I bought my kids a hover board for Christmas a few years back. Then it was in the news that some, a different brand, were catching fire on people. I never liked the thought of lithium ion batteries charging unattended after that. I started placing it to charge away from the walls on on ceramic tiles in case it start to burn. Even cell phones I feel better with them charging in a glass dish. Call me paranoid but I’ve seen too many internet videos of these types of batteries spontaneously bursting into flames.