The JetLites F-U2 is the successor to the JetLites F-1 introduced late last year. In a field of exciting but crowded self-contained bike lights, the scientists at JetLites managed to come up with a light that is truly high end like Lupine and Exposure but is affordable at $179.
The most dramatic part of this light is the case. It’s a machined aluminum case that showcases the best American construction available with a sleek, curved body that hosts plenty of cooling fins. The top of the light screws off to expose the lens and electronics. The back screws off to access the battery. Threading on these parts is very fine to maximize heat transfer from the LED to the case of the light. This not only helps the LED operate at max power, it also helps the battery operate at good capacity in frigid conditions. We hear that lithium cells can lose as much as 50% of their run time when operating in very cold conditions. We ran this light at full power, static on our test bench with no air moving around it. Normally we avoid this and always run a fan but wanted to test the heat dissipation abilities of this light. After 20 minutes, the whole light was warm all the way to the switch at the back. The temperature was pretty even throughout the light and there was no flickering or stepping down of the light at all. It is not possible to do this with lights with separate batteries since there’s not enough heatsinking. And most other self-contained lights get very hot just near the LED.
The LED is the awesome Cree XM-L with excellent binning chosen by JetLites (quality batch of LED). And the battery is a Panasonic 3100 mah 18650 cell which is one of the best available today.
Run time is stated at 1.7 hours at full power. Although it seems short, that run time doubles at medium power. It is better than the competition which mostly run 1.5 hours. Most importantly, the rider can carry an extra battery and quickly replace the cell during a ride to get another full battery run.
The switch is nice and big at the end of the unit and it is easy to operate. It is in a recessed cavity so the battery can be stood up on its end and used as a lamp. A plastic diffuser on the lens would make this an even better light source or light saber.
- Price: $179
- Claimed Lumens: 850 Lumens
- Measured Lumens: 675 Lumens
- Measured MTBR Lux: 74 Lux
- Light Head Weight: 169 grams
- Installed Weight: 195 grams
- Run Time: 1:40 Hours
- Category: Flashlight
- Impressive construction
- Very good cooling with heatsinking, and heat transmission from the LED throughout the case
- Beam pattern has a big halo with a very bright hotspot
- Run time is better than most self-contained lights
- Good value at $179
- Battery is field replaceable
- Helmet mount is secure, well-made and detaches on a crash
- Dual action switch is convenient
- Good run time for this amount of light
- No USB charging and battery has to be removed to be charged
- Center spot of beam pattern could be a little bigger
- Not a big improvement over last year’s F-1
Mounting is done with the classic JetLites helmet mount included in the kit. This mount straps on the the helmet and the light can be aimed up and down once installed. This features the safety mechanisms of Jet where the light can pop off in the event of a heavy impact to protect the rider’s neck from twisting.
The light can be mounted with the robust handlebar center-mounts from Jet. These mounts are extremely high quality and place the light right over the stem.
MTBR Light Meter Measurements: Compare all lights here.
This light measured 74 Lux on our ambient light measurement facility.
Integrating Sphere Measured Lumens: Compare all lights here.
675 measured Lumens. Claimed Lumens by the manufacturer is 850 Lumens. The Lumen-hour graph below shows how the light performs over the first three minutes of its battery cycle.
Backyard Beam Pattern Photo: Compare all lights here.
We photographed the lights in the same location setting with the same camera settings. The photos were taken in the back yard that is approximately 25 yards long. These photos feature many objects and a distinct background to analyze detail and beam pattern.
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