SK400ii V power question

I have just ordered a kit with 3 SK400ii V lights. Does anyone know how long the included power cords are? (I speak both real units and persistent ancient units) How much current does the light draw while charging? IE how many I can safely add to a 15A/220v power circuit? I’m expecting to use a 2.5mm 3 core extension cable system to connect the lights I intend to use the lights both at home and on client premises- kind of a mobile studio. I normally do portrait style shoots, family/maternity/new born/etc… and so I’d prefer to make a custom single extension that can feed all three lights and only needs a single socket (I’m certified to create electrical extension cords in my country).

Any assistance would be appreciated.