Having a problem with amp gauge showing discharge while driving after car is warmed up. Had problem with voltage regulator and generator and replaced regulator and had generator rebuilt. Works great showing correct gauge readings while driving until warmed up then gauge shows partial discharge even when engine rpms are brought up. Tried shutting off ignition and restarting but not change. Cleaned connections to generator and regulator and polarized before initial start up. When I shut off car after garaged checked battery and shows 12 volts between poles. Need some help here.