Home charging cost, off-peak (22:00–06:00, 3.5p/kWh)
A "charge" sums all home kWh from sessions starting in that overnight window.
Overnight battery change (00:00–07:00)
Positive = charge lost overnight. Negative = it charged during that window. Nights the car stayed asleep the whole time have no reading to compare, so they're omitted.