HP Calculators
Got my HP 45 out to use for a class I'm teaching and couldn't find the battery pack or charger. I bought a replacement battery pack on E-bay and charged it externally. This was very inconvenient so I made a charger with a custom made plug (For sale - see the HP Charger / Battery page). This experience reinforced my love for these machines. An excellent site for info about HP calculators is the Museum of HP Calculators. This is a great site, a wealth of information. They sell a 2 DVD set with tons of information about HP calculators, calculator programming, HP publications etc. I bought the DVD, and recommend it wholeheartedly.
See additional information about HP batteries and chargers, restoring an HP-67, and the timer modification for the HP-45.
Battery and Charger Information