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Dynamo question.

iainmossiainmoss Posts: 88
edited October 2008 in The workshop
I've splashed out on a Busch und Muller Dynamo (Dymotec 6) & rear light (D-Toplight plus).

Do I have to use both a front & rear light with a dynamo?

I was intending to use the dynamo just for a rear light but I keep reading things about overload if only one light is working.

Please confirm or deny my suspicions!



  • PositronPositron Posts: 191
    I've got similar but just power the front light - as rear LEDs are so good. To do this you replace the 2.4W front with a 3W as it takes everything. You can just about get away with running the 2.4W lamp alone on 3W and it won't blow if you're lucky. But run a standard 0.6W rear and it'll almost certainly blow. So you could put a 3W lamp in the back but it will be very bright. Is this what you want? What are you planning on having up front - some fancy rechargeable battery thing? Personally for "lit" commuting in the dark I think now I'd go with dynamo lights front AND back - with LED backups front and back - yes even using dynamo lights with standby - and I'd probably get a hub dynamo now.

    Sorry - short answer - you need to match your dynamo power output to the total on you front and/or rear lamps.

    Good luck - only a week of "daylight" left...

    Never order anti-pasta to arrive at the same time as pasta.
  • Thanks for the info, Positron.
    I have now decided to get a front dynamo-powered light too to make a useable set.

    I was planning on using a battery powered lamp up front but realise a dynamo lamp, especially a good one, will be sufficient.

    On my daily 15 mile commute I ride country roads (major & minor), unlit cycle paths and suburban & urban roads: every sort of paved environment imaginable! I'd say its about 60:40 lit to unlit.

    I have decent LED lights to use as a back-up already but the front does not give enough light for the unlit sections over 10mph. (So frustrating!)

    Off the LBS this weekend to get a front lamp!

  • sdg_77sdg_77 Posts: 11
    I've been using a Shimano Hub dynamo for three or four years now and had no problems with it - a front light with some sort of backup for when you stop is useful - mine is a Lumotech Standlicht - after about 20metres it's charged up enough to stay on while I wait to turn out of the car-park at work. At one time I used to cycle along an unlit road - the Lumotec gave enough light to avoid the potholes and general road junk.

    I have a Toplight D on the back and both it and the front light have been very reliable - the Toplight is bright and very visible from the sides.
    To avoid blowing bulbs you can fit a zener diode - but you'll probably find a B&M front light has one built-in.
    At this time of year - not being able to forget your lights is something of an advantage.
    FCN 8 (ish)
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