Fitting LED lights

[Dell]

Hi, I would like to fit LED lamps to my ‘59 AJS 16. As I understand it, I need to remove the AC feed to the switch leaving a rectified DC feed to charge the battery. I am aware this will disable the emergency start facility which I can live with. LEDs will not work with AC. All three wires from the alternator are fitted to a solid state rectifier with one DC feed output. Any thoughts on where to attach the rectified feed for best results?
The total load from all lights, side, head, and tail is only 2.4 amps. The bike is still on 6v.
Any thoughts, advice greatfully received. Regards, Dell.

[Expat]

Hi Derek, not sure if it applies to your bike but on my ‘60 Matchless G3, I just did a straight swap to LED lamps throughout with no further changes and all seems fine.
Hope this helps. Steve

[Dell]

Thanks for your input. No problem until I start the engine, then the lights flicker. I presume this is because the alternator supplies current to the lighting circuits when running? Dell.

[Reynard24]

How have you connected the rectifier? All the solid state 4 terminal rectifiers I have ever seen have two AC input terminals and two DC output (+ve and -ve) terminals with the positive output normally identified.

[g80csp11]

If you are running a rectifier /regulator unit that control to 6V in your case and it has 2 yellow wires as AC input and red and black DC output , then normally you would do this

Start with the alternator wiring, where a 3 wire 6V, stator is being converted for use with this new electronic unit
The green/yellow and green/black wires are first joined to give a single connection to the rectifier unit AC input (Yellow)
The green and white wire is connected to the other AC input (Yellow)
The DC output red is positive , and black negative
Assuming positive earth the red goes to a frame earth , and the black connected to the original loom power ( usually feeds to Ammeter )

by doing this the Emergency switch position is not used

Does this tie up to the instructions you received with the new rectifier/regulator unit ?
Check and understand before just changing your wiring
what make of rectifier have you fitted , instructions are usually available online

[Expat]

Interesting. That probably explains why the headlight main beam flickers on mine when bike is ticking over though it does work ok at normal speeds, dipped beam and indicators too. I had assumed the flickering was due to insufficient power being supplied.
I will get around to checking the wiring and instructions supplied, if I can find them!

[Trefor]

Dell, you do have an electronic regulator or just a solid state rectifier? If the former ( the preferred option) is fitted the charging system should work without any hitches, as mine does with a AGM battery and LED lights. If it's just a rectifier the regulation of the system is governed by load and probably is not amenable to modern bulbs and batteries.

[Groily]

. . . If it's just a rectifier the regulation of the system is governed by load and probably is not amenable . . . etc

I think that is right, because cutting in additional alternator coils just to support LEDs that draw almost no current / consume negligible power would suggest the battery might get overcharged.
Early alternator systems were designed to run with traditional bulbs (like 30/24W or maybe 36/36W, needing 5 or 6 amps at 6v). These bulbs would have used most of the additional alternator output so the battery didn't get blasted.
Things all worked quite well, within their limits, when early alternators were rated at a modest 60W. Batteries weren't boiled too often.

You could stick with old-fashioned bulbs though - if you have only got a simple rectifier ? ? ?
While I'd personally always use a combined regulator/rectifier for better voltage control and for simpler wiring, there's nothing wrong with old- fashioned bulbs and I've retained them on my own alternator bikes (I nowadays use LEDs with dynamos). Because alternators generate simply according to their speed of rotation you have the juice freely available and might as well use it (well, that's my logic). They aren't 'intelligent' devices like dynamos or field-controlled modern alternators and it makes little or no odds to their lifespan whether you apply loads or don't. They are also very reliable - as long as the primary chain is kept at bay!