LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /
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Here is an inexpensive way to make an LED conversion on almost any moped , scooter or motorcycle. Any decent H7 LED lamp can be used although depending on your AC voltage , a 6 volt lamp may be brighter. The 50A 1000v diode bridge rectifiers can be had almost anywhere for $2 . The diagrams show the AC input and the DC output to the light . This means less or no pulsing with voltage changes and the lamps will not blow out with voltage surges. You can also put a capacitor on the DC side with a diode across the terminals too to prevent voltage spikes , but I have not found it necessary for most applications.

This can also be done for the tail light or even both lights if you find a place to mount the rectifier near the stator. AC in - DC out .Just remember the the terminal turned differently is the DC positive and the pair of terminals are across (kitty corner) from each other.

I just finished this conversion on a broken sealed beam lamp . The lens was broken and I used an old headlight to cut the new lens and fit it in place. That is for another thread.

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Re: LED headlamp conversion pictorial- bridge rectifier made easy.

That looks like an easy add-on. Does the rectifier not need a heat sink? It was my understanding that they can get pretty hot.

Maybe not an issue with a 50A one running a single LED?

I would really like to try this at the stator and just have all lights on DC. Started to research it and got too involved with other stuff.

Thanks for the post.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

🇮🇹💦 Of the Loin /

I love these radio shack rectifiers, perfect for moped stuff and basically indestructible

One caveat: if you are seeing let's say 14v AC when running at speed, that means you are going to possibly see up to 14v x 1.414 = 19.6v DC

So just remember that when designing the rest of the circuit

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /

There are 2 easy solutions for that . Start with a 12 volt lamp , which will take a lot higher voltage than 14.4 or go with the capacitor setup.

The 12 volt LED lamps are cheaper too.

I have now done 3 of these conversions with no issues at all.

It sure beats trying to replace sealed beam headlights at $25-$50 a pop.

I may try to mount the rectifier near the stator so the tail light will be LED also .

If i change it , i will post more pictures.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Oh man, El Pollo would be all over this!

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

> Ryan Graeme Wrote:

> -------------------------------------------------------

> Oh man, El Pollo would be all over this!

Yeah I was thinking the same thing, need him to come in here with half assed electrical knowledge and incorrectly criticize this post lol

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Dave Thacker /

I have been thinking of changing over to Tomos Revival regulator to also have a properly sounding horn. Whole thing DC. Add a capacitor to eliminate idle flicker.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /

el pollo , I forgot about all that nonsense .

It took me a long time to learn how to do this a simple way that i could explain it to other people .

It clicked the first time I did the LED headlight lamp on a ct-90 and didn't need the rectifier because the bike already has one to support the battery turn signals.

Basically , it was already DC.

Its easy, AC in DC out .

The capacitor is there to prevent voltage spikes and a diode to prevent return electricity spikes.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Mark Younggren /

Love this. Finally a straightforward post with out all the opinions and nonsense.

Dan would you be able to post some purchase links to the specific items you purchased? Yes, I know common electrical things but it helps in streamlining the process without any question

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

🇮🇹💦 Of the Loin /

I throw a voltage regulator and a capacitor on after the rectifier because the power is cleaner, if I wanna USB charge my phone for example you need a voltage regulator.

But yeah a lot of small Honda's are different electrical systems than a moped generally.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /

Here is the rectifier. I can't find the lamps right now. The one I used was from a previous order.

https://www.ebay.com/itm/2x-50A-1000V-Metal-Case-Single-Phases-Diode-Bridge-Rectifier-KBPC5010-BPHH/303636999659

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

I think I said something similar in another thread, a while back, about doing this same thing.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /

Have you done the conversion ?

We started doing them with sealed beams and those dumb festoon lamps .

We would break out the old lamp, drill the metal a bit to fit the new lamp, and put a slimmer regular or halogen lamp in to save $20-$50 on a sealed beam and make the lamp replaceable .

Those Honda motorcycle headlights are expensive.

Some times you have to epoxy the new lamp and socket in . .

Depends on the lamp you buy or get from the junk yard. .

Once we got a few under our belts , the led prices started coming down , making it worth while.

I am trying to make this as simple as I can so the average guy can do this for about $10 and all they need are a few easy to obtain parts .

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Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Ac is one wire and other is ground or is the ac "floated"

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /

At some point all the ac goes back to one chassis common point .

There is never a true grounded system on a wheeled vehicle , but if i understand your question , it is not floated.

Why would this matter?

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

🇮🇹💦 Of the Loin /

He's asking because you need to float one of them.

I float the DC side since the frame is already a sink for the backside of the ignition coil wave

Usually on motorcycles you don't have to care since either the AC is floated or it's center tapped

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Double Trouble Dan /

Now i understand .

