Spark SX5-NW: $75.00
Above: USB Charging from SX5 battery pack with optional USB adapter.
Sometimes referred to as the 'kitchen sink' model. It has a wired battery pack at the back of the headband that uses 3xAA or 3xAAA, or 26650 cell, and, with the optional battery pack the ability to use 4x18650 or 8xCR123 (you can actually shim a 18650 or 2 RCR123A cells into the headband holder as well, see Headlamp Accessories for the shim). The use of the 18650 Li-Ion batteries results in the lighest possible configuration for your power supply in terms of weight for the amp capacity you carry. Running 4x18650 in the optional battery pack results in the ability to run at 320 lumens for up to 11.5 hours (if you were using AA cells you would get 2 hours at 320 lumens and 4 hours at 180 lumens), and more than a year on low with only 140g on your head! Spark is know to be conservative relative to the other brands with official beam throw distances for spot. They rate this lamp at 100 meters, but as you'll see in the beamshot slideshow, while using a neutral white wavelength, it significantly outhrows the Princeton Tech Apex which claims to have the same distance and uses a wavelength that does not render colors naturally.
The 18650 battery pack also has some interesting possibilities for a frankenstein mod that would permit the user to charge their smartphone based GPS or other USB powered devices when in the backcountry.
For full specifications grab the user manual here.
* NiMh batteries weigh more than Lithium for the same amount of energy. For example, the best NiMh get up near ~90Wh/kg range of energy density, whereas Lithium can achieve ~150Wh/kg. However packaging materials can result in a larger overall weight difference. For example a GP 2700mah rechargable NiMh cell weighs 30g as opposed to an Energizer Lithium AA cell's 14.5g. When you also factor in that the NiMh self discharge rate can be as high as 20% on the first day, that 2700mAh cell becomes a 2200mAh cell as opposed to the lithium AA at approx 3000-3400 mAh (energizers yield about 3000mAh when discharged at 1amp and 3400 when discharged at .5amp). Both Lithium and NiMh have good cold weather characteristics.
Ratings for Li Ion, (The runtime specifications vary when diffirent batteries are used).
In testing we got 55 min of runtime using 1 AA LiFePO4 cell on Max., and 3 hrs 50min with 3 Recyko cells. 3 LiFePO4 AA cells with 2 dummies is 84g, the 3 Recyko weigh 86g.
Best use scenario...
Evident advantages as a work light. Good for multi day backcountry trips where the light will be used nightly for everything from travel to personal ambient lighting in hut or camp. We say 'personal' because it does not have the flexibility afforded by the SD series adaptors to set it up on your camera tripod or clip to a metal surface (but you could always take along another SD52 or SD73 as well for that). The optional battery pack has interesting possibilities as a power pack for driving or charging other devices.
Now for a comparison with the closest light you may find hanging on the rack at MEC, the Princeton Tech Apex. It weighs in at 300g and gives you 200 lumens of output for 1.5hrs illuminating the track 100m in front of you. The SX5 gives the same range with a variety of battery choices, weighs in at 274g with 3 aa cells, but gives you more light at 320 lumens for 2 hours, plus it costs $10.00 less, uses one less AA cell, and does not have plastic hinges to break on you.
One criticism of these types of light concerns the cable that brings power from the external battery pack. The Princeton Tech cable connections fray and crack after about a year, and the cable itself can become entangled in some circumstances such as bushwacking. The SX5 has not been around long enough for a true longevity test on the cable, so only time will tell us how it's going to stand up in the long haul.