Can't find any component spec delineation on Nihola's Family web page, but those front hubs look like Sturmey-Archer X-SD single sided 70mm drum brake hubs. If so, swap the right-side one out for an X-SDD dyno hub.
Sturmey-Archer | X-SDD
6 volts, 3 watts, no waiting, power LED lights, no batteries, Bob's your uncle, hoodibaba: