KC8QVO

Does anyone have any ideas on small lights that will work as head lights that run on 12 volts DC?

I run all my electronics now off of 12 volt batteries (I used to use SLA's, but I just switched to a LiPO4 last spring - world of difference on weight [much lighter] and usable power [higher voltage until very close to depletion]). What I want to do is run a headlight or 2 from the same power source.

I have an 850 lumen flashlight that runs on an 18650 battery that I mounted low on my fork. I have used a Cygolite Metro bike light on the handlebar, but I think it bit the dust tonight. The other problem is I run a handlebar bag and I really don't like the light bouncing off the bag or the map case on top of it at night. The glare it causes is irritating and the shadow on the ground is problematic. The flashlight down low works much better.

However, for as powerful as the light is I run it on a low power level to increase the run time. If I crank it up I don't get much time out of it and it starts dropping the power level incrementally as the battery gets weaker. So I don't bother - I just run it low.

If there was a way to get 12v to a light the same size as the flashlight I am using that would be ideal. That way I never have to worry about charge state so long as the 12v battery is in good shape.

I am not interested in dyno powered lights at this point in time. I know they are "wired", but I am not set up with a dyno and I am not going to invest in one at this stage of the game. I have an idea for a 12v alternator that works off the front wheel/fork - but I have yet to put ideas on paper and see where it goes. For recharging/powering the 12v battery + accessories I'd like to have around (switchable coils to control current, and in turn control drag) 3 amps at normal riding speed. Figure 14.5v for charge voltage and that is (14.5x3)= 43.5 watts. Considering dyno hubs are generally under 10 watts - yes, that is magnitudes more power. So again - dyno lights aren't where I want to go, of any type, at the moment.

I want something I can flip a switch on the handle bar or top tube that turns 12v power on and off to the light and that's it. I suppose worst case is I could build a voltage regulator board that will take what ever battery power I have and drop it to 6 volts or so, but that is complicating the system.

I half way thought of making a dummy battery for my flashlight that acts as a "battery eliminator" - slug that sits in place of the battery making the appropriate connections inside with wire leads to a voltage regulator that puts out 3.7v (or so, maybe adjustable) with 12v in. That would require making a new end cap or drilling the case of the flashlight. I am not sure I like either idea, but maybe I could get a new flashlight and donate my edc light to the "cause" and give it a try...

CliffordK

Have you looked at automobile bulbs?

You can buy LED based "clearance" light bulbs that might be suitable for a bicycle system. Hmmm, I'm seeing several that appear to be designed for high power.

I got a couple similar to these a while ago. Mine weren't particularly high quality, but seem to do OK.

https://www.ebay.com/itm/6-BBT-12-v-...1/302070057432

Of course, for red and amber, you can get fully enclosed side/marker/clearance/trailer lights.

I don't see the voltage reduction system utilized. Perhaps a simple resistor.

Tourist in MSN

If you have a 12v lighter socket with the correct polarity, you can plug a USB charger into that. You can find for about $5 USD some fairly strong lights on Ebay, shipped from asia (shipping can take a month) that plug into a USB port.

The one I have (photo below) when you plug it in, it initially is off, one push on the button and it is in high mode that runs at something like 6 watts, press the button again and you have about a 1 to 1.5 watt powered light. One problem with that is that if your power source is not strong enough to power the light on high (6 watt out of the USB port), then the light will not function and you can't even push the button a second time to get to low power. I have no clue if the 12v USB outlets for a lighter socket have that much power or not. But, it is cheap so if it does not work for you, you did not lose much money. The light I bought straps onto a handlebar or something round. It is a flashlight type of beam, circular, not low and flat like is best for a bike light.

If your handlebar bag is not too close to the tire, you might be able to mount something on the fork crown that you can strap the light too.

KC8QVO

Does that unit allow you to switch it on and off by supplying power/taking away power? IE - you can wire a separate switch and what ever mode you had the light in prior to shutting it off is what is retained over the cycle of cutting off power (unplugging) and supplying power again (plugging back in)? Or o you need to physically mess with the button on the light to turn it on and off?

