lumens).
Silva 478 – 20W halogen about 400 lumens.
As you can see, Spark prevails over both the newest (Fenix HP-11) and the oldest (Silva 478 halogen) competition; now, the availability, price and needs evaluation remains only. The complete kit does not belong to the cheapest ones but it makes it possible to apply one light in all sport disciplines, providing the satisfactory amount and good distribution of light. Now, there is only one but: the applied holder made from soft rubber, in connection with the strap, is comfortable but it results in that, during running, is bumping a bit, and not all Users may be happy about that.