Going thru my pile of old batteries, I discovered 3 1995 Polaroid pola-
pack batteries. They still read above 7.2 V. I think they were 7.5V
when new. Whatever chemistry they used has held up for 16 years. I
am wondering what the chemistry of these batteries is that they
haven't self-discharged after this long period of time. Does anyone
know for sure what Polaroid used?