Bike light technical question

With the nights getting darker I've noticed that my cheap front light just isn't cutting it. I've seen some much better options on Amazon and Ebay but they come with their own (seperate) battery packs. An example is one that is 7.4V 8000mah.
Call me lazy but I'd like a solution whereby I can charge my bike and at the same time keep this second bike light battery topped up - but only by using the one connection. Would there be any way to connect this smaller battery to my 18S 24ah main pack so that I don't have to worry about forgetting to keep the bike light battery charged up, but without having to change the current charging method - a 74V 300w Li Ion bulk charger?

Thanks
Jon

have you tried wiring your bike light wall adapter to your main pack and seeing if it will work as a dc-dc converter, you may find its able to charge from your 72v pack in which case it will charge while you ride

trying to get 2 battery packs of different capacities and voltages to charge with 1 plug and no fire is a challenge. I prefer lazy, simpler ways to make things work.

Forget about a separate battery for your light. you already have a battery on your bike. Get a DC/DC converter, wire the light to the converter and the converter to your main battery. Simple. Elegant. lazy.

I just replaced my LED strip lights in front with two of these. Since they run directly from pack voltage, if I wanted more light I'd simply add more of them. At 3w of efficient LED output apiece, it's a very cheap and effective way to get as much light as desired.

Depends what you want light for.

If you want to see, then get a light designed to put out the proper pattern, similar to real vehicle lights, but scaled for bicycles, mopeds or motorcycles, depending on the speed you travel.

If you just want a lot of light then get any old light that advertises lots of lumens, but be aware that the poor pattern will annoy others and interfere with your own ability to see well at night.

Most lights can be wired to run from a 12V or 8V DC converter, if you can't find one that runs from battery direct.

Alan B said:

If you want to see, then get a light designed to put out the proper pattern,

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Or you can get a number of lights that throw a relatively concentrated spot, like the ones I linked to, and build your own beam pattern. They don't all have to point at exactly the same spot.

I find that on a bicycle, I almost always want more light distributed above the road surface than a car's low beam gives. That's both for conspicuousness/intrusiveness to murderists, and to be able to read street signs before I'm right up on them.

Chalo said:

Or you can get a number of lights that throw a relatively concentrated spot, like the ones I linked to, and build your own beam pattern. They don't all have to point at exactly the same spot.

I find that on a bicycle, I almost always want more light distributed above the road surface than a car's low beam gives. That's both for conspicuousness/intrusiveness to murderists, and to be able to read street signs before I'm right up on them.

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You want to slightly blind the motorists do you, interesting angle there.

Theres got to be a light forum around, buying the led's then the power module then the refelectors cant b too hard.
http://theflashlightforum.com/
http://budgetlightforum.com/forum
http://www.candlepowerforums.com/vb/forumdisplay.php?55-Flashlights

markz said:

You want to slightly blind the motorists do you, interesting angle there

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When murderists stop claiming "I didn't see him" (and cops stop accepting that lame excuse) when they hurt and kill cyclists, then I'll worry about my lights being too bright, or aimed too high. Until then, I want plenty of light on the lane, but also some at windshield level. When they say the same old crap about me, I want to be sure they're lying.

The best pattern I've found is the higher quality motorcycle headlights, they have a sharp horizontal cutoff that kicks up on the right hand side to light up Chalo's signage on low beam. On high beam there's plenty above the midline to get in the oncoming traffic's eyes, but we don't use high beam when eyes are oncoming.

Sharp optical cutoffs are surprisingly difficult to make with flashlights. The Euro standards are guiding bike lights, those may be worth a look.

Chalo said:

markz said:

You want to slightly blind the motorists do you, interesting angle there

Click to expand...

When murderists stop claiming "I didn't see him" (and cops stop accepting that lame excuse) when they hurt and kill cyclists, then I'll worry about my lights being too bright, or aimed too high. Until then, I want plenty of light on the lane, but also some at windshield level. When they say the same old crap about me, I want to be sure they're lying.

Click to expand...

When I was operating a cage and approached a vehicle that shined a bright light in my face I had more of a tendency to aim at them than avoid them. Sometimes it is not a good idea to poke the bear.

