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-   -   How many lumens do I need? (http://www.bikeforums.net/electronics-lighting-gadgets/919190-how-many-lumens-do-i-need.html)

JerrySTL 10-25-13 07:38 AM

Quote:

Originally Posted by Garfield Cat (Post 16190821)
I want to know more about "aimed optics". Cars have both low beam and high beam. Are we saying the high beam is aimed like the low beam? Or are we saying the high beam is not aimed the same and even aimed higher like the bicycle lights nowadays?

I suspect the car high beam is meant to aim higher for the roads that do not have street lighting. That would be like a bicycle riding in the dark where the street lights are not particularly there for you. On a bicycle, it may not be practical to have both a high beam and low beam setting like a car. That would require two types of "aimed optics".

The high and low beams of a car are aimed differently. Many cars have different bulbs for the high and low beams and these bulbs are placed differently in the headlight fixture or even in a different fixture.

Even those that use the same bulb (H4 and its variants) have different filaments for high and low beam. The filaments are about a quarter inch apart which means they reflect somewhat differently plus one of the filaments often has a reflector built on it to change the light beam. Here's one to look at:

https://c808505.ssl.cf2.rackcdn.com/...1327475610.jpg

cyccommute 10-25-13 07:40 AM

Quote:

Originally Posted by ItsJustMe (Post 16190813)
You realize that the lumens rating on those lights is theoretical, right? In reality they probably put out half that. They rate them at the theoretical maximum light output as stated by the manufacturer of the LED emitter, assuming that you get the best of the best, top bin select LEDs from the batch and drive them with a perfect driver circuit with a large, efficient heat sink. This is never the case.

However, I do agree that those lights are the way to go these days. I can't think of a good reason to spend double or more for a name brand light. My current lights are a 5 year old MagicShine still running strong and a 1 year old, $35 "1600 lumen" ebay light with an Action LED lens on the front. They're both all I want in a light. I can run them on medium pretty much any time and be perfectly happy.

Actually the ratings on those lights are closer to actual output than what is claimed for the single emitter lights. The Cree U2 emitter has an output of around 700 lumens per emitter. They are a little inflated but not as much as other's claim.

ItsJustMe 10-25-13 07:53 AM

Quote:

Originally Posted by cyccommute (Post 16191044)
Actually the ratings on those lights are closer to actual output than what is claimed for the single emitter lights. The Cree U2 emitter has an output of around 700 lumens per emitter. They are a little inflated but not as much as other's claim.

Good to know, thanks. In 10 years or so when my Magicshine finally croaks maybe I'll look into what's available then :)

mrbubbles 10-25-13 08:07 AM

Quote:

Originally Posted by ItsJustMe (Post 16190813)
You realize that the lumens rating on those lights is theoretical, right? In reality they probably put out half that. They rate them at the theoretical maximum light output as stated by the manufacturer of the LED emitter, assuming that you get the best of the best, top bin select LEDs from the batch and drive them with a perfect driver circuit with a large, efficient heat sink. This is never the case.

That first one is more like 1500 lumens (mine is the 1200 lumen version). The heatsinking has gotten a lot better. You folks should really check out http://forums.mtbr.com/lights-night-riding/, way more info on lights.

cyccommute 10-25-13 08:11 AM

Quote:

Originally Posted by Garfield Cat (Post 16190821)
I want to know more about "aimed optics". Cars have both low beam and high beam. Are we saying the high beam is aimed like the low beam? Or are we saying the high beam is not aimed the same and even aimed higher like the bicycle lights nowadays?

I suspect the car high beam is meant to aim higher for the roads that do not have street lighting. That would be like a bicycle riding in the dark where the street lights are not particularly there for you. On a bicycle, it may not be practical to have both a high beam and low beam setting like a car. That would require two types of "aimed optics".

