For the Primus Wind Power 1-AR40-10, what is the minimum wind speed required to charge the batteries? Posted by Ken Kotalik, Primus Wind Power on Jun 24th 2019 The "Startup Wind Speed" is 7 mph. At this cut in wind speed it will be a trickle charge. Primus Wind Power 1-AR40-10 startup wind speed minimum wind speed wind turbine wind generator wind power wind energy