But then there will be a drop of about 1.4 volts (2* 0.7V) (assuming silicon diodes) across the bridge rectifier so a 3V battery will be as good as a 1.6 V battery only. You need something better than this (may be based on this http://en.wikipedia.org/wiki/Low-dropout_regulator[^]) The best way to accelerate a Macintosh is at 9.8m/sec-sec - Marcus Dolengo