The charging status only shows regenerative braking, not charging from the engine running. However, unless the battery is full, it is always charging while the engine is running. Leave it in sport mode and you will see the battery charge indicator go up until full. But unless you have another reason to run in sport mode, this has a negative effect on efficiency. Simply speaking, running in sport mode will reduce your mpg significantly, even after using the extra charge accumulated in the traction battery.