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Black Diamond Cosmo Review



  • Currently 3.0/5
Overall avg rating 3.0 of 5 based on 1 review. Most recent review: January 11, 2014
Street Price:   $30 | Compare prices at 6 resellers
Pros:  Lightweight, small size, great price, incredible battery life
Cons:  Much less brightness than alternatives
Best Uses:  Applications where battery life is essential
User Rating:       (0.0 of 5) based on 0 reviews
Manufacturer:   Black Diamond
Review by: RJ Spurrier ⋅ Senior Review Editor, OutdoorGearLab ⋅ January 11, 2014  
While this is a good headlamp, we implore you to spend another $10 and get the Black Diamond Spot which has much better beam brightness and quality combined with a very respectable battery life. The Cosmo is a middle of the road kind of light. It is average performance and average battery life at an average price. If you are on a budget, look to the Energizer 3 LED which scored just a little lower for a fraction of the price. Or if you're looking for a lighting powerhouse, check out the Coast HL7.

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  • Photos
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OutdoorGearLab Editors' Hands-on Review

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Spot mode
Credit: Shellay Glatz

Performance Comparison

Trail Finding

A score of 7 is very respectable, especially for a $30 headlamp. But if you spend just another $6, you get a trail finding powerhouse with the Coast HL7. As you can see in the beam comparison below, the coast shines much further.

Beam Distance Photos

Black Diamond CosmoCoast HL7

It's not the most apple to apples comparison, because the Coast gets that awesome beam throw by burning through batteries very fast. Perhaps a better comparison is with the Cosmo's big sibling, the Black Diamond Spot which has a solid battery life.

Beam Distance Photos

Black Diamond Cosmo

Close Proximity

This is where you see the big difference between the Spot and Cosmo. The Spot, in close proximity mode, casts a very even beam. The Cosmo has a hot spot in the middle and not very even light.

Close-proximity Beam Pattern

Black Diamond Cosmo

Battery Life

This is where the Cosmo stands out, a little. It lasts for 14 hours in our ANSI measured high mode runtime tests. This is much better than the Spot (5.2 hours), Coast (3.3 hours), and Icon (8 hours). But during that test, the beam power starts much lower on the Cosmo which does not make it the best apples to apples comparison. Confused? What is ANSI? See our detailed description in the Headlamp Review. We did not measure low mode runtime, but the Cosmo's claimed 250 hours is one of the highest of any headlamp in the review.


This light casts a beam 45 meters in our measured max beam distance tests. This compares with 70 m for the spot and 128 m for the Coast. 45 m is not bad, it's just not that impressive for a $30 headlamp when the Coast goes three times as far for an extra $6.


At 90 grams, this is a compact but not ultralight headlamp. It is about the same weight as the Spot. For comparison, the featherweight champion Petzl e+LITE is less than a third the way at 26 g.


The thirty dollar price point is a tough spot. Just a little more gets you the top scoring headlamps in our review. And for $12, you can get a headlamp that scores just a little lower.


This is a solid light but there are just too many competitors that either score much better for another $6-10 or just a little lower for much less money. The Black Diamond Spot gives a lot more performance for only $10. It has a nearly identical form factor with a much better beam. The Coast HL7 is a light-emitting powerhouse for only $6 more. And for a mere $12, the Energizer 3 LED scored just two points behind the Cosmo.

RJ Spurrier and Chris McNamara

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OutdoorGearLab Member Reviews

Most recent review: January 11, 2014
Summary of All Ratings

OutdoorGearLab Editors' Rating:   
  • 1
  • 2
  • 3
  • 4
  • 5
Average Customer Rating:     (0.0)
Rating Distribution
1 Total Ratings
5 star: 0%  (0)
4 star: 0%  (0)
3 star: 100%  (1)
2 star: 0%  (0)
1 star: 0%  (0)

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Black Diamond Cosmo
Credit: Black Diamond
Where's the Best Price?
Seller Price
Backcountry $29.95
REI $29.95
Amazon $29.95
Compare prices at 6 sellers >

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