no1mad 

The part that I highlighted? You're right, there isn't anything stopping anyone from using ultra-powerful lights...yet. I suspect at some point, somebody who has the attitude of "I'm gonna keep adding lights until everyone has to stop in their tracks until I pass- I shall be seen!" is going to run afoul of a local politico who will then write up a bit of legislation to regulate the amount of light one can use.

Sixty Fiver

We are now seeing bicycle lights that are as bright as good quality car headlights... problem is that many of them are poorly built and throw light where it is not needed and this poses hazards to other road users.

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.

cyccommute 

This constant worry about bicycle lights baffles me. Do you people not look at your lights when you ride? Do you not think about where you ride on the road? We bicyclists "share" the very, very, very right side of the road with the exception of those countries where we have to share the left side of the road. Every "bad optics" light I've owned doesn't even come close to spraying enough light over into the lane of on-coming traffic to be of any concern whatsoever. On a regular roadway, I'm no closer than 11' to 15' from the nearest car coming towards me. Light emanates from the lamp as a cone in a straight light. Unless I do something silly like suddenly turning in front of the car coming at me, there is little chance that the light from my lamp will get into that other lane.

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.

dougmc

They aren't 1800 lumens, but as you said, 800 lumens is likely. (Note that "this type of light" has been a moving target, with different emitters used. In general, the newer ones are better than the older ones.)

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.

It's insubstantial over a few hours, but if you leave the light plugged in for days it'll drain the battery completely, so you have to unplug the connector when you put the bike away. Also, if your bike is locked, the flashing light screams "steal me" so you need to unplug it or remove the light entirely.

ItsJustMe

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.

vol

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 .

It seems the battery pack contains 4x18650. Will it be easy to replace the batteries once they are dead? Has anyone done it?

Sixty Fiver

So what you are saying is that quality lenses are important.

Thanks.

wphamilton

I just leave it unplugged after charging, a good compromise if only indulging my OCD.

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?

cyccommute 

The Magic Shines I've owned and the clones that look like them have all been more like the 35 degree floods I used to run with halogens. I have some other lights that aren't like the Magicshines that are a much tighter beam, more like a 20 or 25 degree beam which are very spotty. The cone measurements I've run fit those numbers.

No. What I'm saying is that worries about "blinding" traffic don't know what they are talking about. They certainly haven't done their homework.

Sixty Fiver

MS and Cygolites are well made and these are what I would consider good quality lights.

dougmc

You don't need to solve an equation.

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.)

Robert C

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?

no motor?

I too wonder why more people don't use them. The posters here that use them all seem to really like them, and I've found the MC light with the wide angle lens works well when combined with a thrower on the helmet.

GeneO 

+=1. I have been following these discussions and I just don't get the concern of blinding an automobile with almost any bike light.

vol

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?

dougmc

The strap it comes with is meant to use as a headlamp without a helmet. It works, though the light is a lot heavier than most headlamps so it feels "weird".

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.)

01 CAt Man Do

Well join the club. In over 40 yrs of professional road driving I've never been blinded by a cyclist on the road. On trails when passing within a few feet head on...certainly. In those situations you just slow down and turn your head or look down. The visor on your helmet can be real useful.

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. (?)

vol

Thanks. Yes, I thought that's probably the case; otherwise when you dismount the bike you'd be pulling the cable between the handlebar and your head

tcs

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?

Or pull off and stop to let the visual purple regenerate.

tcs

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?

01 CAt Man Do

Actually, lower powered lights get mentioned all the time but was not the subject at hand. Certainly the technology for a bright halogen lamp existed when I was a kid although people weren't really into night bike riding back in those days. Regardless, the point I was making was that I spend a lot of time on the road at night behind the wheel and that anywhere in those 40yrs I referred to I've not been blinded by a cyclist while driving on the road. Yes, brighter lamps are more available today. With that said it doesn't change the point I was making with my previous statement one iota. Sorry if you didn't find that additive to the discussion.

cyccommute 

I stretch it a lot and overwrap it when I install it. Although it doesn't have an adhesive, it is a little tacky as well so it sticks to the bars.

Bandrada

I simply cut the mount from the straps and use reusable zip ties to mount it as a headlamp on my helmet. It works really well and adjusts very easily.

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.

vol

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.

Bandrada

It took about that long for mine to fully charge when I first got them, or when they are fully drained. The indicator light should red, orange/red, and then green. If they do not charge completely after 12 hours I'd make arrangements to return them. At $20 and $40 they are still a bit of a gamble.