6 Volt LED headlamp w/ small 6 volt motorcycle battery

[Scotchmo]

That is exactly how I have it wired...
The only marking on the rectifier is a "+" on one of the poles. I imagined this to be the AC "in".

That is wrong. The "+" is always the positive DC output.

You better test the bridge because you may have blown at least two of the internal diodes by running it that way. Why don’t you just use a single rectifier diode? It is much simpler. The full wave bridge can work but you need to learn a little more about AC voltage and rectifiers before attempting it. You can learn from trial and error, so keep trying.

 

[BrettMavriK]

Scotchmo,
when you are right you are right! =-]'
I have it wired wrong.

After finding the package to look again at the schematic,
the only positive marking on the rectifier goes to the DC +
and NOT the AC+ like I have it. Now it makes sense.
It would not matter on the AC wires which one is negative or positive
as it is alternating. Adoy!

That's how I melted the first rectifier. I had it backwards.
So just in case, I bought a new rectifier and the zener you recommended.
I will rewire the system and try it again. I'll take out that other one-way
diode as well as to get full wave rectification from the Mini-Gen. I recoated
the mini-Gen with thick black paint just to make sure this is
not a compound of the problem.

One question:
When I wire the DC - from the rectifier to the battery,
I also bring it to engine ground as well, no?

You guys are gonna make an electronics novice out of me yet! =-]'

 

[Kevlarr]

If you have the clearance for it Plasti-Dip makes an excellent insulator. It's vibration and moisture proof too.

 

[Scotchmo]

Scotchmo,
...
One question:
When I wire the DC - from the rectifier to the battery,
I also bring it to engine ground as well, no?

You guys are gonna make an electronics novice out of me yet! =-]'

No. That would only work if you were doing a half wave negative ground system (the one that I usually recommend). Your MIN-GEN has a motor ground which puts AC to the motor and chassis. Since you are attempting to implement a full wave rectifier, you must keep everything on the DC side isolated from the motor and chassis. That includes both battery poles and all light connections.

The half wave negative ground system lets only the positive half of the AC wave to the battery +. The negative half of the wave is filtered out by the diode, so you can ground the battery negative and any other components that you want to. The full wave system effectively “swaps” the leads to the battery when presented with the negative half of the sine wave and therefore charges the battery using both halves of the sine wave. Unfortunately, if your battery, lights, or any other component in the system is grounded, it is also connected to the grounded AC signal from the MINI-GEN that has been “swapped” to the battery +. You now have a short from the battery + to the battery -. That may be a little hard to follow but it’s the best non-technical explanation that I could come up with.

 

[BrettMavriK]

Kewl, because I never grounded the battery's neg wire.

Okay,
So I corrected the rectifier and put the Mini-Gen back in.
and nothing....no spark.
Take the Mini-Gen out, and she fires within a quarter crank of the pedal.

Yesterday was a big fluke as to why it worked.
I had it wrong anyways, so the Mini-Gen was never working?
But why then was it running fine, THEN quit all of the sudden
to the outcome I now have?
Perplexing.
The lights never lost there intensity, so I figured it was working.
Then it just died. I took the Mini-Gen out this morning and changed nothing else,
and she fired split second. So maybe somehow it was working and
then something somewhere changed.

So,
it's plan B now as the Mini-Gen doesn't play well with the Magneto
when it is fully rectified.
So, should I ditch the full bridge rectifier and
throw in a diode for 1/2 wave and keep the Mini-Gen?
Do I then ground the battery negative to the engine?

Or should I pitch the Mini-Gen and go with the white wire and a diode?

Decisions, decisions....

 

[Kevlarr]

Will it run with the mini-gen connected to ground and not anything else?
Will it run with the mini-gen connected to ground and a load like an incandescent bulb?

 

[BrettMavriK]

Nada.
Nada.

It's one of two things:
1.The full bridge on the Mini-Gen messes up the Magneto's AC somehow.

(but why did it work Yesterday until it died, even though I had it wrong,
I had the diode in there for at least 1/2 wave.)

2. The Mini-Gen is now defective and is shorting everything out.

I'm going to remove the full bridge rectifier tonight and put a diode in it's place
off of the Mini-Gen's red wire and see if I can derive 1/2 wave dc from it.
If that doesn't work, I'm getting another Mini-Gen sent to test further,
and I'm going to diode the white wire off of the Magneto to charge the battery until
the new Mini-Gen comes in the mail.

I am not giving up on it just yet.....

Just had a brain belch:
If I can diode the Mini-Gen and get a half wave of DC power and still get spark,
and then also diode the white wire off of the Magneto as well, is it possible to
wire them both to the battery for more power?
They are both dioded off from each other so one
couldn't harm the other, no?

Just a thought....

 

[Scotchmo]

Nada.
Nada.

It's one of two things:
1.The full bridge on the Mini-Gen messes up the Magneto's AC somehow.

(but why did it work Yesterday until it died, even though I had it wrong,
I had the diode in there for at least 1/2 wave.)

