12 Volt Field Coils

[Dave Mann]

I changed to 12 volt in the 1980s primarily because the flashing rate of 6 volt flashing indicators varied considerably and as I used my Seven to commute into work I needed reliable indicators at night. A local alternator repairer put me onto the 12 volt idea when he sold me an electronic alternator voltage regulator for £4.50, so I removed the third brush, fitted a 32 ohm resistor to the CF3 cut out and I've run 12 volts for nearly 40 years. At that price I could afford to buy a second regulator as a spare which lives under my seat. On a long run to Beaulieu the ammeter seems to be glued on zero rising to 5 amps for a minute or so if I've been sat in stationary traffic. At night with 25 watt quartz halogen headlights (which draw the same current as the original 12 watt 6 volt bulbs) and LED rear lights the dynamo is producing about 7 amps well within it's capability.