Harry: Broom Polish, petrichor and wood. Ron: Toothpaste(what Hermione smells) Sugar quills and treacle pudding. Hermione: parchment, ink and books.
Immediately. If it dies once, it will die again. Get your battery replaced and your charging system checked. If the battery is in good condition, a simple running of the engine for about 15 minutes will be enough to charge it up.
It all depends on timing and this is why: If you like someone's Instagram post, they will receive a notification. However, the moment you unlike the post, the notification will be removed. If the person whose post you accidentally liked was online right at that moment, they would see the notification.