Caution: Why Hoverboards Are Exploading

Two wheel electric self-balancing scooter. Red

You’ve probably seen some celebrities or even your neighbors down the street using one of the most anticpated toys of the Christmas season: the two-wheeler “hoverboard” as many call them. But before you play Santa and go out to get one of these for your loved ones, beware. They are causing a lot of injuries, accidents and even blowing up into flames while people are riding them.

Patty Davis, a spokeswoman for the U.S. Consumer Product Safety Commission (CPSC), says injuries have become increasingly common in recent months. Since August 2015, the agency has received 29 reports of emergency-room injuries related to the hoverboards, and is investigating at least 10 fires in 9 states.

The injuries treated in emergency rooms include fractures, strains, sprains, contusions, lacerations, and head injury, she says.

Multiple accounts of the devices catching fire and blowing up have been reported around the country, too. The country’s three largest airlines — Delta, United and American — said they would no longer allow them on planes because they pose a fire hazard. New York City has banned them, with police citing an existing code against motorized scooters.

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An exploding two-wheeler burned down a house in Louisiana in November; another scooter combusted in the same state in the past week. Another board caused significant damage to a home in New York a few days ago. And even at a mall in Washington this week, a hoverboard caught fire and shoppers were forced to evacuate.

But what is actually causing all these fires? In the New York and Louisiana incidents, the board was plugged in and recharging. In the mall incident, the board wasn’t plugged in at all; there have also been reports of scooters bursting into flames while people were riding them. Plugged in or not, the big problem has to do with the quality of the rechargeable lithium-ion batteries inside these things. They’re almost always tucked in one of the foot rests, and they work the same way as the lithium-ion batteries in our smartphones, tablets, and laptops. But, they’re just a lot more prone to defects.

Jay Whitacre, Professor of Materials Science & Engineering at Carnegie Mellon University, tells WIRED.com that the problem doesn’t have to do with these self-balancing scooters themselves, but with the quality of the batteries being used. They’re cheap, and cool to look at when someone is riding them. Predictably, a whole bunch of cut-rate brands are flooding the market, but they’re made from cheap components.

“There are a lot of factories in China that now make Li-ion batteries, and the reality is that the quality and consistency of these batteries is typically not as good as what is found in top tier producers such as…