Alan B said:

The best pattern I've found is the higher quality motorcycle headlights, they have a sharp horizontal cutoff that kicks up on the right hand side to light up Chalo's signage on low beam. On high beam there's plenty above the midline to get in the oncoming traffic's eyes, but we don't use high beam when eyes are oncoming.

Click to expand...

I just purchased a 5 3/4" DayMaker (Harley headlight) knockoff that I intend to mount to my front basket this weekend. The main goal is to get a broader beam and more sideways light. The second goal is to have a super-bright hi-beam for daylight riding. I just had a woman almost run me down rolling through a stop sign. I'm running a 7.5 watt LED (50 watt claimed equivalent) spot that I thought was pretty darned visible during the day. This motorcycle light will be larger put out about five times the light with the high beam on - which I expect to run only during the day.

I'm not a big fan of the sharp cutoff line headlights. If not precisely aimed, the light falls off a visual cliff at the leading edge - and this can be very disconcerting. My wife's 350z has these and I find them annoying as heck as I drive through our hilly town. They are fine on flat, unchanging roads.

These shaped beams are also LOTS more blinding when/if they do shine in your eyes because the light is projected from a smaller spot and not as spread out as with older style headlights - hence the source spot is a brighter. I also suspect the concentration of light toward the upper portion of the beam is part of the problem. That brighter portion is what you are more likely to have blasted into your eyes when lights are not properly aimed.

Maybe the problem I have is that I see pretty well at night and am consequently more sensitive to these ridiculously bright lights. I dunno, but I can assure you that bright headlights are a much bigger problem for me now with these "advanced" new designs than they were 20 or 30 years ago.

Alan B said:

Sharp optical cutoffs are surprisingly difficult to make with flashlights. The Euro standards are guiding bike lights, those may be worth a look.

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I do have one small headlight that meets the German standard. And while it is very efficient at providing even light on the road ahead, it scatters very little light anywhere else. It creates an odd effect where the road surface is lit surprisingly well for a small light, but you can't hardly notice reflective road signs until you are quite close - pretty much as though the reflective signs had no special reflective property. My "poorly" designed (but well aimed at slightly below the horizon and slightly to the right) LED Spot lights them up nicely.

wturber said:

I just purchased a 5 3/4" DayMaker (Harley headlight) knockoff that I intend to mount to my front basket this weekend. The main goal is to get a broader beam and more sideways light. The second goal is to have a super-bright hi-beam for daylight riding. I just had a woman almost run me down rolling through a stop sign. I'm running a 7.5 watt LED (50 watt claimed equivalent) spot that I thought was pretty darned visible during the day. This motorcycle light will be larger put out about five times the light with the high beam on - which I expect to run only during the day.

Click to expand...

So I received the lamp yesterday and hooked it up to do some basic testing today. The claimed rating for the lamp is 45 watts 4000 lumens on high beam and 30 Watts 2800 lumens on low beam. My observation is that high beams actually draw 25 watts and low beams actually draw 15 watts. This is with a true 12v power supply (as opposed to simulating an automotive voltage that is usually 14v+). The light specifications show a working voltage range between 12v and 30v. so maybe the lights pull more wattage if you feed them more voltage? Frankly, I'm happier that they don't pull a full 45 watts. 25 watts with all lights on actually suits me better.

There is no aim point difference for the "high" beam. Both have the same exact horizon line. There are six apparent lamp modules with their own lenses. The Low beam turns on the top three modules and the high beam seems to only add the other, bottom three. The bottom three seem to be more of a floodlight than a focused beam.

I have 18 gauge wire running to my lights and was concerned that this might be too thin. No need to worry. Charts and simply feeling for warmth shows that 18 gauge will be plenty large enough to deal with the actual 25 watt or 2 amp draw. However, the lamp housing itself gets pretty hot. I let the lamp run for an hour in still air at 70 F, and the housing temperature got up to 135 F. That's pretty warm, almost hot to the touch. That seems right on the threshold of burning. This is in still air, so it is unlikely to be a problem with a moving bike. But it may become an issue if I'm running this light during the day in our hot summers. I may add a small fan down the road.

I wonder if their ratings assumed a pair of lights? Odd to be off by half, and if they have a voltage range to 30V they must have some regulation, so would not expect a great power variation vs voltage.

I recall a survey on motorcycle lighting done long ago that found that drivers mis-estimated the speed and distance of motorcycles with daytime running lights more than those without them. They were not found to improve safety. Perhaps more recent testing has better results, but theoretical safety and practical safety are not the same.

