Joined: Jan 2009
Posts: 44,199
Likes: 6,440
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
I installed one of those Sanyo under-BB dynamos on my wife's bike. It grounds to the frame. I connected a ground wire between the lights and a water bottle bolt, and it works fine. (And of course, there is a hot wire between the dynamo and the lights.)