The clock confusion of (b) could be solved by changing the notation to "1h51m".
Also, maybe an up arrow for charging, a down arrow for discharging, and no brackets? This could be confusing though, since when the up arrow is displayed (charging), the time goes down.
The clock confusion of (b) could be solved by changing the notation to "1h51m".
Also, maybe an up arrow for charging, a down arrow for discharging, and no brackets? This could be confusing though, since when the up arrow is displayed (charging), the time goes down.