"Aimed optics" isn't like a car's high/low beam. The light is shaped so that it doesn't have as much spillage upwards as round beams do. If you go over to MTBR's light shootout for 2012 (follow my link above), you can see the Phillips Safelight compared to round beams. There are, however, some philosophical differences in shaping beams (to say the least:rolleyes:). The Europeans like to have car beams that have sharp cutoffs with zero upward spray of light. SAE rules in the US says that car headlights should have some upward spillage to illuminate signage. There is something to be said for some upward spillage especially in more rural areas without a lot of ambient lighting.

There is a something to be said about having some upward spillage for a bike light in an urban setting. My lights are competing with thousands of other light sources. If the beam is too tight or the cutoff too sharp, the on-coming traffic that is turning across my path and that I want to alert to my presence may not see the light. Since my lights also see some off-road use, I want spillage upward to indicate overhanging trees and brush that I might slam my head into as well. And let's face it, high intensity bicycle lighting in the US is aimed at off-road applications not at the commuter. The "commuter" market in the US is usually the cheap (and ineffective) "be seen" lights.

Quote:

Originally Posted by dbg (Post 16190993)
Not sure about lux to lumen conversions, but my dyno-hub driven lumotec (B&M) 30 lux headlight paints a very nicely bright window pane of light onto the road about 15+ feet ahead of me. I commute through quiet streets in Naperville, IL to the train station and this is plenty of light. A buddy has a similar lumotec with 60 lux (also dyno-hub driven) and that thing is amazingly bright.

I highly recommend the dyno hub concept. No battery worries ever (I do carry backup battery powered head and tail lights in my backpack -but have never used them)

I buy mine from peter white. Never shopped around because I like the helpful and friendly feel when dealing with them.

This shows the problem with using lux as a stand alone measure. I have a battery light that is a 150 lux lamp. What does that tell you? Nothing really. Can I compare it to yours? I don't know. Without context, you can't know anything about the lamp. If I were to tell you that my lamp puts out 650 lumens, you could compare it's output with yours if you knew the lumen output for your lamp. However, you can't really calculate the lumens from your lamp because you don't know how far away from the lamp the lux measurement was taken.

I arrived at my 150 lux measurement by taking the angle of the beam (25 degrees), the distance from the beam to the target (4 meters or about 15 feet) and calculating the area of a cone's base to give me the area of the target in square meters. If I moved the target further away, my lux measurement goes down. If I move it closer, my lux measurement goes up. But given a lux number without reference to how far away from the lamp the lux is measure, I really can't tell whether your lamp is as bright as mine or not. I could just as easily take a 60 lumen light, move the target a few millimeters from the front of the lamp and claim several hundred lux. Since the target is tiny and the area is small, the luminous flux over the target is huge.

ItsJustMe 10-25-13 09:23 AM

Quote:

Originally Posted by mrbubbles (Post 16191107)
That first one is more like 1500 lumens (mine is the 1200 lumen version). The heatsinking has gotten a lot better. You folks should really check out http://forums.mtbr.com/lights-night-riding/, way more info on lights.

I never get anything useful from those reviews because they only review name brand lights, and not even all of the popular brands. it looks a lot to me like they review brands that advertise with them. I've not seen Dinotte in their shootouts for instance. I've not seen any Magicshine lights there either.

mrbubbles 10-25-13 10:05 AM

Quote:

Originally Posted by ItsJustMe (Post 16191325)
I never get anything useful from those reviews because they only review name brand lights, and not even all of the popular brands. it looks a lot to me like they review brands that advertise with them. I've not seen Dinotte in their shootouts for instance. I've not seen any Magicshine lights there either.

