6 Volt LED headlamp w/ small 6 volt motorcycle battery

[Scotchmo]

What about the amperage pull from the 2 Cree led's...?
It may be too much for the system. I have one Cree now, and it robs
the power to the to other 6 volt lights when everything is wired parallel.
This could be because I wired the Cree light straight up with no resistor
at 6 volts. It lived...but not for long.

I'll go get that 10 ohm resistor and try it.

Keep in mind, I have not started this bike yet.
I am testing everything off of 4 AA 1.5 vdc Nimh
rechargeable batteries in a series to get
6 volts total, with 2500mA common.

So Everything should be in parallel, even for both the 6 volt Brake & Tail led's...?
(They Consist of Four Led's in a Series Each and are Very Bright...
just not as bright as that Cree led...that thing is amazing)

Your batteries are not doing their job. Or you are pulling a lot more current than you think. Set your DVM leads and display for amps, run it in series with the battery when all lights are on and the motor is off. How much current are you pulling? When your lights are wired in parallel, they should not rob power from each other. When wired in parallel, each light circuit is pulling current independently from the battery. Other circuits should not go dim unless the battery cannot handle the total current. I'm assuming that you are using wire of adequate gauge.

 

[BrettMavriK]

I think there is more to this Cree led than meets the eye...

 

[Kevlarr]

With my bad batteries I couldn't run my 3 watt headlight and my 2 bulb led tail light until connected my charger and I cranked it up to over 600mA.

 

[BrettMavriK]

Scotchmo,
Tell me more about your 6 vdc lead acid battery.
Do you have the dimensions? Where can you pick one up?

I was told gel cells are the way to go , but are pricey.
I have dimension constraints, so I need a good battery , but as small as possible.
I thought 4 AA Nimhs would be hearty enough, able to take the abuse, and very
inexpensively replaceable.... I'll keep playing around.

 

[Scotchmo]

Scotchmo,
Tell me more about your 6 vdc lead acid battery.
Do you have the dimensions? Where can you pick one up?

I was told gel cells are the way to go , but are pricey.
I have dimension constraints, so I need a good battery , but as small as possible.
I thought 4 AA Nimhs would be hearty enough, able to take the abuse, and very
inexpensively replaceable.... I'll keep playing around.

I use a 6v 1.3ah Werker AGM battery. This size is common on eBay or at Batteries Plus from several different manufacturers. The dimensions are 1x2x4 inches. AGM is better than gel. Both are sealed and cannot spill even when ruptured. Many people say gel but actually mean AGM. AGM stands for absorbed glass mat. It uses fiberglass sponge mats surrounding the plates and dampened with electrolyte. You can get even smaller sizes but the size should be determined by your needs. The white wire charging setup does not put out much current and cannot keep up with an adequately sized headlight on its own. The battery acts as your buffer. Set up your 6v lights first. Decide the longest period of time that you will need to run at night with your headlight and tail light running. This determines your battery size. Than calculate your ratio of night driving to day driving that your system will allow. A larger battery allows you to drive at night for longer continuous periods of time. Lower wattage lights allow you to have a higher ratio of night/day driving.

I do most of my driving during the day so the only load is the brake light. So my battery is kept near 100% all the time. This allows me to do an occasional 20 minutes of night driving. It then requires an hour or two of daylight driving to get the battery back up to fully charged. I’m presently using an incandescent headlight. With this small battery and if I find a suitable LED headlight, I should get closer to an hour of night driving.

 

[restapukin]

thing about high power LED's is they appear to function counter-intuitively to an old ohm's law fudger like me

I'm fine messing with audio circuits & power supply circuits for same, but these LED's ... i still have a lesson or two to learn...

it occurs to me that lead acid batteries are marvellous for giving many dozens of amps briefly ... watch out if the circuit will consume as many amps as it is fed.... you end up with a WICKED FIRE-STARTER...

Y'know those 'jump starter' gizmos that have become available these last few years? What's great about these is simply having a nice safe box to carry a small lead acid battery without the risk of exposed terminals

 

[outlawbiker]

"I do most of my driving during the day so the only load is the brake light. So my battery is kept near 100% all the time. This allows me to do an occasional 20 minutes of night driving. It then requires an hour or two of daylight driving to get the battery back up to fully charged. I’m presently using an incandescent headlight. With this small battery and if I find a suitable LED headlight, I should get closer to an hour of night driving."

i was under the assumption that this charging circuit as long as it was under 3 watts of draw would allow almost indefinite run time on a lighting system? is there anyway to be able to use this system for lets say from dusk till dawn riding or lower amperage lighting to increase the run time?

