Secondary magneto coil for lights/acc?

[xenodius]

Saw this ebay auction: http://www.ebay.com/itm/12-VOLTS-MI...087?pt=LH_DefaultDomain_0&hash=item5d2856c29f

Anyone installed a secondary coil like this one? Couldn't find any posts about it in search, but I like this method of avoiding the white wire. I have a 12v/500ma front-wheel dynamo I could use, but I'd like to have power at idle. And, with that output, I could get 300-500 lumens from a couple CREE's!

Is it really as simple as building another coil and installing it in the magneto case?

PS: It'd be fun to get a mount and USB charger to make a dock for my phone for navigation/speedometer purposes! =)

 

[Harold_B]

I'd be interested in additional feedback as well. I bought the "Mini-generator/Charger Combo". The intention is to install it and a 12vdc lead acid battery from McMaster-Carr

 

[Harold_B]

I'd be interested in additional feedback as well. I bought the "Mini-generator/Charger Combo". The intention is to install it and a 12vdc lead acid battery from McMaster-Carr

Man, me and my fat fingers. The text entry area is right next to he "send" icon on this app. Not the first time I've posted a partial sentence. Anyway, I'll be connecting the battery to power a LED headlight, a tail light, a brake light, and a horn. All SoS requirements in MI. Also have a Stewart-Warner ammeter to monitor the system. Been thinking about turn signals and fog/driving lights as well. I should have it done by the end of the weekend so if nothing else I can give my two cents then.

 

[BigBlue]

xenodius,

Here's a post from someone who installed:
http://motorbicycling.com/showthread.php?t=35871

Just FYI, the Ebay listing states that it produces just over 12 volts at 1300 - 1500 rpm - driving speeds of 15 to 18 mp/h. So your not going to get 12 volts at idle as you wished in your OP.

Good Luck,

Chris
AKA: BigBlue

 

[xenodius]

Yeah, I saw that... I don't really expect full power all the time. But the regulator I'm using has a dimmer circuit... and I can always turn up the idle. Even if it was 1/2 or 1/3rd as bright at idle, I'd be a happy camper. I just don't want to be plunged into complete darkness every time I stop moving!

After I replace/fix my clutch, I'll consider wiring a second coil. =)

 

[Harold_B]

Pardon the pun but I'm in the dark on wiring a second coil. There's room for another coil or are you referring to using the secondary coil from eBay and the white wire too?

I was concerned about having the lights fade at slow speeds since that would be when I'd have the most drain (headlight, tail light and likely the brake light as well). That is why I went with a battery and using the system as a charger. Perhaps I'll end up adding a voltmeter to monitor the battery charge too. Sun set comes early in the fall in Michigan and I want to ride until the snow flies.

 

[xenodius]

I'm talking about winding my own coil like the secondary one on the ebay auction, and using just that-- no white wire. That coil is not $45 of materials, I'd rather roll my own! =)

A battery would take care of that, but FWIW, the slowest I can idle on my HT is about 10mph. If you set up a dimmer circuit and reduce power to your headlight a little as your coil produces less, you shouldn't have an issue... definitely not... maybe?

 

[bigbutterbean]

Saw this ebay auction: http://www.ebay.com/itm/12-VOLTS-MI...087?pt=LH_DefaultDomain_0&hash=item5d2856c29f

Anyone installed a secondary coil like this one? Couldn't find any posts about it in search, but I like this method of avoiding the white wire. I have a 12v/500ma front-wheel dynamo I could use, but I'd like to have power at idle. And, with that output, I could get 300-500 lumens from a couple CREE's!

Is it really as simple as building another coil and installing it in the magneto case?

PS: It'd be fun to get a mount and USB charger to make a dock for my phone for navigation/speedometer purposes! =)

you have to realize something. you cant take just any light and hook it up to 12v. if its a 6v light, 12v will surely blow it. led's do have capacitors that enable them to handle a little extra voltage, but not double the voltage they are designed for. I have a 50 led headlight that is 6v i run off the white wire. another member here tried to use the same light with a 7.2v cordless drill battery and fried it. so just be aware of that.

 

[Harold_B]

Actually, no. LEDs don't have capacitors but perhaps a circuit that has LEDs in it does. An LED is a diode. The white wire or the add-in coil are unregulated sources so there's no telling what voltage or current you were feeding your light. The 7vdc charger on the other hand was likely 7 +/- a couple tenths of a volt. It will depend a great deal on the LED, or if there are several the circuit (strings of LEDs in series with those in parallel, or all in parallel, etc) how much it takes to blow them. Heat-sinking will make a big difference as well and is something to consider when you swap out LEDs. Run and charge circuits are not my thing but I do know a little about LEDs.

