Home Made Rectifier

[Sgt. Hobo]

Can anyone tell me how to make a homemade rectifier that converts ac to 6v dc?

[WavyGravy]

the rectifier only converts ac to dc
look here for examples
https://www.allaboutcircuits.com/vol_3/chpt_3/4.html

you will need to follow this with a regulator chip to maintain voltage at 6v and mount its tab on a big heatsink (excess voltage is converted to heat)

Look up ohms law and work out how much current your lighs/indicators/horn/anything else will draw when all on and add a safety margin to calculate which diodes and IC regulator chip you will need - Maplins should be able to supply the bits
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1975 CB125s, 1991 GN250, 1990 Ducati Paso 906
"Don't wake him up - He's got insomnia - He's trying to sleep it off"

[WavyGravy]

just saw your other thread where stinkwheel was helping, I was in USA 2 weeks ago and your auto stores are huge and have just about everything! surely theyve got 6v rectifiers! .... as yours has 3 connections it will be a similar arrangement (i would think) to a 70's honda CG before it went posh and had 3 charging coils in the alternator. likely that the 2 charging wires will be the same colour and the odd wire will be the output.

I'd take your rectifier into your auto parts store and ask the guy behind the counter for something similar .... you'll probably find it'll take him 2 minutes and it might be a part from a lawnmower or ATV skisledge kids 4 track or any of those wonderful toys you lucky lot seem to spend half your life on!
____________________
1975 CB125s, 1991 GN250, 1990 Ducati Paso 906
"Don't wake him up - He's got insomnia - He's trying to sleep it off"

[finpos]

Checkout websites that supply stuff to the lambretta crowd - you'll find a 6V regulator there.

You have to be really careful making home-mode bike electronics - bikes/cars tend to put huge surges through the wiring when the engine starts or stops, so any electronic gubbins need to be well protected.

finpos.

[stinkwheel]

What you want ideally is an old 'superdream type' honda regulator rectifier unit (does it all in one). Your system has a rectifier that converts the AC to DC and a seperate regulator that maintains the voltage at 6v by dumping excess to earth. A combined reg/rec unit takes the AC alternator output and converts it straight to 6V DC.

They did make 6V ones. These units are almost infallible and will cope with even the shittiest charging system.

If you can't find a Honda one, any SIX LEAD 6v reg/rec will do but the wire colours may be different. To give you an idea, a BRAND NEW genuine honda 6v reg/rec costs £29 in the UK.

They were fitted to many small capacity hondas in the early 80's so you could well find on in a breakers yard. Some companies do make pattern ones too. Ask for a "six lead, 6v honda reg/rec". They should give you something that looks exactly like this (about 4"x4") with three yellow wires, a red, a green and a white on black:
https://www.te-motorcyclespares.co.uk/images/715915.jpg

How to fit it:

Disconnect the current rectifier. Disconnect the current regulator.

Look at the wires that went into the old rectifier. There are usually three (sometimes two) that come from the alternator and one that runs to the battery of the bike. You need the wires coming up from the alternator (they will be the ones running up from the engine itself, usually on the left side of the bike)

Connect these wires to the yellow wires on the honda reg/rec (doesn't matter which, if you have one left over, just tape it up).

Connect the red wire on the honda reg/rec to the battery positive.

Connect the green wire on the honda reg/rec to earth (either the battery negative or to the frame).

Connect the black wire with the white tracer on the honda reg/rec to any wire that normally has a constant 6V when the ignition is on. In your case, I'd use the wire that was previously connected to the 'stanley regulator'. If you are struggling, just connect it to the battery positive, it will still work like this.

Hey presto, assuming your alternator works, you now have a functioning charging system.