I apologyze, ... so far I've got somehow confused.
The right statement is:

1. With front light switched-off: dynamo output is 13-14V, 25Hz approx.
In turn e-werk max output is 13.3 Vdc.

2. With front light switched-on: dynamo output stabilizes at 7V, 25Hz approx.
In turn e-werk max output is 7 Vdc (actually a bit more at no-load conditions).

ConRAD