Reviews > Lighting > Headlamps - LED > Princeton Tec Corona > David Sowards-Emmerd > Initial Report

Initial Report - Princeton Tec Corona
August 23, 2004

Backpacking Background:
I began backpacking semi-frequently about four years ago, soon after moving to California. I generally take weekend (1 night) trips, and occasionally take 3-4 day trips. Most of my backpacking experience is at moderate altitude, 6,000'-12,000' (1,800-3,650 m), in conditions ranging from dry desert to hail/heavy snow in the mountains. In winter and spring I split time between Southern California (SoCal) deserts and snowshoeing/skiing/snowcamping in the Sierra/Cascades. Summer and fall I tend to stick to the high country. I have reduced my packweight down to less than 50 lb (23 kg) over the past year - including food/water and a bear barrel. I'm trying to include more mountaineering, climbing and bouldering in my trips.

The product was received on August 17, 2004.

Product Description:

Manufacturer's Description:

''Undoubtedly in a class by itself, the new Corona Headlamp is the brightest and most efficient area light on the market. Eight super bright white, shock resistant, virtually unbreakable wide angle LED's are the foundation of the Corona, allowing the user to switch between 8, 5, 3 or 1 LED use - making it a great hands free lighting choice to satisfy all of your outdoor, work and personal lighting needs. The multiple modes and functions allow this headlamp to perform every task needed around camp and trail, from flooding your entire camp site in bright light or powering down for more up close tasks, like reading in your tent. An innovative circuit system allows the user to fine-tune and adjust to the desired brightness level on each of the 4 LED output modes, while offering maximum constant light output for the life of the installed batteries. The result: a very bright flood/area light that offers excellent peripheral light, allowing the eyes to work with ease in a localized area- there are no dark spots in the user's vision, neither forward nor side to side. For the perfect fit, a durable nylon head strap provides plenty of adjustment, and the head assembly pivots to allow you to shine light where you need it. Top it off with 10,000 hours of bulb life, emergency / flashing signal modes and you've got one totally cool headlamp.''

Manufacturer's Specifications:
Weight (w/ 3 AA Alkaline batteries): 227 g / 8 oz

Specifications (as measured by tester):
Weight (w/ 3 AA Alkaline batteries):231 g / 8.15 oz
Weight (w/o batteries):158 g / 5.57 oz
Color: Yellowish green

Product Description and Basic Operation:

The Corona packaging contained one Corona, 3 AA alkaline batteries, an instruction manual, a small blue note regarding avalanche beacons, and resealable plastic packaging (read: you try it out in the store and nobody would ever know!)

The LED module consists of 8 LEDs arranged in three rows, with 3, 4, and 1 LED in each row from top to bottom (see photo). Two buttons are used to turn on the Corona and select the mode. The larger button on the right (if the corona is on your head) turns on all 8 LEDs on the first click, and further clicks cycle through three more modes: 5 LEDs, 3 LEDs and 1 LED. If more than 5 seconds passes between clicks of the this button, then clicking turns off the Corona. The left button (smaller, with a central protruding bump to help distinguish the buttons in the dark) selects between 3 modes: bright (which is the default when the Corona is first turned on), dimmer, and bright strobe, which blinks not quite twice every second. Both of these buttons are cyclic, so the last mode cycles back to the first mode (e.g. bright strobe to bright) with an additional click of the button. However, for the right button, the cycle is 8, 5, 3, 1, off, 8...

Behind the LEDs (on the back side of the LED module), a metal heat sink is clearly visible (see photo). A plastic shield prevents touching the actual heat sink because it can reach temperatures as high as 170 F / 77 C.

Directly below the heat sink is the pivoting mount that connects the LED module to the headband. In addition to the standard one-piece headband, an over-the-top strap is included (see photo). Both straps can be completely removed from the LED module and battery pack without cutting or modifying the Corona.

A wire, 13''/ 33 cm long, that connects the battery pack to LED module runs along the right side of the headband, through two plastic wire guides. The wire is just long enough that when the LED module is worn on the headband, and the battery pack is removed, I can put the battery pack on a pack shoulder strap (the very top of it).

The battery pack is hinged along the longer side and opens like a clam shell. A plastic tab snaps down to securely close the battery pack. A rubber seal is obvious inside to keep those batteries dry. Additionally, a small stopper (see photo) prevents pulling the wire right out of the battery pack.