2. The Mini-Gen is now defective and is shorting everything out.

I'm going to remove the full bridge rectifier tonight and put a diode in it's place
off of the Mini-Gen's red wire and see if I can derive 1/2 wave dc from it.
If that doesn't work, I'm getting another Mini-Gen sent to test further,
and I'm going to diode the white wire off of the Magneto to charge the battery until
the new Mini-Gen comes in the mail.

I am not giving up on it just yet.....

Just had a brain belch:
If I can diode the Mini-Gen and get a half wave of DC power and still get spark,
and then also diode the white wire off of the Magneto as well, is it possible to
wire them both to the battery for more power?
They are both dioded off from each other so one
couldn't harm the other, no?

Just a thought....

You answered nada to the first question from Kevlarr. I assume that means that the motor will not run when the MINI-GEN is bolted on but no wires are hooked to it. You need to make sure that the motor will run with the MINI-GEN in place and the MINI-GEN wires disconnected. If it won’t, then that is strange. Maybe there is some kind of internal short in the MINI-GEN that is causing a disturbance in the magnetic field of the magneto/CDI.

Putting a diode on the otherwise disconnected wire of MIN-GEN is not going to make the motor work. So how can you derive 1/2 wave DC from it?

Your idea about having two charging sources could work. But why complicate it. If the MINI-GEN is working, either full wave or as a half wave, you don’t really need to access the meager output of the white wire.

 

[BrettMavriK]

Update on the Mini-Gen

Well, the bike wouldn't fire with e Mini-Gen installed and wired to
the full bridge rectifier, but if I took it out the mag would send
the power to the CDI and it would fire right up.

So this time I left the Mini-Gen installed, but I cut the red wire going to
The one AC side of the rectifier; thus halting it's power.
Nothing....no spark.

Problem found.
The Mini-Gen has died inside and is shorting out the system.
That explains the intermittence of why the engine was stalling and
then finally would not restart.
The Mini-Gen was telling me it was on its' way out.

I have a new one on the way to test again now that my wiring is correct.

To be Continued.

 

[Scotchmo]

Update on the Mini-Gen

Well, the bike wouldn't fire with e Mini-Gen installed and wired to
the full bridge rectifier, but if I took it out the mag would send
the power to the CDI and it would fire right up.

So this time I left the Mini-Gen installed, but I cut the red wire going to
The one AC side of the rectifier; thus halting it's power.
Nothing....no spark.

Problem found.
The Mini-Gen has died inside and is shorting out the system.
That explains the intermittence of why the engine was stalling and
then finally would not restart.
The Mini-Gen was telling me it was on its' way out.

I have a new one on the way to test again now that my wiring is correct.

To be Continued.

If this true, it is very interesting. Most HT users have discovered that shorting the white wire will kill the motor. BrettMavrik has reported that a short in his MINI-GEN coil is disrupting his spark enough to cause the motor to run erratically or not at all. The blue wire alternator coil, the white wire coil, and the MINI-GEN red wire coil all share a common ground. Does this cause them to affect each other? I don’t know. It could be the magnetic fields affecting each other and maybe it would happen even if they did not share a common ground.

I recommend using a half wave, negative ground (½-gnd) rectifier system on the white wire to act as a battery charger. I do this because on my motor, using only the positive half of the white wire AC wave does not affect the spark. I’m guessing that the same may be true for the MIN-GEN red wire. Maybe that is why the company that makes the MINI-GEN only uses a half wave rectifier in their optional Mini-Charger. Maybe they really did research as they say. The ½-gnd that I outlined earlier in this thread may end up being the most appropriate system whether you use the white wire or the MINI-GEN red wire to charge the battery. The components that I specified should be adequate for either. If you set up the ½-gnd with the white wire, and find that you still need additional alternator output, you now have another option. You can just install the MINI-GEN and hookup the red wire in place of the white wire for increased alternator output. After BrettMavriks experience, we will still have to see what the consensus is on the quality and reliability of the MINI-GEN alternator coil.

If I had a MINI-GEN to test, I would short it to the motor to see if the motor dies. And if so, I would then run the shorted diode test, in both directions. Does it kill the motor when hooked up in one direction but does not affect the spark in the opposite direction? If so, then that would confirm that it has the same half wave limitations as the white wire, though hopefully it provides a much higher output.

 

[BrettMavriK]

Yeah,
what he said.... =-]'

In my case I have a bad Mini-Gen, as it kept the motor from firing
even with the red wire cut, but the unit installed on the magneto.
Definitely a short in it. I have a new one coming for further testing.
It worked for a while in half wave form we know.
Full wave remains to be seen.
When the new one comes in, I will do more complete testing of it's
voltage at various rpm's, the AC Magneto Kill Test, the DC Magneto Kill Test,
And see if I can truly get a full wave out of it in DC.

Here's some photos of the Mini-Gen

 

[Kevlarr]

If I pay postage is there any way you could send me the old one for dissection? I'd like to count the wraps and see the gauge of the wire.

I'm not entirely convinced that this isn't something that a person couldn't make themselves with rudimentary coil or motor winding skills.

