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AC - DC CONVERSION [CBF125 ]

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ac dc bridge rectifier convert honda led lights
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29K views 115 replies 7 participants last post by  DannoXYZ  
#3 ·
Your bottom diagram is a waste of wiring.. any and all loads can be drawn off the battery voltages supplied to the keyed ignition switch.

The red/white dotted line coming out of the rectifier is a 12v line. your system is 12v, all bikes use an AC to generate power, then has a R/R to rectify it to DC and then regulates it.

You can do one or the other:

Run a direct "fused" power wire lead from the battery with a seperate on and off switch, and then just attach a ground to the frame. (you need a switch to turn off in this method)

or:

Tap into the power wire coming "out" of the ignition switch (this wire is direct battery voltages) and then run a ground to the frame. this method gives you the key to turn off the added accessory.
 
#8 ·
Visualizer said:
I already have a switch taking power from the fusebox using a "fuse thief" to power my "fog lights" . If I connect everything to the battery it will put a lot of stress , already when I am stopped and I use the turn signals with the fog lights I can see the fog light dim a bit .
But the red and white is for the battery I want to change the original harness as little as possible thats why I am trying to do it like this .
Click to expand...

If you take directly from the R/R, you will limit the amount of power going to your battery.

So you take the power from the battery as every other bike in known existance does so you dont prevent your battery from being under charged. this will leave you stranded likely from a low power battery.
 
#15 · (Edited)
You still have not answered the type of led you have question.

the yellow wire is the factory AC lighting wire. yes its for lights, but this is a single phase AC altinator. which means when your rpm drops, so does the power voltage.

The better step up version of your system has a seperate lighting coil. yours uses the same power generated to run the lights and the charge to the battery.

Notice the lower right "alternator" it only has one wire (white) this is the "only" output it has, the green is ground.

So you either have to use low voltage AC leds, or you have to use the 12v side and run new wires.
 
#19 ·
Ok, look at the altinator in your diagram (top one)... the green is ground... the white is AC voltage that when tested will not excede on this single phase alternator 20vAC (max rpm)

You see the curly thing in the middle.. thats a "single phase" AC coil.
See on the bottom the ground (green wire) this is the ground for the alternator/ststor mount base.

Image



This green wire is shared by all componets in the system. (follow the wire from here and you will see it goes to all lights)
as well as the R/R. again this is a ground.
the white wire here is the "single" power output. (most bikes today have a 3 phase/ 3 wire)

Notice how this white wire stops at the R/R... Now here is where you need to confirm with a voltage test. the wellow coming off the R/R is some times "pass thru" AC, meaning it just passes thru the r/r un changed. This wire will only go to "some" lights, notice how the rear signals do not share this wire just the tail/brake.


Following me so far?
 
#22 · (Edited)
Ok, the yellow will most likely be AC voltage

the red/white coming out is the 12v DC


As you can see the system has both. this system is of the verry lowest power output they make. Meaning the AC power is just enough as needed (And) The12vDC is "just" enough " converted from the AC. the 12v output is dependent on the strength of the AC output.

If you trace the 12v and the Ac wires they both support different componets, and also supply the ECM.

Some sensors are 12vdc, some systems are AC. My point is these are highly dependent on the voltages they do get to function.

When you try to add a light, you effectivly lower the available power the entire system recieves.

The light you mention (H4) is an automotive bulb that will need more voltage than your system can provide. So with it not having all the power it needs, it will flicker, or not come on at all in some cases.


Most of these systems are so old that they were no longer used except for in mass produced "non manufacturer" clone engines. because they are a base system and cost effective. These on carburated bikes only ran the lights and ignition (CDI), and the 12v was what was used for the starting system.

Most people were able to replace the stator with a 3 phase, with 3 times the power output (up to 80vAC) and were successful in rewiring the rest of the replacement lights in.

Heres the problem for you.... yours is a FI system intertwined with this dual output system and has crank sensors, ECM's etc... meaning you cant just change the system as easily as you think.

Bottom line is until you have a larger amount of power from the alternator/stator you will not have sufficient power to run any accessories/ without pulling power from other componets.
 
