Why the Cheapest Power Station Per Watt-Hour Isn't Always the Best Deal
Price per watt-hour measures only how much raw energy storage you get for your money — it says nothing about battery chemistry and cycle life (a LiFePO4 battery commonly lasting several times longer than an older lithium-ion cell before needing replacement), continuous and surge output rating, charging speed, or included accessories, any of which can make a nominally more expensive, higher-$/Wh model the genuinely better long-term value.
This is the most important caveat to keep in mind whenever using price per watt-hour as a comparison tool, which is exactly why this calculator's own disclaimer flags it directly.
Battery chemistry and cycle life
As covered in the LiFePO4-vs-lithium-ion comparison guide, two power stations with identical $/Wh can have dramatically different real lifespans depending on their battery chemistry — a unit that needs replacing after 500 cycles is a far worse long-term deal than one lasting 3,000+ cycles, even at an identical or higher $/Wh.
Output rating and charging speed
A cheaper unit per watt-hour might also have a lower continuous or surge output rating (limiting what it can actually run, as covered in the Surge Watts Calculator) or slower charging speed — both real, practical limitations that a pure storage-cost comparison doesn't reflect at all.