This is a follow up to an older post where I compared the Planet Bike Blaze 1W light to the 2W light, specifically noting that the 2W on low was brighter than the 1W on high.
According to the Planet Bike website, the 1W and 2W have run times of 7/14/20 (low/high/flash) and 5/12/18 hours, respectively. This time I wanted to compare the runtimes on low versus high, as my past measurements have indicated that advertised runtimes were not very accurate. The specific issue is that there may be some disadvantages to running these lights on the low power mode.
In this picture, I am holding two 2W headlights, waving them in front of a camera, with the nearer one on half power mode, and the other at full power. It is clear that half power is being achieved by modulating light intensity. Others have noted (on candlepower forums and elsewhere) that these lights can interfere with other bike electronics when the lights are being modulated in this way.
I ran tests on a Planet Bike 1W Blaze, the PDW Cosmic Dreadnought, and two Blaze 2W lights. Initially I was getting some anomalous results, and so I bought a Maha Battery Charger that measures battery capacity, to ensure that there wasn’t a large variation due to differences in battery capacity. All batteries with either the Duracell white top rechargeable NiMH AA’s or the Eneloop equivalent. All battery capacities were between 1876 and 1981 mAh, the nominal capacity of the batteries being 2000 mAh.
Measured run times on high were:
- PDW 4.5 hours
- Blaze 1W 13 – 13.5 hours
- Blaze 2W #1 9-10 hours
- Blaze 2W #2 17 hours
Measured run times on low were:
- Blaze 1W 18.5 hours
- Blaze 2W #1 13.5 hours
- Blaze 2W #2 25 hours
The runtimes for the Blazes on either high or low were longer than advertised. The bigger surprise was the one of my 2W Blaze lights performed much better than the other. I believe that they were bought around the same time. I also checked this result by putting slightly higher capacity batteries in one and then the other, but I got the same result. The run time for the PDW light was about the same as an earlier measurement.
Here is a video:
In terms of the comparison between high and low, you will have to decide whether low mode is worth an addition ≈40% more runtime. For my money, I’m not going to bother running any of these lights on low mode. I have no explanation for the difference between the two 2W lights, and I note that the runtime on the better 2W light is longer than the 1W. The discrepancy between the two 2W lights was the reason that I was getting inconsistent results the first couple of times I ran this test.
Any of these lights is a good be seen light, especially in this season of long, dark nights.