#25 ·
Visualizer said:
By the way I found a video which I had it recorded .. here is the link if you want to watch https://photos.app.goo.gl/Szsf7D8ruQmDh93Q6

"If you trace the 12v and the Ac wires they both support different componets, and also supply the ECM. "

I dont see the yellow wire to go to those sensors.I am missing something here?
View attachment 70196


"
When you try to add a light, you effectivly lower the available power the entire system recieves.
The light you mention (H4) is an automotive bulb that will need more voltage than your system can provide. So with it not having all the power it needs, it will flicker, or not come on at all in some cases. "

I am not trying to add more lights but just replace the existing one's with LED which consume less power.I only want to change the lights to DC not all the system.
So you think the modification diagram I uploaded on my first post wont work?
Click to expand...

I just looked back at some old diagrams I have, thes sometimes were a 12v output as well, and yours is as well, its not an AC lighting system. The whole system is 12v. Lighting included

proven here:

Image



The whole system is12v, just has a seperate lighting circuit.
 
#27 ·
The older chinese scooters had some with an AC lighting circuit same as this, but also some others had the same sytem with a 12vdc out lighting circuit. I honestly thought all these were done away with.
 
#33 ·
I said this already... your stator is a single phase, and does not produce enough power to run anything larger than whats already in the bulb sockets. you can easily look the bulb numbers up and then search for the equivilant in an led format.

But keep in mind your signals will flash extremly fast.
 
#43 · (Edited)
Visualizer said:
View attachment 70201
By the way I believe the ECM is powered from the battery through fuse B .. So I dont see any AC sensors.
Click to expand...


the part I already told you... see the "single" white wire coming off the stator?????

that is the only thing providing any power at all..you get roughly 20 to 28vac per white wire. you have only one. most other bikes have three, the three ca produce 3 time the power your can.

So again.... yours does not produce ENOUGH power to alter anything on the system.

the only way to acheave more power is to upgrade the stator and R/R to a 3 phase system.

This is for the CBR 125, it may bolt right in, with minimal wiring changes.


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Note the three yellow wires (three phase).
if you get this make sure the outer diameter is the same as your old one.
 
#44 ·
Visualizer said:
"I just looked back at some old diagrams I have, thes sometimes were a 12v output as well, and yours is as well, its not an AC lighting system. The whole system is 12v. Lighting included "

12V DC? if so how we can explain that I get 12V AC at the lights?
check this please New video by chris cs

View attachment 70202
Click to expand...

For one you always set your meter to the closest setting to the voltage your measuring. In your video, you have it set to 200, when it clearly should be set on the 20.

when you test AC voltages on a DC circuit at 200, the voltage will give a reading, nad as voltage increases the reading will decreas. You are seeing a confliction of the wrong test setting in the wrong voltage type and also the inner resistors of the testor giving you a false reading.


Set the meter to 20v DC, and re test. voltages will increase as rpm increases.
 
#50 ·
Visualizer said:
The white wire goes to honda's regulator and gets converted and regulated to DC to charge the battery . The battery through FUSE B provides DC to ECM at IGN input. No?
By the way I took the idea from this guy
Click to expand...
Do you know what a capacitor is??

it is a power "storage" bank similar to a battery, however a capacitor unlike a battery will discharge "ALL" of its stored power at once. Where as a battery will only discharge its power at set levels of voltage and oner a length of time.



This guy all he did was ad another rectifier at the headlight, this only rectifies the headlight ac on his to dc for his new light, and he used a "high charge high discharg" capacitor to stabilize the current to prevent flicker.

If you have a "how to" from him, why are we discussing this?
 
#52 ·
Visualizer said:
Yes I bought one but I am not planning to use it since the boost buck convert has one in it ..thats the way how it keep the voltage stable to 12v I guess
Click to expand...

I have already told you these systems came in an AC and a DC mix, but also had an DC only system. your lights on your diagram say they are a 12v 35watt.

Post a picture of your headlight and box
 
#54 ·
Visualizer said:
Headlight bulb? hmm what box you are reffering ? sorry I dont understand
Click to expand...

The picture in post #25 is from your wiring diagram.

and I will post it here as well.

It says your headlight is a 12v bulb with a 35watt high beam and a 35watt low beam
Blue wire is the high beam, and the white is the low beam then the green is the ground wire.
Image



Look at your diagram for the tail/brake lights, it still says 12v
 
#62 ·
A buck converter is a DC to DC "step down" converter, meaning when you install the buck converter it is reducing the voltage you are already giving it. :ROFLMAO:
 
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