[bamboozled]

What should it be measured in?

[jdsully]

watt/hours is the typical measurement. Raw wattage is insufficient without a time component.

[rightbyte]

Wh, not W/h. W/h is a change in power.

"Scotty, increase engine power by 1 gigawatt per hour!"

[epistasis]

And for a lot the initial lithium ion storage on the grid, which was used for frequency regulation, the W/h or ability to respond to powe change, was a far far more important characteristic of the batteries than the Wh.