Not true, check the forum out, users on the forum review a lot of ebay/dx/fasttech lights. "popular brands" like cygolite, niterider, light & motion get very little attention compared to lights from chinese sellers on that forum.

hamster 10-25-13 12:10 PM

Quote:

Originally Posted by cyccommute (Post 16191036)
I've got to agree with mrbubbles on USB. USB is relatively new and isn't any kind of standard, de facto or otherwise, especially when you consider what the market has to offer. Midrange lights aren't in the $60 to $100 range anymore. That's high end compared to what's available for $20. Even weak "cheap" lights that run on AA are expensive (and worthless, IMO) compared what's available on the market. The Cree's that are currently available put out 10 times the light that the "cheap" lights put out for about half the cost. There's a little more bother in charging and maintaining them but that's minimal.

Just look at headlights on Amazon. There are basically three groups. "Cheap" lights, usually with no mention of lumen rating: AA or AAA batteries. Brand name lights (Cygolite, Niterider, Serfas, MagicShine) up to 1000 lumen: all USB. Everything rated 1000 lumen and above (both brand name and China): all with custom chargers.

It's quite simple. Custom chargers are a hassle. USB is convenient, and, if you make a rechargeable headlight, the only reason not to do USB is if you need a big battery that would take forever to charge through USB. And you only need it if you have a very powerful light.

10 Wheels 10-25-13 12:14 PM

I find the USB charging to be more of a hassle.

noglider 10-25-13 12:54 PM

Interesting that different people have different minimum values for lumens. I need a lot less than most people here for some reason.

mrbubbles 10-25-13 01:06 PM

Quote:

Originally Posted by hamster (Post 16191862)
Just look at headlights on Amazon. There are basically three groups. "Cheap" lights, usually with no mention of lumen rating: AA or AAA batteries. Brand name lights (Cygolite, Niterider, Serfas, MagicShine) up to 1000 lumen: all USB. Everything rated 1000 lumen and above (both brand name and China): all with custom chargers.

It's quite simple. Custom chargers are a hassle. USB is convenient, and, if you make a rechargeable headlight, the only reason not to do USB is if you need a big battery that would take forever to charge through USB. And you only need it if you have a very powerful light.

Charging in general is a hassle. USB lights need to be recharged often. That's why dynamo lights are still supreme.

Quote:

Originally Posted by noglider (Post 16191975)
Interesting that different people have different minimum values for lumens. I need a lot less than most people here for some reason.

My ideal minimum is 500, max is 1000.

noglider 10-25-13 01:10 PM

My minimum is about 150 lumens, I think.

daihard 10-25-13 01:41 PM

Very helpful thread. I've been using a Serfas Plus 250-lumen headlight and felt like I could benefit from a brighter light at night. Just ordered a Cygolite Expilion 700-lumen light from Amazon. :)

cyccommute 10-25-13 01:50 PM

Quote:

Originally Posted by hamster (Post 16191862)
Just look at headlights on Amazon. There are basically three groups. "Cheap" lights, usually with no mention of lumen rating: AA or AAA batteries. Brand name lights (Cygolite, Niterider, Serfas, MagicShine) up to 1000 lumen: all USB. Everything rated 1000 lumen and above (both brand name and China): all with custom chargers.

It's quite simple. Custom chargers are a hassle. USB is convenient, and, if you make a rechargeable headlight, the only reason not to do USB is if you need a big battery that would take forever to charge through USB. And you only need it if you have a very powerful light.

You put the lights into a different category than I would. Cheap lights, in my opinion, are lights that don't cost much. That includes just about anything below $30. I might stretch that to anything below $50. That category includes most of the "be seen (but not really)" lights that can be powered by alkaline batteries. But it also includes most of the Cree emitter lights from China. Magicshine makes a couple of USB lights but the bulk of their lights which fall in the $50 to $150 range are battery pack lights. Other companies have similar offerings. That hardly makes USB a "de facto" standard.

I would also not call the chargers for a battery pack "custom". It's a charger. It's no different from a USB charger in terms of being able to charge the battery. The plug is a little different on a USB but it's still a charger.

