12V Dynamo Conversions
There are two ways to achieve a conversion from the standard 6v system as used on all LUCAS E3L powered British bikes.
It is a property of any dynamo that the faster it spins the more voltage it will produce, it is the purpose of the regulator box to ‘set’ the level at which the system operates.
- The easy way to perform a 12v conversion is basically to use your existing 6v dynamo and couple it to a 6-12v convertor electronic regulator.
In a normal 6v system the dynamo will start charging at around 1000 rpm, to power a 12v system the dynamo now starts charging at about 1500rpm. This is not usually a problem as you would not normally ride around at such a low RPM.
To lower the RPM at which charging occurs you can fit an srm Dynamo belt conversion kit (which has a slightly higher overall ratio than the standard chain drive and will speed the dynamo up).
- The other method to achieve the 12v system is to replace the dynamo armature and field coil ‘wound’ for 12v. To do this the thick 6v windings have been replaced with twice as many windings of thinner wire. The number of windings is proportional to the voltage produced - so the dynamo now produces 12v at 1000rpm. Since the wire in the 12v windings is thinner it can only carry half the current (amps) of the 6v windings so there is no actual gain in output power. As a consequence the 12v wound dynamo must be used with a compatable electronic regulator to prevent them from burning out.
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