Is 21 grams as heavy as a Battery (AA)?
It's about nine-tenths as heavy as a Battery (AA)
The weight of a Battery (AA) is about 24 grams.
(Alkaline)
An "AA" size battery weighs 24 g. AA batteries came into common use during World War II and were given their name by the American National Standards Institute (ANSI) Committee C18 because they were smaller than the "A" size batteries which were invented first.
There's more! See other comparisons to 21 grams...