 

[Scotchmo]

"I do most of my driving during the day so the only load is the brake light. So my battery is kept near 100% all the time. This allows me to do an occasional 20 minutes of night driving. It then requires an hour or two of daylight driving to get the battery back up to fully charged. I’m presently using an incandescent headlight. With this small battery and if I find a suitable LED headlight, I should get closer to an hour of night driving."

i was under the assumption that this charging circuit as long as it was under 3 watts of draw would allow almost indefinite run time on a lighting system? is there anyway to be able to use this system for lets say from dusk till dawn riding or lower amperage lighting to increase the run time?

You are correct. The 3 watts output is the peak output. The average output is usually less. If you can find a 1w headlight and a 1w taillight that meets your needs, then you might be able to drive continuously at night. The battery is still useful to regulate the voltage and keep your lights running brightly when idling or at stops. But if you want to have higher power lighting, you have to do some driving with the lights off to allow the battery to charge. My system uses over 6 watts at night. I plan on getting that down to fewer than 3 watts.

 

[outlawbiker]

forgive my ignorance on converting watts and amperage, but wouldn't the creexre-w100 led be ideal,i really dont know anything about leds, but don't they have a lower draw on juice than a filament bulb? maybe someone can fill me in or point me in the right direction of the brightest light,headlight and a simple brake light i can run on this system with in the 1 to 2 watt range or allowable with in this charging system?

 

[xlite]

,i really dont know anything about leds, but don't they have a lower draw on juice than a filament bulb?

Another popular myth is that LEDs are more efficient than other bulb types. In fact they are in the same ballpark as incandescent and put out nowhere near as much light/watt as fluorescent.

The only real advantage is LEDs have longer life than both other types. This is why I use them.

 

[Scotchmo]

Another popular myth is that LEDs are more efficient than other bulb types. In fact they are in the same ballpark as incandescent and put out nowhere near as much light/watt as fluorescent.

The only real advantage is LEDs have longer life than both other types. This is why I use them.

This is my take on it: Flourescent lights are not really suitable/available for automotive/motorbike applications, so I will focus on LED and incandescent lights. Incandescents produce a very broad light spectrum encompassing all frequencies even outside the visual range of many people. Illuminating at all these frequencies takes a lot more power than the narrower frequencies that the LED produces. With incandescent indicator lights, we usually apply a colored filter to block the unwanted frequencies. This wastes power. So for indicator applications, the LED is superior. We can use a narrow frequency LED for specific instances where we want amber only or red only indicators. So LEDs are ideal for tail/brake and turn signals. It is not such a simple decision when using in a light that is intended to illuminate other objects, such as a headlight. Ideally, a headlight needs a broad spectrum to adequately yield reflected light from a variety of different road surfaces, terrain, and objects. Just because a light is bright and easy to see does not mean that it will light up other objects. It depends greatly on the reflective properties of the other objects, and when presented with an unknown variety of other objects, we need to throw a broad spectrum at it to illuminate it adequately. A full white LED might come close, but there are a lot of variables. LEDs will use only a small fraction of the power of incandecents when used as indicators. That may not be the case for headlights. I believe there is still something to be gained by LED headlights, but the power savings of an adequate LED headlight may not be so large.

 

[Kevlarr]

Got around to hooking up the SLA battery tonight. Found a small pleather camera case on clearance ($2.49 down from $24.99 ) that fit the battery perfectly and man is that 3w LED bright! Now I just have to get some better LEDs for my tail light, could only find two "ultra bright" blues laying around and I was hoping for the blue dot look but you can barely see them through the lens. I'll probably run to Ratshack tomorrow and see if they have any of these in stock and hook up a pair in series.

 

[outlawbiker]

unfortunately i didnt have much of a chance to get to building the charging system cause lack of knowledge on what lights to use and im in a hurry to make sure the cops get off my back at night time. so.... someone led me to believe that the union generator set like the one spooky tooth sells Spooky Tooth Cycles - Motorized Bicycles: Gas Powered and Electric Bikes - Union Generator Light Set ,the lights from it would run straight off the magneto. so off i went to the local shop to find one,got the set for 40 bucks, hooked up the lights and put a toggle switch on em and when i turn the lights on it would kill the engine.so im stuck running this expensive set up off the generator,but i would have to say,it is hands down the best generator kit for a bike i have ever seen,doesn't take much to light up,and it super bright.i got flashed to turn my high beams down tonight lol!

so is there anyway to modify the charging circuit to allow the generator to take the main load of the lights while riding as the mag charges up the battery or just to use the generator to charge up the battery? so that at stop sign i could have lights at idle? it kinda becomes annoying coming to a stop and having no lights and then having to roll again to get em going. so any suggestions would be useful. thanks again

