I use three AA alkaline batteries in a RadioShlock holder; the batteries stay external to the case, while the leaders are soldered to the battery goal post I left after removing my Nite Owl. The batteries hold for about 12 months....time to check mine! The setup was suggested by the hardware guy in the old AOL Apple II section (or was it GEnie??) Good Luck.....I'm typing on my ROM 01 now!