Friday, April 27, 2012

Techie Tuesday: Mounting Helmet Lights

After crashing in Feb, I replaced my Bell Ghisallo with a Bell Volt, and have had to experiment a little to find good mountings for my summer lighting. The Blackburn MARS 3.0 taillight was pretty easy, and very similar, but mounting the Fenix LD01 flashlight in front, to use as a map light, and/or emergency headlight, required some innovating.
Overall, a pretty light and slippery lighting system. The Fenix starts in Med mode, and is switched by quickly twisting the front of the light to toggle it through its 3 settings. Med-Lo-Hi. Nice that that's a 1-handed operation!

MARS 3.0 taillight is offset 2.5" from the back of the helmet, which makes it visible except from directly ahead. Combined with the headlight, it makes it easy for motorists to figure out where I'm looking at night.

The Blackburn mounting system uses what is essentially a plastic hose clamp. It works very well with the addition of a wooden dowel as a "soft" spacer. No need to over tighten. Easy does it!

Mounting system is minimally intrusive on the human side of the helmet

Bug's-eye view of the Fexix LD01 "headlight"

At .5oz for the Fexix, and whatever the AAA weighs, this little guy (20mm) is 1/10th the weight, and 1/5th the size of most headlights, so it doesn't grab much wind, nor block your helmet's cooling vents

A little hook-side Velco stuck to the helmet, and then a Velcro wire bundle tie looped over the top, makes a nice soft, movable/adjustable mount for lighting the cockpit, and/or, the road.

The back of the flashlight body was wrapped in a 3" strip of soft rubber gripper, held in place with a tiny zip-tie. It was pillfered from another mounting kit. Hollow back aids cooling.

Detail of inside of Velcro mount. Note it is "clamping" on solid Styrofoam, so not compressing two unsupported slots together.

I left a small slot at the top of the flashlight uncovered when wrapping it with loop-side Velcro, to allow for better cooling. The light, if anything, tends to push air into the front slot, and suck it out of the rear slot, improving overall ventilation
Based on a suggestion made on, I inserted a LION 10440 cell into the Fexix LD01. It's very bright anyway, but the 72 lumens jumps to about 225 with 3.7 volts pushing it, instead of 1.25 volts. On the lowest setting it produces about the same light it's supposed to on the 27 lumen setting. On med, about 100 lumens, and I'm scared to leave it on high for more than a minute as it gets hot fast.

I'm going to experiment with this setup a little, but can't recommend it at this point. On low the 10440 cell only lasted 2.5 hours, so not much on endurance. I may try the medium setting with the flashlight in my freezer just to see if it's the LION cell's voltage regulation circuit that is limiting it's burn time, not power drawn. Happy trails!


Tim Gates said...

I recently bought an LD01 and a couple of 10440's for it, as I'd heard how bright it could be. I am delighted with this light for general use, and amazed at how bright it is using the 3.7V cells. I only run it for a few seconds at a time on the higher 10440 outputs, as it does get hot very quickly.

Have you noticed any problems with your 10440 cells after using them in the LD01? Mine have gotten squished down, so the pole is almost flat with the top, instead of sticking up like it did when new. I expect this is due to the fact that the cell is slightly longer, and twisting the LD01 down to turn it on must be pushing the top down more than it would an alkaline cell.

I'm concerned about the health of my 10440 cells, since it would seem that compressing them isn't doing anything good for their structural integrity.

Grey Beard said...

I'm not impressed with the 10440 cells. They don't seem to hold the advertised power, and except on low, I don't trust the reliability with the excessive heat generated.

For testing the higher settings, I'd RX dropping the flashlight in ice-water after turning it on "HI".

I usually have the light in default mode with the stock NiMh battery, as that fills in ahead of my MagicShine bike light without diverting my focus, so not sure why I'd want to risk damaging the light for brightness I don't need.

In very cold conditions, the light might be OK using the 10440s, like riding in winter, but also not when you want to risk ruining the light.

I think the best decision is to just buy a single 18660 Fenix flashlight, and use it at spec.