SON Hub & B+M Micro Taillight: must be wired to the front light?

[Matthew Williams]

Hi everyone,

I have a SON dynamo front hub, with an Edelux II headlight. I was planning to get the  Busch + Muller “Micro” (µ) taillight:

https://www.bumm.de/de/produkte/dynamo-rucklichter/parent/332/produkt/332alk-silber-332alk-01-schwarz.html

Elsewhere, I read this particular taillight 

"The µ is designed to be powered from the front light only"

"This light must be wired to a front light, and should not be run directly off a dynamo hub”

I have several questions:

Is this setup inadvisable/poorly-considered?

Will the taillight sap power from the headlight?

Is the B+M Micro compatible with the Edelux II and SON hub?

Has anyone done this setup (SON hub, Edelux II, B+M Micro)? 

Does this setup require special customization?

What should I know before getting this taillight and setting it up?

As always, your sage advice, experience, wisdom, and recommendations are welcomed and appreciated.

[Brian Turner]

You should be good… Pretty sure that’s how most rear dynamo lights work… wired into the front light. Just read up on what connectors you’ll need if you plan on doing the wiring / soldering yourself.

On Mar 16, 2023, at 10:55 PM, Matthew Williams <matthewwil...@gmail.com> wrote:

Hi everyone,

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[lconley]

You need to wire the tail light from the headlight. If you do not, and you turn off the headlight, the tail light may burn out because it cannot absorb all the power of the generator. All modern LED headlights are designed to power the tail light through the head light and switch the tail light on and off with the headlight switch.

Back when headlights were incandescent, you could get 2.4W and 3W headlight bulbs (you still can) depending on whether you intended to run a tail light or not (tail lights were 0.6W). Whether or not the tail light is run through the headlight, the tail light still uses that power.

I have several SON hubs, an Edelux I, and Edelux II and several B&M headlights and tail lights. I wire all the tail lights through the headlights. The only combo I know of that has some issues is that the B&M Luxos U headlight has some compatibility issues with a few tail lights. The Edeluxes work with all the B&M tail lights.

The Edelux II has a tail light spade connection for the tail light wire. The Edelux tail light connection grounds to the headlight mount with a ring connector, it does not have a separate spade terminal.

Use dielectric grease on the connections (sometimes sold as "bulb grease" in auto parts stores). The connectors can be very, very tight and the grease helps putting the connections together as well as waterproofing them. Note that dielectric means insulating. The grease acts as an insulator, but the grease has such a low viscosity that it easily flows away and does not prevent the metal to metal electrical contact, what it does is prevent the connection from corroding. If the connectors are still too tight to put together, you can very slightly open up the female spade connector with a tiny screwdriver.

Laing

Delray Beach FL

[Bones]

It plugs right in. I think they are just trying to tell you not to run a taillight by itself, directly off of the dynamo. They are not designed to do that. I have several different dynamos with varying headlamp/taillight configurations and they all work the same: taillight plugs into the headlamp.

Regards,

Bones

On Thursday, March 16, 2023 at 10:55:30 PM UTC-4 Matthew Williams wrote:

[rlti...@gmail.com]

I have that tail light hooked up to an IQ-X headlight on our Hubbuhubbuh and it works great. The Micro puts out a decent amount of light for its size.

Robert Tilley

San Diego, CA

Sent from my iPhone

On Mar 16, 2023, at 7:55 PM, Matthew Williams <matthewwil...@gmail.com> wrote:

Hi everyone,