http://www.fieldlines.com/story/2004/6/28/17546/9035 Zubbly and Ungrounded Lightning Rod were both helpful but I decided that it was easier trial and error than calculation...so here is what I tried...
45 turns of 26 guage wire 10 coils...after I finished hooked it up to 12 volts and it turned about 200rpm .... spun it 600 rpm with my cordless drill and got about 4.35 open voltage so at that rate I would have to spin it about 2400rpm to get a charging voltage for a 12 volt battery....1200 for a 6volt... Maybe I can change the position of the brushes? I do have a couple of small 6 volt batterys. If both of these plans don't work ...there is plan C....charging some NiCad batterys....Maybe I'll try rewinding an armature with even smaller guage and 200 turns....it is a learning experience...lot of fun besides!
( :>) Norm.
