Level is sampled every 30 s. The rate is a line fitted through the points where the level actually changed, over the last 20 minutes — widening to 90 if the drain is slow. That settles the reading instead of letting it jump with each 1% step.
Watts = rate (%/h) × the capacity above. That is design capacity — an aged battery holds less, so real figures run lower.
Charging figures are energy going into the cell, not draw at the wall (a charger is roughly 85–90% efficient).
Gaps over 15 minutes (sleep, closed lid) start a fresh measurement rather than averaging across them.
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