The requirement of "wired" is exactly for the above - I want the power supply on/off to the light to turn the light on/off. I want the light down on my fork and I don't want to lean down to fiddle with a button on the light to turn it on/off, if that makes sense.

USB power is no problem. I run chords to all my electronics - phone, tablet, and bike computer - simultaneously. The port I use most often is a combination 12v accessory port (auto style socket) with 2x USB ports. The 12v side of the circuit (source - battery, splitter) is all Anderson Powerpole connectors. Depending on the ride and what I have going on I may run a 12v accessory plug to 3x USB port (3x usb's mounted directly to the plug, no wire) so I have the 2x in the wired port to the source plus the 3x in the adapter. However, I have other accessories that run off the 12v port - such as a battery eliminator for a handheld ham radio. So I may split off the powerpoles with another (2nd) 12v auto port just for that then I still have the combo USB/12v port for all USB.

I have a dummy stem under my bar for the bag and accessories. So the bag sits pretty low. I thought about what you describe - but to do it I would have to build a bracket to extend the light out in front further. Not out of the question, maybe I can come up with a design to do it, but for the time being low on the fork has been working well for me this fall/winter.

Tourist in MSN

When you plug it in, the light is off, but the button is lighted so you can see where the button is in the dark. The button is not visible in the photo, it is on the left side of it which is the back side of the light opposite the lens. You would have to reach down to the position of the light to turn it on or to switch to low setting. It also have a flash setting that I never use.

There are lots of USB powered lights from Asia on Ebay, the others might be wired differently, the one I showed is the only one I am familiar with.

A bit off topic, but I decided to quit mounting a light on my S&S bike when i tour on it. Since I almost never use a light on that bike when touring, installing and later removing the light on the bike was a hassle since I had to remove the light to pack the bike in the S&S case. Thus, for touring on that bike I switched to the light in the photo. I leave that light in my handlebar bag in the rare event that I need it. I can run it off of a powerbank that i also keep in the handlebar bag.

noglider 

Lights made for dynamos tolerate input voltage of 30 or 40 volts, so you'll be fine. The new lights made for dynamos are pretty darned good, especially from Busch and Müller.

polyphrast

However, those dynamo lights tend to refuse to work with a DC power source. In this case one would need to buy a light specififed as e-bike DC version. Again the Busch und Müller e-bike lights are specified to work with input voltages between 8 and 48 V.

angerdan

Ebike headlights mostly accept 12V DC:
bumm.de/en/products/e-bike-beleuchtung/parent/164/produkt/164r60ts7-01.html
supernova-lights.com/en/products/e-bike-lights-25kmh/m99-mini-pro-25/
supernova-lights.com/en/m99-mini-pro-45/

noglider 

Are you sure all of them do that? Someone reported here that he tried DC on dynamo lights and they worked fine. Maybe some do and some don't.

Tourist in MSN

You might be right, maybe some do.

But, I am pretty sure that I have read that using a Luxos U on a DC source will fry the electronics. I personally would not risk it on any expensive dyno version of a light unless someone that I trusted (B&M directly, Peter White that distributes them, etc.) said it was ok.

The e-bike version makes sense if that was made for a high voltage DC source.

Some of the dyno powered lights have electronic means of estimating your speed. Two of my lights (Luxos U and AXA Luxx 70 Plus) change their LED usage with different speeds. I have no idea how, but i would not be surprised if it was based on AC frequency. I think that the B&M brake light feature in one or more of their taillights relies on change of AC frequency to know when you are slowing your speed.

I have a couple old D Lumotec Oval lights sitting on the shelf, those are quite old as technology goes, that is the only light I would consider experimenting on if I had a desire to run a light on a DC source, but those lights might never get used again so it would not be much of a loss.

