This is a history of all your charge sessions (each time you plug in the charger it's a new charge session). We show you the start time of the charge/discharge session, the duration, the starting and ending % levels, and the total mAh drain/gain. You can click on a card to open the historical charge (green numbers) or discharge (red numbers) screen for that particular charge session. If you know that you used a particular cable or charger during one session and another one for another session then you can use the history screens to compare their charging speeds (remember to use the box for charge speed with screen off). In the free version cards from the last 24 hours are clickable. The premium version unlocks all historical data.