Hi, I measured it with a voltmeter.
When the car's off it's 12.4 volt, all good.
When I start the engine (cold), and it runs idle, it goes up to 16.7 volts )-;;

I think it's the voltageregulator (don't know if this is the right word) on the alternator. Do you have experience on replacing it? (is it welded, clicked or something else?)