Powerdynamo brings new ignition & light 
to your vintage motorcycle



Technical Help



You report: "I get abnormal voltage values from regulator" 
  • Very often you find (especially with a digital instrument) abnormal voltage readings at the regulator output.
    =>> this is in most cases NO indication of failure !

    most instruments expect smooth DC or 50 Herz AC with sinus shape.
    A motorcycle magneto dos not give such voltage. There always is some underlying and changing (with engine speed) frequency which fools your instrument.

    short video on this here  (there with increasing speed you see voltage READING drop, than condenser is added - voltage READING rises, again disconnected, reading drops again)

  • If you read substantially more than 15 Volts with a connected (working!) battery you for sure have a case of wrong reading.
    The system can never bring a 12V battery to near 20 or so volts. Impossible!

    Also if you read only 10 or so volts and degreasing with increased engine speed you have a misreading problem - or a battery which is absolutely dead and consumes all energy converting it into heat.
  • Better than grabbing some voltage meter is to observe headlight behaviour. If the light shines brightly  (with engine speed a little over idling) and bulbs do not blow indications are that all is OK.

    To check battery loading, better use an Ammeter in line to battery and check whether and how battery is charged (or discharged)

    please see also the KB entry under 

    - regulator defective?
    - what battery shall i use 
    - 65W headlight is often too much
back to trouble shooting


to Knowledgebase