USB may have a few things going for it like a more compact package but they have lots of warts as well. They use a proprietary battery. If the battery dies, you have a dead light. The run time and/or output is limited. If you want to go for a longer ride with a battery pack, you can just carry extra packs. You can't really swap out the batteries in a USB light so you have to plan accordingly. The lamps themselves are bulky because they have the battery integrated. That makes mounting them on a helmet more difficult. It also might impact mounting more then one on a handlebar if space is limited.

daihard 10-25-13 02:00 PM

Quote:

Originally Posted by cyccommute (Post 16192112)
USB may have a few things going for it like a more compact package but they have lots of warts as well. They use a proprietary battery. If the battery dies, you have a dead light. The run time and/or output is limited. If you want to go for a longer ride with a battery pack, you can just carry extra packs. You can't really swap out the batteries in a USB light so you have to plan accordingly. The lamps themselves are bulky because they have the battery integrated. That makes mounting them on a helmet more difficult. It also might impact mounting more then one on a handlebar if space is limited.

I believe the Cygolite light I just ordered from Amazon has a swappable battery.

Quote:

Quick-release Li-ion battery stick can be swapped on-the-fly for extended run times, charging & low battery indicator on button for easy reference

mrbubbles 10-25-13 02:05 PM

Quote:

Originally Posted by daihard (Post 16192144)
I believe the Cygolite light I just ordered from Amazon has a swappable battery.

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That battery is $35. For $35, you can get a complete lightset that's brighter, and has longer runtime.

daihard 10-25-13 02:08 PM

Quote:

Originally Posted by mrbubbles (Post 16192164)
That battery is $35. For $35, you can get a complete lightset that's brighter, and has longer runtime.

I was just responding to cyccommute's post about the batteries not swappable in a USB light. :)

I agree, though. If you do need a longer battery life than given by one battery, this one would probably not be the best choice.

SlimAgainSoon 10-25-13 02:09 PM

On the "shaped light" question, my headlamp is such. There is very little light that spills outside the square shape.

It makes for an effective light.

I remember that when I was shopping for lights this one (a Schmidt Edelux) indicated it threw 80 lux. That didn't sound like much, but the Edelux does a fine job. Better, because so few of the precious lux are lost lighting up yards or treetops.

mstraus 10-25-13 02:58 PM

Quote:

Originally Posted by cyccommute (Post 16191036)
I've got to agree with mrbubbles on USB. USB is relatively new and isn't any kind of standard, de facto or otherwise, especially when you consider what the market has to offer.

I am not sure what you mean by USB being relatively new or not a standard. USB has been a common choice for charging small electronics for about 10 years now, and is actually a standard for the most popular type of electronics, mobile phones - literally this is required by law in Europe. Virtually everyone has USB chargers and a tone of micro and/or mini USB cables. If you don't have on they are readily available cheap.

While not everyone might like USB charging, I personally love the convenience of USB charging for both my headlight and taillight. They charge relatively quickly (time depends on if its plugged into my computer or higher power charger), and I almost always have a charging source (computer, phone charger, etc). For an office worker, its really easy to plug them in at my desk. I have a powered USB hub with the cables always plugged in on my desk. Also easy to do at home. My main complaint is that some lights are still using older mini USB vs the newer micro USB (what almost all new phones outside of iPhones use), so I need one of each cable with my current lights.

Had my lights had a dedicated charger, I would need two chargers (work and home) to make sure I could always charge if needed.

I also use a battery operate tail light as a backup (I don't yet have a backup headlight but plan to get one).

Yes, a decent USB chargeable light might cost more, and the battery might not last as long as you would like, but these are not related to USB, but to choice of the battery, brightness, and other considerations (for cost at least). Battery lasting is largely because the small integrated Lithium ion batteries the put in to save weight and size.

ItsJustMe 10-25-13 04:06 PM

Quote:

Originally Posted by noglider (Post 16191975)
Interesting that different people have different minimum values for lumens. I need a lot less than most people here for some reason.

