The WHITE wire connects to the regulators regulated AC output (e.g., yellow on Vespa type regulators). The RED wire goes to the + side of the battery (which charges the battery with rectified DC current). The circuit runs: Flywheel AC(~) out » Regulator AC (~) in » Regulator AC(~) out » White wire of Rectifier » Red wire of Rectifier » positive terminal on Battery. You may have to drill a hole to mount it.