I have a box full of batteries (AA, AAA, 9V, and CR2032). I know some are empty because I chucked them in there together with full ones, which was probably not a smart thing to do.
Is there an easy way to know the (approximate) charge of these batteries? For the AA & AAA I don't have any device that accepts just a single battery, and for the 9V & CR2032 I have just one device where changing the battery is comparatively a lot of work (smoke alarm & light switch).
I have a multimeter, but I remember from a few years ago that measuring the volts doesn't seem to give a good indication of charge...