HP Prime Battery consumption analysis

[debrouxl]

Well, AA is a comparatively large form factor, which would make the calculator much thicker, and therefore much less suitable to nowadays' marketplace
Even AAA, by far the most popular battery type for calculators (*), is being phased out from newer models (TI-Nspire CX, HP Prime, TI-84+CSE / 83PCE / 84+CE), replaced by Li-ion batteries with thinner form factor.

*: well, at least in TI calculators, which I'm more familiar with, but my 50g uses AAA as well, so its closest ancestors probably do. The HP-41 uses the even smaller R1 batteries, IIRC.