Calculator collection : How to power calcs without constantly opening?

[Eric Rechlin]

The best thing is to buy lithium AA and AAA batteries for powering infrequently-used devices. They don't leak like alkalines and have a very long shelf life (rated for 20 years). I use the Energizer Ultimate Lithium brand. They are about US$1.25 each where I buy them at Home Depot, so about 5x the price of alkalines, but that's a small price to pay for the protection from leakage in something you use infrequently.