Various burn times are discussed on the packaging and inside the instructions. These claim the Corona is nearly twice as efficient on the low power setting compared to the high power setting due to the current regulation ( I believe it's only really regulated on the low power setting). The instructions also includes a brief discussion about the effects of current regulation. Basically the circuits will try to maintain constant brightness in the LEDs as long as possible (5-30 min with alkaline batteries and 8 LEDs on high power). After this constant brightness, the light will slowly dim as the batteries drain. At some point the low power setting will be just as bright as the high power setting (for the same number of LEDs) and then you know it's time to start thinking about backup batteries: it means the batteries are only able to supply about one quarter of their original power. From the packaging, the approximate run times to 1/2 lumen (approximately 1/40th watt halogen equivalent) are:

	# Hours	on:
# LEDs	High	Low
8	30	36
5	38	45
3	46	55
1	55	70

Which means you'll still have plenty of time left on the batteries, but the maximum light output will be lowered considerably.

Note on batteries (from the instruction booklet): ''The Corona is designed to use three AA alkaline or lithium batteries. Rechargeable NiCad or NiMH AA cells will not harm your light, but may not provide sufficient voltage to allow maximum brightness''

Warning:

A warning about using the Corona in conjunction with an avalanche beacon was included in the packaging. This suggests that the Corona circuitry may interfere with a beacon in receive mode when the Corona is on one of the brighter settings. Therefore this light is not a wise choice for search and rescue operations in avalanche terrain.

Test Plan:

Testing Locations:

Almost all the testing will take place in California, in conditions ranging from cold snowstorms and rainy bike commutes to the standard peaceful night around camp. Most of the use will probably be around camp at night, and along with some night hiking and caving. I will also use it as a supplemental light on my bike commute, more to be seen than to light my path. I'll be using NiMH rechargeable batteries almost exclusively during the testing period (unless the manufacturer offers to supply more alkaline or Lithium batteries!)

Specific things to test:

• What brightness settings and LED configurations are most useful under various conditions? I'll try to pay more attention to selecting the correct mode for the circumstances but I believe the dim/8 LED and dim/1 LED will be the most frequently used. I will compare beam shape and brightness to a handful of other lights I own with a digital camera. Additionally, I'll compare the Corona's beam in each of the four LED configurations. Additionally, I'll try to measure the difference in brightness between using fresh alkaline batteries and using just-charged NiMH rechargeables. Also, I'll try running it down for 30 hours and high power for a comparison photo of 1/2 lumen.
• Does the power regulation shut off the light before the batteries are actually dead? For alkaline/Lithium batteries I would want to get every last drop of power out of the batteries. But for rechargeables, this damages the batteries. I will try and check the voltage of the cells immediately after the batteries 'burn out'.
• I'll try to think of some real uses for the strobe mode (aside from a rescue signal or just trying to be annoying)? This is probably most useful for my bike commute when the Corona isn't the primary light source.
• Is it easy to attach a colored (red say) piece of cellophane or some other form of filter over the leds?
• How hot does it get hot during use and is the reduced light output (to avoid overheating the LEDs) noticeable? This should be pretty easy to determine with a hair dryer and the Corona set on full power.
• In cold weather, can I fit a hat/balaclava/headband over the battery pack, or is it just too bit big?
• Is the headband comfortable? Is the top strap really needed for basic chores around camp or night hiking? How comfortable is the battery pack when I lean my head back on it (e.g. reading).
• Does the headband fit on my climbing helmet? Is it stable?
• The Corona is claimed to be water resistant. I'll test this out bike commuting to work in the rain, probably during the Long Term Report testing phase.
• How durable is the Corona? The few obvious points of failure are the wire connecting the battery pack to the LED module and the pivot point connecting the LED module to the headband. Is the plastic much more fragile in the cold - I don't intend to test this but I can't rule out accidentally dropping the Corona or falling when skiing at night.
• Finally, I'll do a little research on the power regulation scheme for the Long Term Report.

Suggestions for improvements:

• Add 6-12'' / 15-30 cm or so to the wire connecting the battery pack to the LED module. This excess could be looped through the guides, or simply wrapped around the battery pack, but would allow the battery pack to be put inside clothing (shirt pocket) for cold weather use since the battery pack is completely removeable from the headband under the current design. An extension cord with quality connectors would be even better!
• Change the default brightness setting to dim. Since this setting is the most efficient and people tend to be lazy (just turning it on instead of cycling through modes) - especially with gloves on in the cold, when battery life will be most important.

Reviews > Lighting > Headlamps - LED > Princeton Tec Corona > David Sowards-Emmerd > Initial Report