 

[BrettMavriK]

I totally agree.
It is merely a stack of thin metal plates (maybe 11 ga.),
the 3rd from the top has the tangs to attach it cut out of it,
and then there are windings covered by what looks like hockey tape
with one wire coming out of it.

I think I may have to send this one back in the box that the new one
comes in. I'll probably know later today.

 

[BrettMavriK]

The replacement Mini-Gen shall be here tomorrow.
I'm going to try again for full wave dc rectification
to find out if will interfere with the Magneto or not.
It would be awesome if it works this way, but if not,
the half wave set up I know will work, and it will put
out more power than the Magneto's white wire.

 

[BrettMavriK]

Allrighty,
The replacement Mini-Gen came promptly.
Very good service is had from Nate at Wonderful Creations.
But then bad news Yesterday. I put the Mini-Gen in without
wiring it up to anything to see if the situation I had with the last one
didn't repeat. It did....
-Mini Gen attached but not wired up - No Fire
-Mini-Gen out - Fire
-Mini-Gen in and wired with one diode for half wave rectification DC - No Fire.

Perplexing.
So I wrote Nate back, explaining that maybe my stock magneto was faulty
and too sensitive for the Mini-Gen. Nate wrote me back and said in some rare instances
the waves aren't aligned between the two units and the CDI will act up. He then instructed
me to take the Mini-Gen's red wire and ground it out to the block when starting for the first time. He said this was perfectly okay to do and neutralizes the Mini-Gen's power. Then undo the ground to the red wire and measure the Mini-Gen's voltage. I haven't done this as of yet due to the message's late arrival Yesterday. I will attempt this here in a little bit. If it works, I'll let everyone know.

Could anyone explain the theory of this situation?
I have trouble wrapping my head around it.

 

[R$idgerunner]

"Bat" lurking here....Hi Ya'll...I have been researching "half wave / full wave" rectifier applications for a 37 year old Dirt bike..stumbled on to this and must say it has helped beyond belief!!!!...I like Ya'll!!..and your bikes!...I like to make little 50cc and up "Retro" crotch rocket Race Bikes...Live in the Mtns. Got a ques. for "Scotchmo" if I may be so rude???....The way I understand it.."Recftifier is Rectifier"...Right???...if wired right; the only reason for the little one's {Radio Shack sells} is weight and space per application???..with the exception of too much "Load" which "Over Heats" the unit ...burning it out or popping an internal diode??????????...I am kind of right there in my understanding of this...I have a DIOTECH - #DD3506 1"x1"x1/4' thick..metal casing, epoxy filled with stud or bolt hole in middle about 3/16"...looks a lot like "Old School" zeners off Brit Bikes with out the fins...$20.00..I got it from a country Elec. company that fixes elec motors and just about everything else..unfortunetly {My Keyboard sucks!} they have no idea about 2 wheel ANYTHING and it brings "Shudders" of Biblical nature to get anything approaching information....Diode"+" to Batt. "+" {fused to 10 amp}..Diodde Neg. to Batt. "-" ...Diode "A/C" in from Mag. .....Diode "AC" Out to "Lighting Systeem"...with the only catch being "Reversal of the "Diode A/C"s will change the "Polarity" of the Batt. input "Charge"??????????????????????????????????????????????????????????????????????????????????????????????????????????????....Pleaase HELP ME if I need to go "private with "Scotchmo" I am there!!!...didn't mean to inteerupt but living in the Mtns. you "Grap what can get"!!...I saw a Pic. of one of these "New Style" fandangled bicycles recently that a boy had painted and gillded white with letters, made a gas tank, and got some old bars...It looked just like an early 1900's Harley!!!..Having seen that I "Have To" build one..Again I didn't mean to offend.. buy playing "Bat"...M

 

[Junster]

So Brett, did you get this thing to work?

 

[Scotchmo]

Update - I have been running a 6v system with a small sealed lead acid battery. I ran it for 700 miles with the zener regulator and 200 miles without. It makes no difference. The ½ wave output with the white wire is too weak to hurt the battery. It just barely keeps the battery charged if you don’t run the headlight too often. It is suitable for a minimal 6v system. If you want something more powerful, I would definitely consider the 6v or newer 12v MiniGen sold on eBay.

 

[BrettMavriK]

My 3 watt cree l.e.d. headlight, and brake & tail light works awesome with the 6 volt lead acid battery.
I couldn't get that Mini-Gen to work on this motor. I tried a new CDI and a New Magneto, and
no go....

 

[jay sawdust]

aloha Brett...Yea...I gave up and got a batt. holder for 8 aa batteries from radio shack (that equals 12v).....Got a automotive stop tail lamp and a scooter brake lever w/brake swich....on the one bike i put this set-up on I just run a brake light hooked to both leads from the light.....the batteries have lasted for months......On my other bike i plan a headlight....brake ...and running lights with a swich for headlight and running lights.....perhaps spring for rechargeable batteries.....One thing i like about the aa pack of 8 is its so small you can put it most anywhere....under the seat?.....anyways take care all......J