REBOOT · 2312 V12 V
What this step adds; in part B, live currentParts already in placeAn overshot wheel 2.4 m across under a 2.6 m head. Water power is 9.81 × flow × head; the wheel keeps about 80% of it, and the gears, belt and a car alternator about half of that again. A 120-tooth ring on the wheel turns a 10-tooth pinion, and its 1 m pulley belts a 12 cm alternator pulley, 100:1 in all. A car alternator does not charge below about 1,000 rpm, so below 32 L/s the wheel turns and nothing reaches the batteries. Fully open, 60 L/s gives about 612 W, ten 60 W bulbs' worth; the string has six. This is a guide to how the parts go together, not engineering drawings: have the dam, the wheel's bearings and the wiring checked before you build, and fuse the battery leads.