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Hoverboards, or self-balancing scooters as they're also known, have been hot this holiday season – in more ways than one, unfortunately. There are now reports of at least 11 of these two-wheeled personal transporters overheating and catching fire, according to the Consumer Product Safety Commission (CPSC).

Fires have taken place both during charging and recharging, and even while the scooters were being operated. With CPSC investigating scooters and some major retailers, including Amazon and Overstock.com, dropping sales of many or most models, we think it's wise to postpone buying a board until there’s a clearer sense of which brands are problematic and more information is released.

That recommendation is not based on any specific problems with the six scooters, ranging in price from $300 to $1,000, we bought earlier this month and have been testing. In nearly a week of operation, including hours of riding and repeatedly charging and recharging their batteries, none of the models have become notably hot, either during operation or while recharging.

However, speculation so far is focusing less on the design of these devices than the vulnerability and quality of their lithium-ion batteries. These hefty cells – most weighing around 2 pounds and measuring 13.5 x 9.5 inches – pack the power to run between four to five hours in our tests, depending on the model and the weight and the rider.

Yet, as Wired magazine notes, especially when such batteries are mass-made at low costs, manufacturing flaws can result that allow the battery's cells to short circuit and possibly cause fires. Even well-made batteries, the magazine notes, could be damaged in the rough and tumble of regular use, which, with our staffers, involved plenty of collisions between the scooter and other objects.

A CPSC spokesperson said the agency is conducting its own tests on samples of brands that have been problematic, but it is not yet releasing the names of those models until the cause of the fires can be determined. In the meantime, the agency isn’t specifically recommending against buying boards. Yet it is advising consumers to buy only from "reputable retailers" and seek out models that have "recognized certifications for safety."

It isn’t clear how many models, if any, currently bear such certifications. None of the models we tested list the badges familiar to North American consumers, such as Underwriters Laboratories. Around half of the models we're testing bear a "CE" certification, for "Conformité Européenne." However, ANEC, a European agency that represents the standardization and safety interests of consumers, warns that the CE badge "is not a mark of safety, nor a mark of quality, and has never been intended as a mark for consumers."

Some scooters remain available on sites, including Amazon, but it isn't yet clear how much those models vary from others that have been removed from sale by some retailers; in our tests, multiple models we bought appeared to be all but identical when we opened up their backs and examined their internal components.

So what should you do if you’ve already bought a scooter? If it's unopened, you may want to consider returning it, or at least leave it unopened until investigations, such as that by CPSC, yield more data. For those who are already using a scooter, the agency advises that you not charge the scooter overnight, and to not charge it before wrapping it as a gift to minimize any chance of fire. See our video on safe scootering for more tips on how to avoid injuries when riding.

We’ll continue to monitor reports and investigations on these products, and consider publishing reviews of some or all of the models we've ordered when their safety becomes clearer.

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