I just got an Astrolux S41 using BLF firmware and saw the “bike mode” for the first time. I really like the concept of the light being constant on, then adding the turbo strobe on top of the constant light. I’m considering changing up my bike lighting setup because I like it so much.
But I was concerned about the constant light output level on the bike mode, and that it may not be enough light. From measuring at the tailcap of the S41, it appears that the bike mode pulls about 0.36A consistently (with spikes during strobes). I assume the Bistro FW would be similar. What kind of output would I expect from an XP-L HI triple at 0.36 amps?
I’m looking at the data sheet on Cree’s webpage, and the Relative Flux vs Current graph for the XP-L HI suggests that 0.12A would be maybe 10% relative luminous flux, or ~45lm for a V2-binned LED. Does it sound about right that I should expect about 140lm from an XP-L HI triple in bike mode?
In addition to a focused directional headlight, I currently use two P60 single LED lights on my handlebars running either Level3 (0.9A, ~400lm?) or Level4 (2.2A, ~800lm?), depending on the traffic/road conditions. I like the idea of the integrated strobe and would like to replace one of the P60s with the above mentioned XP-L HI triple, but I’m trying to figure out how much overall output I will lose, using the Bike Mode.
I think your estimate sounds about right. It is a lot less light so you will have to try it and see if it is enough.
Personally, I use the Bistro bike mode when I’m riding in twilight, when I need to be visible more than I need illumination to see. At night I just use normal modes because the bike mode is not enough when I’m riding fast.
Your experience pretty much answers my question nearly completely right there, lol. I bike commute to work once per week in complete dark in the morning, about 1.25 hour each way, in a mix of about 70% lonely country roads and 30% traffic. I cruise at a quick pace (20+mph) so having enough light thrown far enough down road is important.
I guess if I want blinky capability then I’m still looking at adding another light. I was hoping that maybe this light firmware could do double duty, but the numbers and EasyB’s experience say no. Dang.
For the right price, could someone custom code firmware that changed bike mode from the current 0.36A, to something like 1 or 1.5A?
If you already have the S41, the triple will probably be very close to the same lumens, so you can try it out yourself. Yes, the driver can be reprogrammed to higher values.
Yes, but I’m at work now, where I can access Cree datasets but not two flashlights, a bike, and a dark country road.
Edit: regarding the bike mode customization, is that something that Richard at mtnelectronics could do for an extra fee? I was already planning to order all the parts from him if I went forward with building this light. Or would I need to reach out to one of the modders on BLF? I’m not software minded enough (or set up with the equipment) to do it myself, I think.
Richard is pretty busy. I would recommend having someone here edit the firmware file first, then you can just send richard a Hex file with your order and all he has to do is hit two buttons on his computer to flash it. He’s happy to do that.
