Hitchcocks Forum

Im just putting LED lights on my Model G that will run direct off a 12V / 4 AH battery. the wattage of all the LED lamps together is 11 (10.5w headlight / .25w for both brake and tail lights ) so the current works out at .92 amps, unless I've made a mistake! do I need a to use a 1 amp fuse? or build in some margin? thanks

Usual to leave a margin. I would think 1.5a. The fuse is there to protect the wiring so unless you have replaced it with something very small it will easily stand 1.5a. You could happily leave the original fuse in place.

If I'm thinking right this is for a stand alone lighting system nothing to do with the charging system

In this case I would run from the positive side of the battery 2.5amp fuse then up to a light switch from light switch run to the headlight and tail light
The negative side I would run back to the battery from both headlight and tail ligjt and avoid the use of a earth

The stop light you will only need one so I would fit a rear stop light switch taking power from the fuse, or tap into the power to your light switch, then run the other side of the switch to the stop light then again back to the battery for the negative connection

You will probably want a hidden switch in the battery to fuse wire just to stop someone turning on the lights and flattening the battery

Hope this helps Dai

Just thinking I have probably made this sound far more complicated than it is

Daiwiskers wrote: ↑

Fri Jun 05, 2020 9:08 pm

In this case I would run from the positive side of the battery 2.5amp fuse then up to a light switch from light switch run to the headlight and tail light
The negative side I would run back to the battery from both headlight and tail ligjt and avoid the use of a earth

I assume you mean from the bike side of the fuse, not the positive side, the side between fuse and battery... if you did this, any short in the lighting could burn wiring, short battery or worse.


John

I assume you mean from the bike side of the fuse, not the positive side, the side between fuse and battery... if you did this, any short in the lighting could burn wiring, short battery or worse.


John
[/quote]

Hi John

I was describing a stand alone lighting system
The reason for running return wiring is to keep it totally separate from the bike

For some reason I don't think LED's will play well with a magdyno or magneto system (I could well be wrong there)

The big problem with a stand alone lighting system is the same as a total loss oil system

You have to keep both topped up !

I think Paul Goff may have some positive earth led's if Mart decides to run a charging system these may be the answer

Hope this helps
Keep safe all Dai

No worries Dai. I’d still stick fuse somewhere; no rude replies!



John

Put fuse between battery and switch

No rude replies

Positive earth LEDs will also work with negative earth. Negative earth LEDs won't normally run with positive earth.

If I do insulated earth return, I also loop it to the frame earth. The electricity will chose the path of least resistance.

The fuse size is determined by the thickness of the wire, not the load on the circuit, the fuse should be slightly lower than the current capacity of the wire. The thickness of the wire is in turn determined by the anticipated load on the circuit, the wire capacity should be higher than the anticipated load.

I get all my LED bulbs from classiccarleds.co.uk they have a good selection of positive earth ones too. 6 and 12v.

thanks for the input.