Wiring up two headlamps to single dynamo

[Christophe]

Just fitted a rather natty Nitto mini rack which has light brackets on both sides and have installed a Cyo which looks pretty good.

I have a spare Cyo also so thinking about twin headlights. Can I just hook up the 2nd light to the spade connectors coming out of the back of the first light or is there more to it? Also will the hub generate enough to power both lights to a decent level?

Hub is a Shimano XT 3W /6V

Also if you start talking about wiring in parallel and series you'll have to explain what that means as I am a bit of a luddite when it comes to anything electrical.

Cheers

Chris

[Brucey]

wire them in series (if you ride reasonably  fast) and enjoy more light except at very low speeds or wire them in parallel (if you only ride slow) and don't get much (if any) more light.

For series connection run all four wires to the hub, and connect two together (not from the same light obviously) and connect the remaining pair to the hub.

cheers

[andrew_s]

Series is probably best, in that you will get more light when going fast.
Going slower, or with parallel wiring, the advantage of 2 lights isn't that you've got more light, but that you've more control of where the light goes - eg avoiding wheel shadows.

Parallel wiring is where you connect both live (black) wires to one hub terminal, and both earth (black & white) wires to the other.
The spade connectors on the Cyo are intended for a rear light.

[Kim]

If you've already got the bits, suck it and see what works best: parallel, series, or just one lamp.

The main reason for doing this that I can see is that it allows you to spread the light differently - as andrew_s says, to avoid shadows, or to provide better nearfield illumination.  A mere doubling in intensity isn't going to make much of a difference to the perceived level of illumination if you aim them at the same point.

My gut instinct says this will compromise your low-speed illumination for a little more brightness at high speed, and that that's probably an own-goal if you ever ride on anything that's not smooth clear tarmac.

No idea if daisy-chaining through the rear light output would work, but it would effectively be a parallel connection.

[SA_SA_SA_SA]

I have a vague memory schmidt thought series vs Parallel mattered much  less for higher end  Led LAMPS like their Edeluxes (and thus the Cyos which have the same electronics) and parallel is simply for the rear lamp (also you could also make one switchable if low speed is a problem)...

I think it used to be on their own website but I cannot find it,,,,