Putting a car headlight on your helmet is going to get you noticed and maybe not in a good way.
I am not a fan of over regulation but the whole light race has really been grinding on me since it seems to be all about me me me and often shows a lack of consideration for those people we share the road with.
You also have to take into account the spread of the beam. If you have a narrow spot, the intensity of the beam is higher but the spread is lower. If you have a wide flood, the intensity of the beam is lower but the spread is more. Since the beam spreads from the lamp in a cone, it's a simple math problem it calculate the amount of light per area (i.e. lux) at just about any distance. Most of the Magic Shine and their clones are floods with a 35 degree reflector. At 10m (roughly 30 feet for the metrically challenged), the area covered by the beam is 31 square meters. Solving an equation for the radius of the circle, I get a circle with a diameter of 6m but only half of that shines into the roadway. That's not enough distance for the light to get to the dividing line, much less get into the eyes an oncoming motorists who should be a few feet further over.
By using the area of the circle of light, assuming a homogenous beam (it isn't) and knowing the output of the lamp (600 lumens), I can calculate a lux for the beam. It's 19 lux which is significantly below your 40 lux lamp. The way that you can get 40 lux out of a your lamp which probably has a lower output is having a very narrow beam. Lots of light, no spread.
It's not the best out there, but it *is* the best value for the money, by far. The biggest problems they have is with the battery pack sometimes wearing out faster than expected -- the problems you're mentioning would suggest that either 1) you're not plugging it in all the way or 2) you got a bum unit. If #2 , you could send it back and get another, or just cut out the connectors and replace them.
The rubber ring mount can slip as you've seen (and others have told how to fix that) but it's very strong -- I've never had it fall off.
As for how far the beam extends, well, some people want a tight beam and others want a wider beam. In that regard, you can't please everybody.
The PB headlight that ThomasMcA suggested doesn't even come close to comparing to this light, even though the price is similar.
The cheap little magicshine knockoff that I have has a very spotty beam, almost all the light goes into a narrow cone. I slapped a wide angle lens on the front of it for $6, and it's actually got a very nice beam now. It's very short top to bottom, and covers the entire lane at about 25 feet from the bike. Most of the light goes farther away, there's enough low spill to light in front of me, but the high spill is minimal and no worse than a car's low beam. About $40 total.
Mine has such wide and close spread that it's like a large light ball around me; probably hard for a driver coming from the side to tell which way I'm travelling. OTOH, the flashlight shoots forward an obvious beam and does not illuminate much at the source (near my body), but it's very successful to alert pedestrians making them think a car is coming from behind :D.
It seems the battery pack contains 4x18650. Will it be easy to replace the batteries once they are dead? Has anyone done it?
The battery pack is only 4400 mAh but I'd be surprised if the green light discharged it in less than 4 days or so. Not enough to worry about if you ride every day or commute IMO. I'd wire a toggle switch in if it bothered me.
I don't understand "steal me" though. Surely even bike thieves realize that any light has power to it, lit up or not?
10 meters * tan(35 degrees) = 6.1 meters.
That said ... the Magicshine beams aren't that wide. There's a weak beam that's larger than 35 degrees (it's over 90 degrees), but the "bright spot" is more like 10 degrees in diameter.
If you want a wider beam, you can buy this which works pretty nicely -- turns the beam from about 10 degrees horizontally and vertically to 30 degrees horizontally and still 10 degrees vertically.
Now that I'm looking into this, this page is interesting -- they actually measured the beam pattern. I guess we need to precisely define what we mean by "the beam", but if we mean "where the intensity is at least 50% of the peak", the beam is right at 10 degrees in diameter for the MJ-808 and about 17 degrees for the MJ-880.
At 17 degrees from the center (half of 35 degrees), the light intensity for the MJ-808 (the classic Magicshine) is about 3% of the peak.
That said, some of the clones use different reflectors, and that makes a big difference. I've seen some with smooth reflectors and some that are "dimpled" almost like a golf ball -- the dimpled one has a wider beam, but the smooth one is more like 10 degrees.
I think I've bought five Magicshines and clones now, and the bright spot has been 10-20 degrees in size -- I've never seen one that was 35 degrees wide. I also purchased one of those lenses I mentioned, and it works as advertised, though I have realized that I prefer a narrower beam. (Though it's good for a second light.)
edit: I measured the beam width on the most recent Magicshine clone I purchased (the $20 Amazon model, ordered it last week, it arrived Wednesday.)
Putting the light on the floor, the bright spot of the beam was right at one foot wide on the 8' tall ceiling -- which works out to a beam width of arctan(1/8) or about 7 degrees in diameter. The beam intensity dropped off quickly past that.
The widest part of the beam (the part that came straight off the emitter, not being reflected) was about 90 degrees wide.
I did find this one to have the tightest beam of any of the Magicshines or clones I've bought (visually -- I haven't measured the other ones.) It also seems to make the most light, though I'm not sure if that's because of more light or just the tighter beam. (I don't have the needed equipment, such as an integrating sphere, to properly test such things objectively.)
I am also running a Magic Shine clone. However, I am running it with a defusing lens in order to get a wider spread with a something resembling a cutoff.
Questoin, I do not see the defusing lenses mentoined here often even though amazon puts them on every page with the MC clones, is there a reason people do not like the defusing lenses enough to not use them; if so, why?
For those of you who mount the light on the helmet, where do you put the battery pack?
Also, has anyone tried to mount the light to his head without wearing helmet, using the helmet strap? would it work?
As for where to put the battery, the easiest place is in your pocket or strapped to your belt. You could mount it to your helmet and coil up the wire, but it's kind of big for that and the weight on your helmet might be annoying. Or it might not -- I have not actually tried mounting it to my helmet. (But have used the headlamp strap without one.)
Nope, only thing every blinded me while driving down a road / highway is overly bright car, truck, ERV's, and highway crew work lights. On rare occasion I have been blinded by a motorcycle but it was a Motorcycle with three head lamps. Two ( lower mounted ) which looked to be LED and were quite bright. Then again it was only an issue for about 10 sec and yes he did lower his lights when I approached.
@ Cyccommute, thanks for the tip on that Tommy Tape stuff. I'll have to buy a roll of that to try out. I'm curious though, if it doesn't stick to the bars how does it stay in place? I know it sticks to itself but unless it holds to the bars I would think it might start to rotate if enough pressure is applied. (?)
Uh, has anyone here been talking about the 3W filament bulbs we used 40 or 20 years ago, or the 3W halogen bulbs we used 10 or even 5 years ago? :)Quote:
In over 40 yrs of professional road driving I've never been blinded by a cyclist on the road.
Or pull off and stop to let the visual purple regenerate. ;)Quote:
On trails when passing within a few feet head on...certainly. In those situation you just slow down and turn your head or look down.
Given a hypothetical choice between two otherwise identical headlamps, one with a plano and the other with a beam shaping lens that directed the photons to some advantage, which would you choose?Quote:
I have been following these discussions and I just don't get the concern of blinding an automobile with almost any bike light.
I'm really digging these lights at the $60 price tag. I also bought a battery upgrade for $18. The flood light lasts about 2.5 hours at full output. They are used primarily for offroad. I choose not to use the diffuser as it's plastic and severly degrades the beam. Besides, I have gotten used to having the spotlight on my helmet and the flood is more than enough for the bars.
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How do I know when the battery is fully charged? In my case, the indicator light on the charger is always red even after 7~8+ hours as long as it's plugged to the light; but whenever unconnected to the light but plugged to outlet, the charger indicator is always green.