Son 28 dynamo / Busch&Muller IQ Cyo N Plus 60lux front / B&M 4D lite plus rear

[Rohloff_Brompton_Rider]

Just a thought, are your headset bearings steel?

 

[Skipper9999]

Skipper is this the light you have link

Have you wired the rear light up to the output cable from the front light?
I would also recommend using twin core cable, relying on the frame for an earth is unlikely to be reliable.

I have a similar set up although my light is this one It is very bright and lights up fully with just the smallest spin of the front wheel

Yes that's the light I have and I have used the Schmidt CoAxial Wiring which is a tidy installation , I'm more than happy with the front output. The rears the odd one I can't understand why the unit drains itself dry ? So if I set off from home in the dark with light on and if I need to stop at the first junction the capacitor has no charge in it and hence no light . The front light I can turn off but not the rear . Unless I'm getting it wrong ?

 

[Skipper9999]

Don't worry skipp, it's not the first time he's had a go at me.

Just a thought, are your headset bearings steel?

It is a hope headset ! Is that steel ??

 

[Rohloff_Brompton_Rider]

Yep stainless iirc, so that can't be the reason. All I can suggest is either you've got the whole system polarity wrong, so the capacitor won't charge, or the rear light is fubarbed.

 

[ianrauk]

My dad is bigger the your dad posts have been deleted.
Keep on topic or there may be some thread bans.

Cheers.

 

[andrew_s]

With modern LED lights you should always plug the rear light into the front light if possible. If there's only one plug/socket, the other wire goes to the front light mount (making sure that it's the one marked as earth at the rear light end). Connecting direct to the dynamo in parallel, as was usually done when using filament bulbs, may well adversely affect the front light brightness.

The 4D Lite Plus has a couple of contacts on the side that you can short out with a key to drain the standlight capacitor.
They can also fail, in a carry on working sort of fashion. I had one I used to use with an E6 halogen front light that was fine for a couple of years, but later started taking quite a few yards (50 or so) to light up at all, and didn't reach full brightness for a quarter mile or so. I'm also of the opinion that it reduced the brightness of the front light significantly. I can't remember what the standlight was like for the early stops.
I ended up swapping for a Secu-Lite Plus, which has been fine, apart from knocking the lens/reflector off.