 

[xenodius]

BBB, I plan on using this regulator with this LED. Now, 1x LED is fine from the white wire. But I'd like a tail light and 3 of these LED's because I want my headlight to be beastly, because I don't want to get pancaked. I think ~500 lumens should prevent that.

Gasbike.com says that ideal idle speed for an HT motor is 1400 +- 100 RPM... dunno if that's true. But even if mine idles lower, I'll just up the idle speed a little bit while they're on. Just takes a couple seconds to adjust =)

 

[Harold_B]

Unless you overdrive the LEDs you will not get 500lm. http://www.cree.com/~/media/Files/C...dules/XLamp/Data and Binning/XLamp7090XRE.pdf

The 100% drive current rating for the XR-E is 350mA typical which should get you a minimum 80lm per LED in the P4 bin. You could overdrive them but then you'll really need to watch out for proper heat sinking and the lifetime will be reduced. I didn't check the specs on the regulator. Is it a current limiting or voltage limiting regulator? It will make a difference as far as keeping the light bright and from turning to toast. But the heat sink is still a question. Do you know how you are going to attach three of these things and dump the heat? My guess is that you'll be lucky to get about 200 lumens out the front of the light. Perhaps you should look at the Cree XM-L? If this is a retrofit, what about the optics?

 

[xenodius]

I based my 500 lumens off of this google result. With high RPMS, that doesn't seem too unreasonable based on

I have an unfocused chrome headlight case mounted to my headset already; it was intended for an incandescent bulb. I'm going to replace that mount, and I imagined using JB-weld to fix the star plate because, hey, why not? It has a relatively low heat capacity. I'd like to use solder, but I think I'd short it out. Either way, it's going to be mounted directly onto the chrome case, which should dissipate the head fairly well.

It's a current regulator, but I have a spare voltage regulator as well =)

If I wanted to spend more than 10$... I'd definitely get one of those flashlights =) But I won't even need a light until this winter when the sun sets at 4:30 PM.

 

[Harold_B]

I hope my intentions are coming across I just think you might be a little disappointed by the performance of your LED based light given the data from Cree. If the flashlight manufacturer is running the LEDs at 220% of the rated current (1A) and the LEDs were at the stated minimum for the P4 bin then the output at the LED would be about 530lm. For an output of 500lm the optics would need to be more than 94% efficient. Loss at each surface interface is 4 - 6% so not likely. If nothing else, look at the beam shots they have in the ad. Yuck.

You are likely to be underwhelmed by the beam quality of your light as well. You mention the light that you are retrofitting was for an incandescent bulb. The reflector for a bulb filament is designed completely different than the TIR optics shown for the flashlight. Also, star pattern MCPCBs are intended to be secured with screws to a flat surface with thermally conductive goop in between. The stuff used for computer processor chips works nice.

Really, I'm not trying to be negative or an argumentative jerk. Just trying to share when I can.

 

[xenodius]

No, you have good thoughts! I didn't even think about cooling. And I read the sheet, disappointing info-- thought I was quite surprised at the stated outputs. I wish I kept one of the many tubes of Arctic Silver 5 I had piled up from my tower-building days! =)

I'm not so concerned about getting great beam quality as I am concerned about being seen. Worst case, if I really don't like the beam, I have a smaller LED bike like I could retrofit inside the headlight case, so I keep the matching styling of the bike but get a tighter beam.

Absolute worst case, I'll buy a cheapo flashlight and mount that inside the headlight case. =)

 

[Harold_B]

Many tubes? I'd like to have those myself! Sounds like you have a plan. I'm anxious to learn how it turns out for you.

I retrofitted a NOS BSA headlight with an LED (engineering part - not on the retail market as yet). A little more than the $10 budget you are looking to keep but this iteration will have 450lm. The next LED to go in will have about 1200lm.

Good luck on your build!

 

[xenodius]

When I was too young to have a 'real' job, I mowed lawns and built people computers. =) I ended up with a whole closet of spare parts around tower #80, now they're sitting in a shed 500 miles away.

