One-Year Review: Princeton Tec EOS Light

I’m a huge proponent of helmet-mounted lights.  You might even say that I’m a bit obsessed with them, as I own a couple of expensive, high-powered setups.  But over the past year, my helmet light of choice has been the sub-$50 Princeton Tec EOS.

For most commuters and utility cyclists, weight isn’t too much of an issue when it comes to selecting bicycle lights.  Sure, some systems weigh a little more than others, but once you mount them on your bike, the differences become a lot less noticeable. That changes, however, when the light is mounted to your helmet.  Adding weight to a bicycle helmet can increase neck, and even shoulder fatigue.  This became apparent to me when my neck and shoulders would be sore the day after a lengthy night ride.  That all changed, though, when I switched over to the EOS.  With the three included AAA batteries, the Princeton Tec tipped the scales at a measly 105 grams.  To put things into perspective, the battery packs alone on my other systems range between 115 and 150 grams .

Over the past couple of years, Princeton Tec has made improvements to the EOS, and the current version produces an output of 70 lumens.  While some may consider that number low, remember that there’s more to a light’s usefulness and efficacy than just raw numbers.  To put those lumens where they should be, Princeton Tec uses a special collimator (think of it as a “reflector”) to collect and focus the LED’s light rays into something useful.  While that may sound like marketing-speak for, “size doesn’t matter,” I’ve found that the EOS actually puts out more usable light than other (brands’) lights that claim 180% more lumens.

In addition to the helmet mount, Princeton Tec includes handlebar and elastic headband attachments.  Transferring the light between the helmet and handlebar mounts is easy, and doesn’t require removal of the mounts once they’re attached.  The handlebar mount held securely during bumpy, off-road riding, but the mount’s knob interfered with the brake cables on the crowded center section of my commuter’s handlebars.

GRAVELBIKE.com gravel bike princeton tec bike light led

In addition to helmet-mounted duty, I found that the EOS performed particularly well as an auxiliary light when paired with my dynohub-powered main headlight.  The battery-powered Princeton Tec came proved especially handy at stop lights as it maintained full output.  Off-road, the EOS proved invaluable on slow, grinder-type climbs when the dynamo light’s output would drop due to the generator’s low RPMs.

Princeton Tec uses regulator circuitry to maintain the initial brightness as long as the batteries have sufficient voltage.  The manufacturer claims a burn time of 121 unregulated hours on low, with a regulated burn time of 50 hours.  While I didn’t keep records of how many hours I’ve logged on the EOS, I can say that I’m still using the original alkaline batteries with no noticeable reduction in brightness.

Additional information about Princeton Tec’s line of bicycle lights can be found on the company’s website.

3 thoughts on “One-Year Review: Princeton Tec EOS Light

  1. Has the LED been upgraded in the EOS? I have a model from 5 years ago and have been very happy with it as a helmet mounted light but I had never notice any claims of upgraded output. Back when I purchased the light LEDs were still being sold in terms of watts, and the EOS was listed as a 1watt LED iirc. I’ve been looking for a light weight replacement with higher output but haven’t decided on anything yet. If the EOS has been updated I’d be tempted to be a repeat customer.

    • Here’s what the folks at Princeton Tec say:

      “The EOS is definitely brighter and shines further than the version from several years ago. It is actually 3x brighter now. The new EOS Bike is also much better for distance than the Corona Bike. The Corona Bike is a strong flood beam, but lacks the long distance element, where as the EOS Bike provides more of a long distance spot beam.”

What's on your mind?