It probably depends a lot on your route. I like 400 or so lumens because several miles of my route is on rolling gravel roads where I might hit the bottom of a hill at 30 MPH and suddenly be on washboard if I couldn't see at least 50 feet in front of me very clearly. I also can come across potholes suddenly at speed, and even large groups of potholes that formed in a day and can box me in - IE if I swerve to avoid one and go the wrong way there might be a series of them that force me in and then I get to where I can't avoid them. For these I might need to see as much as 100 feet ahead, so I can slow down if not avoid them.

When I get to paved roads I don't need that much, 200 would do fine, 150 maybe, but there's no reason to be stingy when I've got lumens on hand for the bad bits anyway.

noglider 10-25-13 04:18 PM

Or perhaps my brain processes visual information more quickly than others'. I've ridden at perhaps 20 mph, perhaps more, on totally unlit roads. This is why my Philips dyno light, rated at 60 Lux. I don't know how many lumens it puts out. Of course, it puts out fewer than sounds reasonable, but since it has that European sharp cutoff that cyccommute doesn't like, I get away with fewer than I would need with a round beam.

My wife has a NiteRider rated at, I think 170. To me, it appears to be as bright as a motorcycle beam. I think the beam is round. When she rides behind me at night, I often think it's a car behind me.

rekmeyata 10-25-13 06:17 PM

Quote:

Originally Posted by hamster (Post 16190238)
I have a 300 lumen Cygolite Metro and it is adequate for commuting (and, in my experience, outshines 90% of lights that I see at double centuries). It is plenty bright, but I wouldn't mind having extra lumens in the form of a wider beam.

There are two drawbacks of going above 300. Standard headlight design consists of a LED bulb and a rechargeable lithium battery. Good LEDs don't differ much from one another and give to the tune of 60 lumen per watt. Lithium batteries are 120-150 Wh/kg. That means that a 300 lumen headlight with 3 hour life will require a 15 Wh battery that weighs at least 100 g. (And then there's the LED itself, casing, lens, etc.) Most lights are charged through a USB port, which, by design, can't deliver more than 2.5 W, and it would take 6 hours to charge a fully depleted light.

If you go from 300 to 600 at 3 hour life, that gets you to 200 g and 12 hours to charge. Any further, and you end up with a light that's heavy as a brick and requires a dedicated charger because USB does not cut it any more.


First off your weights are not a concern, 200 grams is only 7 ounces.

Secondly they have fast chargers out now that can recharge a my 36 volt 54 watt hour weed eater battery in 2 hour, a 18 volt 1.5 amp hour battery in my drill in 20 minutes. The only reason bicycle lights are charging slower is mostly due to USB power supply. And there is a newer designed battery coming on the market that will take only 5 to 10 minutes to recharge.

Thirdly; I have a Cygolite 480 and it will run for 3.5 hours on high and takes about 4 hours not 6 to recharge via USB port if fully depleted, with a small battery that is so light that I put both the light and the battery on the helmet and can barely tell it's there.

And there are people here that run far brighter lights than 600 or 700 lumens and they will tell you it doesn't take 12 hours to recharge. The Lupine Wilma 6 puts out 2400 lumens, probably the brightest light on the market, the battery weighs 240 to 430 grams (depending on model), will take 5 to 6 hours to charge (depend on model), and will run for 1 3/4 to 3 1/2 hours on high (depending on model).

In no way would I be scaring people off from buying 300 plus lumen lights. The biggest decision a buyer has is how much brightness can he get for what he can afford, not battery weight, or charge times, or even run time unless a commute takes a certain amount of time and needs to make sure the battery will last long enough.

cyccommute 10-26-13 12:37 AM

Quote:

Originally Posted by mstraus (Post 16192332)
I am not sure what you mean by USB being relatively new or not a standard. USB has been a common choice for charging small electronics for about 10 years now, and is actually a standard for the most popular type of electronics, mobile phones - literally this is required by law in Europe. Virtually everyone has USB chargers and a tone of micro and/or mini USB cables. If you don't have on they are readily available cheap.