In this case DC is floated although I'm still not sure why it matters.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

🇮🇹💦 Of the Loin /

You can bond them both together, but there will be noise on the line.

Incandescent bulbs don't care, and the LEDs that can tolerate AC from the auto parts store don't usually care either.

But if you want to charge your phone with a 12v-5v converter, or run LEDs you need to keep them seperate

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Well we're back on the argument of floating and not floating sorry if I introduced it I'm thinking that this silicon rectifier right at the very end of the line for a single light maybe that behaves differently than what happened to me when I tried to get good clear DC without having to wire AC basically using the frame ground as the back half of the AC with the silicon rectifier I couldn't really get much in the way of DC and when I took the back side of the light coil floated off the grounding and use that on a silica rectifier I found that my measured DC was just better way better I mean a whole lot better I mean like night and day basically so I don't know what I was doing that makes me such a you know always asking if you floated it and I have a feeling that this last step just before the light bulb maybe that's why it works so nicely

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

> Marc Friedman Wrote:

> -------------------------------------------------------

> Well we're back on the argument of floating and not floating sorry if I

> introduced it I'm thinking that this silicon rectifier right at the very

> end of the line for a single light maybe that behaves differently than

> what happened to me when I tried to get good clear DC without having to

> wire AC basically using the frame ground as the back half of the AC with

> the silicon rectifier I couldn't really get much in the way of DC and

> when I took the back side of the light coil floated off the grounding

> and use that on a silica rectifier I found that my measured DC was just

> better way better I mean a whole lot better I mean like night and day

> basically so I don't know what I was doing that makes me such a you know

> always asking if you floated it and I have a feeling that this last step

> just before the light bulb maybe that's why it works so nicely

No punctuation . BS . :(

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Per Kristian Sørpebøl /

I bought a Shindengen FH020AA, stable voltage 12.5V on idle and enough to charge the battery when driving :)

Costs a bit more but it's definitely worth it.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Pd: one ac wire off stator plus a ground gave poor quality DC off the silicon rectifier. Both sides of ac light coil gave me way better DC . That's my experience. My understanding is that it's twice the output.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

> Marc Friedman Wrote:

> -------------------------------------------------------

> Pd: one ac wire off stator plus a ground gave poor quality DC off the

> silicon rectifier. Both sides of ac light coil gave me way better DC .

> That's my experience. My understanding is that it's twice the output.

Thanks for that^ . Much better . :)

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

🇮🇹💦 Of the Loin /

I think you just had a bad ground.

fWIW I always make a new ground for my rectifier setup straight to the motor itself. No point in trusting the frame

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Hi there. I'm hoping someone can help me understand better. I'm looking to keep the stock headlight on my 1979 Motobecane 50V (12 volt), but add a 12v DC aftermarket LED taillight/brake light since my original is pretty much destroyed.

In the existing AC circuit, does power come off the stator and complete the circuit through the "ground". If I introduce a rectifier, am I interrupting that feed from the stator at the rectifier and return to ground? Then DC positive to lamp, DC negative to ground, or direct to negative on lamp, or does it matter? Hopefully the attached marked up diagram will better illustrate my questions.

Motobecane12v_wiring_diagram rectifier wiring.png

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

If u just want a rear led use a couple of diodes. I've got a bunch of them at home.. pm me your address and I'll mail u some on 12/18 when I'm back home. The diodes go between the power wire to taillight and a led bulb... Does the taillight have separate bulbs for brake and running light?

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

> Marc Friedman Wrote:

> -------------------------------------------------------

> If u just want a rear led use a couple of diodes. I've got a bunch of

> them at home.. pm me your address and I'll mail u some on 12/18 when I'm

> back home. The diodes go between the power wire to taillight and a led

> bulb... Does the taillight have separate bulbs for brake and running

> light?

Thanks , man! I'll keep that in mind. Existing is a single lamp with two filaments - running light, and brake light. The replacement is a cluster of LEDs with one wire for running, one for brake, one for ground.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Need two sets of diodes ...I think... There are numerous posts on this solution. I've completely regulated and rectified my bikes with "floated " ac ( use both wires ) but unnecessary for what you want to do.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

I got two rectifiers installed, one for tail running light, and one for the brake light. AC white and violet from stator to each rectifier, then to the chassis. DC positive from each respective rectifier to taillight wire and brake light wire. DC negative direct to the taillight. The system seems to work just fine.

Re: LED headlamp conversion pictorial- bridge rectifier made easy.

Dirty30 Dillon /

Your wiring schematic is all loopy. You don't need two rectifiers, especially not running against each other.

Just rectify power before the switch.

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