 

[Scotchmo]

unfortunately i didnt have much of a chance to get to building the charging system cause lack of knowledge on what lights to use and im in a hurry to make sure the cops get off my back at night time. so.... someone led me to believe that the union generator set like the one spooky tooth sells Spooky Tooth Cycles - Motorized Bicycles: Gas Powered and Electric Bikes - Union Generator Light Set ,the lights from it would run straight off the magneto. so off i went to the local shop to find one,got the set for 40 bucks, hooked up the lights and put a toggle switch on em and when i turn the lights on it would kill the engine.so im stuck running this expensive set up off the generator,but i would have to say,it is hands down the best generator kit for a bike i have ever seen,doesn't take much to light up,and it super bright.i got flashed to turn my high beams down tonight lol!

so is there anyway to modify the charging circuit to allow the generator to take the main load of the lights while riding as the mag charges up the battery or just to use the generator to charge up the battery? so that at stop sign i could have lights at idle? it kinda becomes annoying coming to a stop and having no lights and then having to roll again to get em going. so any suggestions would be useful. thanks again

Hook a rectifier diode to the white wire and then it will not kill the motor when powering the lights. If you want the lights to have a consistent brightness even at idle, hook up a 6v lead acid battery. The white wire/diode will keep it charged.

 

[outlawbiker]

Hook a rectifier diode to the white wire and then it will not kill the motor when powering the lights. If you want the lights to have a consistent brightness even at idle, hook up a 6v lead acid battery. The white wire/diode will keep it charged.

what rectifier diode should i get? can i get it at radio shack? and would i run it like that if i didnt use the battery? but if i do use the battery/charging circuit like you have built will i still have to keep the rectifier diode hooked up to the lights? on my light housings it says 6 volts 2.4 watts,both head light and tail light come out to 4.8 watts,also my generator says its output is 6 volts at 3 watts. if any of this info is useful.

thanks again,and im sorry if im making this painful,please bare with me.

 

[Kevlarr]

These are what I used 3A Barrel Diodes

And if you're looking to make your own LED tail light bulb replacement a pair of these wired in series work awesome!
20mA 4-pin 130° Power LED (White)

Just solder the cathode legs on one to the anode legs of the other, solder your wires to the outer legs (I snapped off the two unused legs), add a little heat shrink to all the connections and you're good to go. These actually light up the entire lens better then the incandescent bulb did and from what I've read these are the same LEDs that Ford and GM use in their side mirror turn signals.

 

[Scotchmo]

what rectifier diode should i get? can i get it at radio shack? and would i run it like that if i didnt use the battery? but if i do use the battery/charging circuit like you have built will i still have to keep the rectifier diode hooked up to the lights? on my light housings it says 6 volts 2.4 watts,both head light and tail light come out to 4.8 watts,also my generator says its output is 6 volts at 3 watts. if any of this info is useful.

thanks again,and im sorry if im making this painful,please bare with me.

The Radio Shack 276-1141 will work. The striped end normally goes toward the lights. Without a battery, the lights will be weak unless you are running at a high rpm. The rectifier diode is the charging circuit, just without the optional overcharge regulator.

 

[outlawbiker]

i found a 6 volt analog volt meter i would like to use in the charging circuit,is this possible? or maybe i should find something digital? i would like to keep an eye on my voltage thru my rides if possible.

 

[Kevlarr]

It would work you would have to be able to isolate it with a switch otherwise it'll draw off the battery when you're not running. Maybe put it in between the headlight and your switch.
If you wanted to go fancy you could set up an ignition switch (double pole single throw) and hook your blue wire to one leg and the volt meter connected to the battery on the other so whenever you're riding you can see your battery voltage that way you'd never forget and leave it on.

 

[Scotchmo]

i found a 6 volt analog volt meter i would like to use in the charging circuit,is this possible? or maybe i should find something digital? i would like to keep an eye on my voltage thru my rides if possible.

The analog voltmeter will work. And it might be the best solution for permanently mounting on the bike. I prefer a digital meter while debugging the system. Each has advantages. Here are some off the top of my head:

Analog meter:
Plus – looks better.
Plus - No secondary power source required.
Plus - Easy to read at a glance, can have a “red zone”.
Minus – full scale voltmeters do not give very fine readings.

Digital meter:
Plus – gives finer readings over whole range.
Plus – cheap meters available.
Minus – looks wrong mounted on bike.
Minus – usually requires a secondary power source (i.e. 9v battery)