I may not do it right the first time, but I think I'll get something rigged up =) Off topic, my favorite DIY project was making a ~200mW 650nm laser from a DVD-burner diode and other parts =) I think the best use I've come up for that gadget-- besides popping balloons and lighting matches-- is to test the toastiness of toast by smoke-testing the air above the toaster! =D

That's an LED to be jealous of! Looks like it has a good home. I think for now I'll just settle for a few cheap ones... not that I have an alternative anyway! =)

 

[bigbutterbean]

lets put it this way. my current headlight is 150 lumen. i went on a test run the other night to get an idea for comparison to the new headlight im getting soon. I went down a pitch dark road where there were no lights of any kind. my top speed is between 25 and 30. my 150 lumen headlight was bright enough for me to feel 100% comfortable driving full speed down a dark road. it light the road in front of me very well, and reflected off street signs 150-200 feet away. I also have a brake light that is an old motorcycle turn signal I converted to led and runs on 4 aa batteries. I figure that the brake light isnt on constantly, only when i brake, so it doesnt need a self-sustaining power source. in fact, I have had the brake light for probably about 3 months now, and i havent changed batteries yet. but i digress. the main reason i am ordering the new headlight is for the built-in regulator. its two super-bright led's, and its 270 lumens. as I mentioned before, it has a built-in regulator. the ebay seller (wonderful creations) describes it as an amperage regulator, i dont know if that is different from any other regulator, but i know it protects the led's from being overloaded. i dont know much about electronics, so i find it convenient that this unit is pre-assembled and is also designed for use on motorized bicycles. the unit comes sealed for weather resistance and im betting also for vibration dampening. for $17 plus 5 for shipping, its not a bad deal for something custom made. and if 150 lumens is bright enough for my needs, then 270 lumens will be more than enough. i understand that some people may not think 270 lumens is enough brightness, but for me its plenty. if 150 lumens can light up a dark road and reflect off street signs 150-200 feet away, 270 lumens will be plenty.

 

[Scootmeister]

Xenodius and Harold B, maybe you can give me guidance with my LED delimna. Recently I installed a 12 volt Mini-Gen Max coil to my Chinagirl and wired the AC output to a full phase rectifier (a working unit from a Yamaha motorcycle). I connected my LED headlight, one small instrument light to my Whizzer speedo, and my Bell LED tail light to the DC output. When I start the engine, the LED Headlight burns like the sun, but the other two lights do not work. When I disconnected the headlight from the DC circuit and start the engine, the other two lights work fine. When I disconnect the DC line from the rectifier and patch in a nine volt transistor battery, all three lights work like they are supposed to. I don't know much about LEDs, but it seems that the LED headlight is pulling all of the amperage at the expense of the other lights. The Mini-Gen Max coil is rated at 1 amp or 10 watts, it seems like that should be plenty to run my setup. What am I missing?

 

[BigBlue]

Are you testing your setup at idle or full power? Per the Ebay listing, the Mini-gen doesn't produce 12 volts till 12 - 15 mph. 18 volts or more @ 1.5 amps is not reached till high speed? What ever that is.

From the Ebay listing:

The engine speed here is around 1300 to 1350 RPM which is just around driving speed.
Most riders will produce this voltage at a speed of around 15 to 18 MPH.
Higher voltages of around 18 or more is obtainable at much higher engine speeds, but 12 volts is specified as the average voltage.

Also, per the Ebay posting states not to rev of 3000 rpms more than 5 seconds or you'll blow your bulbs.

What is the voltage, amperage and wattage of the headlight? What are the voltage, amperage and wattage of your instrument light and tail light?

Normally, you connect the headlight to the A/C output on the rectifier/regulator. You could run the instrument bulb and tail light off the D/C battery, depending on how much they draw on the battery. My guess is that they draw more than what the generator is charging. It is not a good on the battery if you are drawing more than charging. Depending on your amperage of your tail light you may have to run it off the A/C.

I don't recommend you connect your headlight to the A/C till you know for sure it will not blow the LED bulb(s).

FYI, the rectifier converts the A/C voltage to D/C voltage and the regulator regulates the D/C voltage to around 12 volts for charging the battery. I assume your rectifier is also a regulator and that you know the pinout of your rectifier/ regulator.

I have a limited understanding of electronics and wiring. Maybe a more knowledgeable member can chime in.

Good Luck,

Chris
AKA: BigBlue

 

[Harold_B]

My first guess would be that the everything is wired in parallel (as it should be) but the headlight LED has a much lower resistance than the rest of the circuit. It's probably taking the full output of the mini-coil. Most headlight LEDs are 1W devices although they typically require less current than the 10 Amp max. More like 3-4 Amps. LEDs don't like AC so connecting it directly to the white wire is not likely a good idea. I'd love to be telling you I have my system working but I don't. I've been running it off the 12v battery directly until I can get the harness sorted out. It should be a matter of connecting a few wires but I want an ammeter and a volt meter in the circuit to monitor charge level. I see a similar effect to yours even off the battery since I'm not charing it as it runs. When I apply the brakes and the stop light goes on, the headlight dims quite a bit. If it were not on a battery but on a current limited circuit something wouldn't be on. Just my guess. I would think that if you want to run more than just a headlight and tail light and they are not well matched (like say an incandescent tail light and LED headlight) then you might want to consider adding a battery and charger circuit.