Flickering dynamo light

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JamesE
Posts: 411
Joined: 12 Feb 2013, 1:12am
Location: London

Flickering dynamo light

Postby JamesE » 5 Aug 2018, 5:08pm

The front light on my new Spa tourer has an annoying but not fatal problem: it dims regularly but very briefly, about every 18-20 seconds. It's a Busch & Muller Lumotec IQ-X with a sensor that automatically puts it into daytime mode; it looks like the flicker is the light briefly dropping into daytime mode and back again. Dynamo is an SP PV-8 and there's also a Toplight Line Plus rear light and a USB-Werk attached.

I asked Busch & Muller if the light is faulty and they suggested trying a different dynamo first. Anyone got any suggestions before I try rooting out a different front wheel and swapping everything around?

Toffee
Posts: 92
Joined: 2 Sep 2014, 9:28pm

Re: Flickering dynamo light

Postby Toffee » 5 Aug 2018, 5:19pm

Have you tried it without the usb werk attached?

andrew_s
Posts: 4660
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Flickering dynamo light

Postby andrew_s » 5 Aug 2018, 7:29pm

The USB-Werk would be my guess too.
It's got a cache battery in it, and it's possible that the dimming is it getting a regular charge state check.

JamesE
Posts: 411
Joined: 12 Feb 2013, 1:12am
Location: London

Re: Flickering dynamo light

Postby JamesE » 30 Aug 2018, 12:55pm

Belatedly: yes, unplugging the USB-Werk appears to have done it. Not a problem for me as I only use the USB-Werk in daylight but I've mentioned it to B&M as a possible fault. I wonder if I should let Spa know, too...