Looking around Amazon, it seems that different types of batteries are measured differently:

Does anyone know why?

  • Li-ion are measured in mWh

    • 1200mWh Cheap-Os
    • 3200mWh Deleepow
    • 3000mWh AmpTorrent
  • NiMH are measured in mAh

    • 2000mAh Eneloop
    • 2800mAh EBL
  • Alkalines are typically not measured

    • "Long Lasting" Duracell
    • "Longest Lasting" Energizer

I assume that Alkalines are not measured for some sort of historical reason with marketing departments?

... or is it that alkalines so mystical and unreliable that giving them a measurement is too aggressive? Or that switching to non-toxic / non-mercury was such a bad move in performance that measurements had to be removed in the 90s so people wouldn't know?

Perhaps NiMH are measured in mAh because the voltage can very so greatly and mWh doesn't make sense?

Are Li-ion measured in mWh because that's more consistent with non-battery measurements and they do deliver reliable voltage?