Alan B said:

I wonder if their ratings assumed a pair of lights? Odd to be off by half, and if they have a voltage range to 30V they must have some regulation, so would not expect a great power variation vs voltage.

I recall a survey on motorcycle lighting done long ago that found that drivers mis-estimated the speed and distance of motorcycles with daytime running lights more than those without them. They were not found to improve safety. Perhaps more recent testing has better results, but theoretical safety and practical safety are not the same.

Click to expand...

i thought the same about a regulator. This is a China knock-off product. My assumption is that they are simply exaggerating or lying about the wattage. But I figured I'd give them the benefit of the doubt.

There are many studies that show improved safety with motorcycle daytime headlight use. But the problem is that i'm riding an ebike, not a motorcycle. So it is unclear if any of the studies are even applicable. I'll be using this larger and very bright headlight because I don't see how it could hurt. I do see how it might help in making me more noticeable - but mostly I'll use it because it should improve my own ability to see the road at night.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771245/
https://www.swov.nl/sites/default/files/publicaties/rapport/r-97-09.pdf

Hi,

those are my "street legal" (German STVZO) headlights that i bought and used during the last years.

Busch and Müller (BUMM) Ixon IQ and Ixon IQ Premium powered by 4x AA batteries. Sadly my IQ premium has a broken front glass that casts a shadow on the right side.

Using power from the main battery is a

Supernova E3 ebike V6s (only 6V DC) with lens

a Philips Saferide 80 Ebike that can use 6V to 48V

a BUMM IQ-X E that can use 5V to 48V (newer versions 6V to 60V)

and a Supernova M99 Pure+ that officially is 12V only,, but works well from 7V to 12V.

The M99 Pure+ is better/more light than most cars and The IQ-X E is very good, too and reasonale cheap and only uses around 6.5W in night and 3W during daytime.

For the rear I bought some Spanninga Elipse Xe that should work well from 6V to 36V (maybe 48V?) and have the same light patteren as the famous Philips lumiring which was the best rear light available if you want to ride in traffic. Reaches far, doesn't blind and is reasonable large, gives some light to the sides and has very low power consumption.

First picture shows unmodified captures. Klick on pictures for larger version.



The 2nd picture has been modified to look more like the real thing. Human eye + brain has much higher dynamic range than a digital camera...

wturber said:

I have 18 gauge wire running to my lights and was concerned that this might be too thin. No need to worry. Charts and simply feeling for warmth shows that 18 gauge will be plenty large enough to deal with the actual 25 watt or 2 amp draw. However, the lamp housing itself gets pretty hot. I let the lamp run for an hour in still air at 70 F, and the housing temperature got up to 135 F. That's pretty warm, almost hot to the touch. That seems right on the threshold of burning. This is in still air, so it is unlikely to be a problem with a moving bike. But it may become an issue if I'm running this light during the day in our hot summers. I may add a small fan down the road.

Click to expand...

(edit: I don't know why one picture shows larger than the other. They are both the same number of pixels)

Air movement is important, even with higher quality stuff...



vs.

I'm not sure why heat handling could possibly be a problem for LEDs. You don't need to have thousands of lumens all in one spot. Up to date LEDs can deliver 100 lumens per watt even with less than optimal packaging. You simply use modest amounts, like sub-10W LED units, and use as many of them as you need, in whatever type of focal pattern you need, to ride as fast as you want in the dark.

For me, that's two 3W spots directed side by side on the road surface, with spill light doing the rest of the job. But I'll admit that I don't have to go faster than 20mph in the dark. Too much to lose, too little too gain.

wturber said:

There is no aim point difference for the "high" beam. Both have the same exact horizon line. There are six apparent lamp modules with their own lenses. The Low beam turns on the top three modules and the high beam seems to only add the other, bottom three. The bottom three seem to be more of a floodlight than a focused beam.

Click to expand...

I got the light wired and temporarily mounted and found that I was incorrect about the high beam's aim point. When viewing on a dark road at night you can see that the high beam does throw a long distance, rectangular, central spot some small amount higher than the rest of the beam. It isn't so obvious when aiming at a garage cabinet in a lit garage but becomes more obvious on a dark road at night.