While not everyone might like USB charging, I personally love the convenience of USB charging for both my headlight and taillight. They charge relatively quickly (time depends on if its plugged into my computer or higher power charger), and I almost always have a charging source (computer, phone charger, etc). For an office worker, its really easy to plug them in at my desk. I have a powered USB hub with the cables always plugged in on my desk. Also easy to do at home. My main complaint is that some lights are still using older mini USB vs the newer micro USB (what almost all new phones outside of iPhones use), so I need one of each cable with my current lights.

Had my lights had a dedicated charger, I would need two chargers (work and home) to make sure I could always charge if needed.

I also use a battery operate tail light as a backup (I don't yet have a backup headlight but plan to get one).

Yes, a decent USB chargeable light might cost more, and the battery might not last as long as you would like, but these are not related to USB, but to choice of the battery, brightness, and other considerations (for cost at least). Battery lasting is largely because the small integrated Lithium ion batteries the put in to save weight and size.

I follow the bicycle light market pretty carefully and USB bicycle lights have only been around for 2 to 3 years. USB has been used for charging devices but not for bicycle lights.

Personally, I wouldn't use a battery that couldn't get me from home to work and back on a single charge. All of my battery packs will handle a 2 hour commute on high with about an hour in reserve. If I need more run time, I just carry extra battery packs. They aren't really all that heavy.

I fail to see the upside of a light that costs more, doesn't have as much power, nor put out as much light. Sure it might be lighter but weight is pretty low on my list of requirements. Kind of ranks below color and length of the velcro strap on the battery pack. And it's not like LED lights are all that portly anyway. A 2S2P 18650 Li-ion battery pack weighs in at 120 grams (less than 5 oz) and some of the headlamps are coming in around 60 grams. Not much in the grand scheme of things.

rekmeyata 10-26-13 07:24 AM

I agree Cyccommute. if a person is commuting and needs a light why be concerned about weight? It's not like they're racing back and forth to work! Then most commuters carry some sort of bag to carry a lunch, extra clothes, etc, and now they're worried about a few grams of battery weight? This argument about weight on a commuter bike is just plain nuts.

I always carry extra batteries for most of my lights. Only two lights, one headlight and one tail light, uses a battery that can't be replaced on the road, but I have 3 other sets of tail lights that use AAA's so I'm not concerned about those, and the one headlight I carry an extra set of rechargeable AA's. I don't even keep a close eye on my bats levels except for the rechargeable ones, if the AAA, AA bat powered lights run out of juice while riding I simply pull over and replace the bats, no big deal. I recharge all my rechargeable lights when I get home from every ride so their ready for the next day. The weird thing is, I'm not the least bit worried about carrying the extra weight of spare bats!!

A few commuters I knew over the years carried their rechargers to work because in the winter months they may have to ride an 2 hours or so in the dark and again at night, one guy bought an extra recharger and kept it at work.

There are ways around doing a lot of stuff to extend ride times in the dark if needed if you think about it more.

robmcl 10-26-13 08:56 AM

Quote:

Originally Posted by cyccommute (Post 16184833)

I would suggest lights like these. The advertised output isn't 1200 lumens...it's closer to 600 lumens...but it's far superior to the Knog Blinder (which isn't:rolleyes:) for a less money. I'd suggest getting at least 2 and would even suggest 3...two on the bars and one on your head...if you want to actually see stuff on the road. Three of them are still going to be less than $100. I've been using similar lights for about 2 years now as well as Magic Shines from 2 to 3 years before that. I haven't experienced any failure of the lamp, or battery for that matter, in all the time I've been using them.

This might be a stupid question, I have not had to use a bright light for communting for several years and I am still in the Battery Space halogen light relm. How does the battery on the above light charge. It it a "smart charger" where the charger stops charging automatically when the battery is fully charged?


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