Battery Life:As claimed by Lezyne, this light will run for 1.5 hours on high (500 lumens), 2.5 hours on medium (350 lumens) and 5 hours on low (175 lumens) or flash mode (350 lumens). What I did to measure the run time is just to charge the battery to full, and turn it on at high mode, and see how long it lasts.
When the light is on, the button actually glows a different colour, depending on the charge level. Above 70%, the button glows green. Between 50% to 70%, the button is half green half red, and when there is less than 20 mins left, it will glow a steady red. When the battery is about to run out, it will switch to the low mode (175 lumens) and the button will flash red.
Half green half red. This means that it has 50% - 70% battery life left in this mode.
Steady red glow. According to the manual, it now has less than 20 mins of runtime left.
Actual timeline events during the runtime test, for the prototype:
0 mins : Test starts in high mode
30 mins: Button glows green/red
65 mins: Button glows a steady red. Supposedly less than 20mins left.
90 mins: Light still going strong!
120 mins: Automatically switches to low mode, button flashes red.
At this point, I ended the runtime test as the light has gone into power saving mode. The medium and high modes are no longer selectable, pressing the button only alternates between low mode and flash mode. I believe that for the prototype, the high mode is actually the normal Enduro mode (350 lumens), and not the Blast mode (500 lumens). That was perhaps why it lasted so far beyond the claimed 1.5 hours duration.
After I received the production model, I did the runtime test again!
Actual timeline events during the runtime test, for the production model:
0 mins : Test starts in high mode (500 lumens)
84 mins: Button glows green/red
92 mins: Button glows a steady red.
97 mins: Light flashes and automatically switches to low mode (175 lumens), button flashes red.
105 mins: Light switches off.
The runtime of 105 mins in the Blast mode is about 15 mins more than the claimed 1.5 hrs for the Blast mode, which is excellent! However, the battery indication was not accurate. The green/red LED is supposed to show when it has about 50% of the battery life left. However, it only appeared after 84 mins, which is way beyond the 50% mark of about 45 mins (half of 1.5 hrs). As such, the LED changed to a steady red (< 20 mins) only 8 mins after the green/red LED came on. Although the overall duration is pretty accurate, the intermediate battery life indication is not.
I suspect that this might be due to the new lithium-ion battery, as the voltage may not be so consistent yet, leading to inaccurate battery life indication. It may get better after a few charge/discharge cycles.
Heat Management:The exterior of the front light is full aluminium, so it will definitely help to dissipate the heat from the powerful LED. Given that the battery is a 3.7V, 2400mAh Li-ion battery, together with the constant current technology used by Lezyne, a run time of 2 hours means a constant current drain of 1.2 Amperes, which is quite high for a light of this size, proving how powerful the LED is.
Consequently, a lot of heat is generated by the circuitry, which means that the outer casing feels hot after a few minutes. In fact, during the run time test, it became almost as hot as a cup of hot Kopi-O, and I could barely hold it in my hands. It does have some sort of heat protection circuit though. As quoted from the Lezyne manual:
"Lezyne thermal protection circuit: Lezyne LED lights are protected by a thermal detection system. If the operating temperature of the light gets too high, the light will automatically change to the lowest setting. After 5 minutes, you will be able to change the light back to the previous mode setting."
Brightness Comparison with S-Sun 1 Watt and Busch & Muller IXON IQ Front Lights:Naturally, the all-important question is how bright is it? I did a quick comparison with the two other front lights that I have. The Busch & Muller light uses lux as a measure of brightness, while the Lezyne light uses lumens. There is no way to convert one measurement to another, and so the only way to compare is to shine the lights against the wall.
B&M (40 lux) on top, S-Sun in the middle, Lezyne (350 lumens) at the bottom. All at full brightness, distance about 2 metres. Note the different "whiteness" of the lights.
B&M (10 lux) on top, S-Sun in the middle, Lezyne (175 lumens) at the bottom.
Lezyne (350 lumens) at left, B&M (40 lux) at right, tiny S-Sun at the bottom.
Lezyne (175 lumens) at left, B&M (10 lux) at right, S-Sun taking a break.
B&M (40 lux) at left, Lezyne (350 lumens) at right. Distance 20 cm.
From these pictures, the general conclusion is that the B&M has a much more concentrated light beam, with a very bright but narrow shape. The Lezyne light is more yellowish, and has a larger spread.
There is another test which I did, but which I have no picture to show. I shone these 2 lights in a large dark room, at a wall about 10 metres away. The B&M light tends to fade off at the edges, and appears much dimmer than the Lezyne light, which maintains a bright and wide beam. To summarize the brightness test, the Lezyne puts out a bit more "light" in total than the B&M.
Below are some pictures showing the actual light beam when mounted on a bike.
Actual usage on the road. Medium mode, 350 lumens. More than bright enough!
Low mode, 175 lumens. Obviously dimmer than the medium mode.
Compatibility with Wireless Speedometers:Yes this is important! Especially for high powered lights that give out a lot of electromagnetic interference (EMF). I had some problems with the Busch & Muller light, as the light gives out a powerful EMF that drowns out the speedometer signals from the sensor. This happens when I use the high mode of 40 lux, but when I use the low mode of 10 lux, the EMF is weaker and the speedometer is not affected.
For this Lezyne Super Drive XL, I was pleasantly surprised to find that it does not affect my wireless speedometer at all! At all lighting modes, the speedometer worked normally. This works even when I place the Lezyne light right beside the speedometer. This is a plus point that should have been highlighted by Lezyne. Brilliant engineering by Lezyne.
Bike Mounting:With the mounts provided, you can mount the light on virtually any round bar on the bike. It even has a helmet mount, although I don't think I will mount a light of this size on my helmet? Perhaps necessary for MTB trail night riding.
I chose to mount the light at the front of the bike, using the luggage truss bolts holes to mount the front light. This means that the light does not rotate with my handlebar, and points more or less forward all the time. It also frees up my handlebar for other accessories.
Simple but secure mounting for the light.
This is a really good all purpose light, with the different modes able to adapt to different uses. The low mode of 175 lumens is sufficient for night commuting on lighted roads. In the event that the road is unlit, turn up the front light to its full power and light up your path! The flash mode is a slow flash, and some may prefer this instead of the steady mode.
If you are looking for max lumens in a small package, this could just be the one for you. The smaller sibling of this is the Lezyne Power Drive XL, which is very similar to this, only slightly smaller with a max output of 400 lumens. That may be better in some cases, as the lower power consumption means that it will last a little longer on the same battery.