As I noted in my posting above, my first choice would be a USB powered light that I know works.

polyphrast

I can't say this for all of the dyno lights, but why else would B&M (and others like spanninga, schmidt, hermanns) offer specific dc versions?
For the B&M IQ-X it is for sure confirmed, someone even made a custom designed circuit board for the iq-x to allow use with a bike harvester system. The original electronics don't work with DC current.

noglider 

Sure, that makes sense, but why would they make lights that do work with DC and don't list that as a feature? I do not know.

Tourist in MSN

I think the person that wants to use a good light like that on a 12v or other higher voltage DC source that is not an e-bike is quite rare. Most people that are going to want a high output DC light will be using a Li Ion battery pack with it. Or, maybe like the light I posted a photo of above. power a USB light with a power bank.

noglider 

Agreed. USB power is so versatile and flexible now, you might as well use it in lots of applications. Maybe we should be talking the original poster KC8QVO into using a 5V supply.

Tourist in MSN

He is thinking he can come up with a system that puts roughly 40 watts into his battery.

I was happy to suggest a light option, because that was pretty simple and I had one that I knew would work.

But when you consider that on a good day I might average putting out 120 watts of muscle power into the pedals and even the most efficient dynohubs waste over a third of the watts that are put into them (drag minus electric output), I do not see much upside into spending much time on this topic. A back of the envelope calculation would suggest that roughly half the muscle produced watts are not going into motion if he is successful in making the hardware work. I am going to stay out of that discussion.

I use a dynohub and USB system for bike touring to keep my electronics up to charge. I have measured during an exercise ride near home on mostly flat terrain with an unladen bike, which includes some city street traffic that I was getting 2.5 watts on average out of my Sinewave Revolution into a power bank while moving. Bike touring, when you factor in slower uphills, slower speeds on the flats with a heavy bike, time at stoplights, time stopped for photos and taking in the sights, etc., I figure an average of 2 watts is more practical and that may in fact be an upper limit. So, my hardware setup is not even in the same order of magnitude of his plans.

angerdan

Booth for 12V DC:
bumm.de/en/products/e-bike-beleuchtung/parent/162/produkt/162r42-6.html
bumm.de/en/products/e-bike-beleuchtung/parent/167/produkt/167r42ts-01.html

WIshMater

LEORX 12V-85V 20W Motorcycle E-Bike LED Headlight Lamp Car - Maybe This One Will Work Out? I cant post link but Amazon sell them.

noglider 

Here is the link you can't post yet.

Tourist in MSN

If the cited 20 watts is actual power draw and not incandescent equivalent, that probably puts out twice the lumens that the high beam I had on the motorcycle that I drove at freeway speeds at night on the highway, I used a Hella 7 inch round motorcycle headlamp that used a 55/60 watt H4 halogen bulb.

noglider 

If it draws 20 watts and is LED, it's probably much brighter than needed, and remember, there is such a thing as too bright. And if it draws 20 watts, you need a really heavy battery, making it fairly impractical for cycling.

andychrist

Track lighting runs on 12V. Just get a couple mini LED spot lights, waterproof all exposed parts with silicone and clamp sockets to your bike’s fork same as you do your flashlight now. Integrate this DC Dimmer into the circuitry to work as your power button/controller and you’re all set.

andychrist

Even better, this pair: 12-80V DC 9W Motorcycle Headlight

I want ‘em!

Or this one with a slightly warmer color temperature at 6W and 650 lumens.

ChrisAlbertson

If you don't want you LED flashlight heads to did as the battery runs out what you need to look into is a DC/DC power supply. These are way-cheap on eBay. It is a littlePCB 1/2 the size of a credit card. You adjust the output volts with a tiny screw driver, then it converts what ever volts come in to the set output. This way you get constant brightness over the full life of the battery. no LED actually runs on 12 volts. If you do find a 12V LED light bulb there is a resister inside that drops the volts (and wastes power.) The DC/DC supply can by very good at over 90% power efficient