Koolertron 1x Cree U2 LED Bicycle/Headlight
Reviewer's Overall Rating: ★★★☆☆
Summary:
| Battery: | 4x 18650 Battery Pack (Included) |
| Switch: | Rearward Switch |
| Modes: | 4: High, Medium, Low, and Hidden Strobe |
| Mode Memory: | Always starts on High |
| LED Type: | 1 x XM-L (CW) |
| Lens: | Glass |
| Reflector: | Aluminum - 2 Stage (Light OP and Smooth) |
| Price: | $38.99 Shipped |
| Provided by: | KoolerBuy |
Pros:
Good build quality
- Smooth threads
- Snug fitting O-ring
Decent thermal management.
Functioning as a headlight is surprisingly comfortable.
Cons:
Included Battery Pack (Detailed Later).
Weather resistance (Several areas where dirt and water can potentially be an issue).
Actual lumen output is approximately 550lm before losses.
Mode spacing (Medium is essentially pointless).
Mode cycling required to turn off.
Occasionally when connecting the light to the battery pack the indicator will be red, despite the pack being well above 3.5v.
Price.
Function/UI:
| High | 1.6A |
| Medium | .9A |
| Low | .18A |
Battery voltage indicator led draws 15mA and is constantly on once the connection is made to the battery pack.
The indicator is Green while the battery pack is greater than 3.5v and Red when the battery pack falls below 3.5v
(Mouseover green/red indicator)
Press switch for High.
Cycle to medium with another press of the switch.
Cycle to low with another press.
Turn off with a final press.
On any mode or while the light is off, press and hold to enter strobe.
Press switch again to exit strobe and enter high mode.
Charging:
The battery pack arrived at 3.86v.
Charging of the included 4x 18650 battery pack went as follows:
Initial Charge cycle: 3.86v to the charge adapter shut off at 4.23v: 6 Hours 40 Min.
Second Charge cycle: 3.10v to cutoff at 4.23v: 7 Hours 5 Min.
Measuring the charger's output:
| Charge Current | Battery | Charger LED Indicator |
| 1.3A | 3.10v | Red |
| .300 | 4.07v | Yellow |
| .150 | 4.19v | Green |
Charger reached about 100*F peak temperature, and the battery pack never felt warm to the touch.
Run-time:
Using the included battery pack at 4.23v.
Ambient temp 80*F, indoors, low air movement. 1.6A Drive current on high. Green led indicator.
Reaches peak temperature of 123*F at 40 minutes.
Out of regulation at 55 minutes.
At 120 minutes the battery pack is at 3.6v and drive current is down to 1.1A on high.
At 125 minutes the Red led indicator on the switch is on.
Test Complete at 150 minutes the brightness of high is roughly equivalent of low mode and drive current is .2A. Battery Pack measures 3.10v.
Based on the runtime test I estimate the battery pack generously at 3500mAh or 875mAh per 18650. It is just barely acceptable imo, considering a good set of 4x 18650 cells will easily triple the runtime and will maintain the 1.6A drive current for longer as well.
Pictures:
The light arrived inside a cardboard box and immediately inside that was this box. Just some generic cover.
Inside the box:
Head..strap dealie? (There isn't a better word for this in english; I'm certain.)
Headlight/Bike light
Charger
Converter adapter
2x attachment pieces
Battery pack holder (Battery pack inside)
Couple shots of the light
The machining is quite nice. Annodization is smooth and consistent. There are 2 very minor spots I noted as having a defect under the anno. Not really visible unless going over it with a 'fine tooth comb'.
The plastic piece that contacts the handlebar/headlight mounting bar. One of the issues with weather resistance is underneath this plastic piece.
Water will very easily be able to enter the underside of the head where the wire enters. (This can/should be remedied with a dab of silicon adhesive)
Attached to the Headlight strap dealie... The silicon attachment piece provides a snug fit; the angle adjustment is far better than any of the snap/clicking angle adjustments that wear down over time. I can see this lasting quite a while. The actual piece that makes contact with one's head is adequately padded. It is quite comfortable despite the rather large size of the light itself. While the size is adjustable, the strap may be too small if you have a large head (I have a medium-large head and it is comfortably snug at the maximum adjustment size).
Here's a look at the battery pack holder. It is a bit on the cheap side. Definitely not waterproof.
Velcro front flap and velcro attachment strap in the back.
Here's the provided battery pack. This is the second point of water/dirt vulnerability. The 2 caps on the pack are cardboard/paper and there is an unsealed path along the wire for water to easily travel along.
Size Comparison (and quick beam comparison):
Koolertron Headlight/Bike Light, Trustfire L2M (P60), Tangsfire C8, Maglite 2AA
You can see this light is essentially the size of a C8 head. And interestingly, the bezels are directly interchangeable. The reflectors are identical in width, but the Tangsfire is a bit deeper.
Quick comparison Tangsfire C8 vs Koolertron.
Note: the Tangsfire C8 is driven at 3A, the Koolertron is driven at 1.6A.
Mouseout Koolertron.
Mouseover Tangsfire C8.
Breakdown:
Very smooth triangular cut threads. Lens is glass without a coating.
Here you can see the 2 stage reflector. Light OP for the first 25% and smooth for the remainder.
The XML led is thermal pasted onto a solid shelf pill. The pill rests on a ledge inside the head. The retaining ring snugly tightens the pill onto said ledge for decent heat distribution at the low drive current of 1.6A.
Conclusion:
This is an okay light. It's probably too big for most who are looking for a headlight to use for more than a few hours at a time. As a bike light I wouldn't be comfortable making similarly long trips of more than a few hours without first fixing the weather vulnerabilities (Wire hole on the underside of the head, and battery pack). I would only use the included battery pack as a backup unless around 60 minutes of high mode is adequate to you. Once these issues are fixed you'll have a rather nice, long lasting headlight/bike light.
In my eyes the light itself has a value around $25, and the battery pack and charger doesn't quite make up the difference. I rate this light a 3 out of 5.
