E-bike, scooter and hoverboard batteries: look for UL 2849 or UL 2272, use the charger it came with, and never charge overnight

Why these batteries need care

A ride’s battery packs a lot of energy into a small space. If a cell is damaged, overcharged, charged with the wrong equipment, gets too hot or too cold, or has a defect, it can overheat and catch fire. [S5]

• Thermal runaway. CPSC describes it as a self-sustaining reaction inside a cell. The heat ignites the cell’s flammable electrolyte, and the fire can set off the cells next to it and ignite things near the battery. [S3]
• Charging is the riskiest time. In CPSC’s 2019 to 2023 count, 120 of 227 incidents (53 percent) happened while the product was plugged in. Another 23 happened while it was just parked or stored. [S3]
• Night is the worst time. CPSC says it has seen many lithium-ion battery home fires and deaths at night, while batteries were charging and families were asleep. In CPSC’s review, most deaths and serious injuries came from the home and furnishings, such as furniture and bedding, catching fire once the battery did. [S1] [S3]

Before you buy one, or give one

If one is on a holiday list, give the label a minute before checkout. [S1] [S8]

• Certified, not just compatible. CPSC tells shoppers to choose devices and batteries certified to the voluntary safety standards. FDNY names them: UL 2849 for e-bikes, UL 2272 for scooters, hoverboards and other personal e-mobility devices, and UL 2271 for battery packs sold on their own. [S1] [S3] [S8]
• The whole ride, not one part. UL 2849 covers an e-bike’s whole electrical system, from the battery pack and motor to the charger. UL Solutions warns that a ride with a certified battery, motor or charger isn’t the same as a certified ride. [S3] [S6]
• Look for the lab’s mark. FDNY says to look for the logo, mark or name of the accredited testing laboratory that issued the certification. [S9]
• Buy from a seller you trust. FDNY puts this first on its list, next to the certification check. [S8]
• Add the helmet and check the limits. CPSC says to always wear a bicycle helmet, and to check the device’s weight and age limits before anyone rides. [S1]

For now these UL standards are voluntary. In June 2026 CPSC proposed making them mandatory, with added requirements such as tamper-resistant battery cases and a test for chargers wired with the wrong polarity. Written comments closed August 24, and a hearing for oral comments was scheduled for October 21, 2026. It’s still a proposal, so the mark on the box is what you can check today. [S3] [S4]

Reading the label

Pick what the box or the listing says to see what the sources make of it.

Have a mark with a file number? UL Solutions says you can look up its own certifications in its free Product iQ database. [S6]

The charger: the one it came with

CPSC is blunt about this one. Use the charger that came with the device, or one the maker recommends. [S1] [S2]

• “Universal” chargers. They can fit the port and still be wrong for the battery, and an incompatible charger can make the battery ignite. CPSC got 156 reports of fires and thermal incidents involving universal chargers between January 1, 2023 and May 16, 2024. [S2]
• Lost it? Ask the device’s maker which replacement charger is compatible. Don’t borrow the charger from another e-bike or scooter unless you’ve confirmed it works with yours. [S2]
• Why it matters. CPSC’s proposal explains that the charger’s output voltage, current and plug polarity all have to match the battery, or the battery can be damaged and catch fire. [S3]
• Replacement batteries. Use only one the device maker confirms is suitable. Never use a pack that was rebuilt by someone unqualified or that holds used or repurposed cells, and don’t build, open or repair one yourself. [S1] [S8] [S10]

Where and when to charge

The fire departments and safety groups agree on most of this. [S1] [S5] [S8] [S9]

• Home and awake. Stay home while it charges. Don’t charge it while you sleep or when nobody’s home. [S1] [S2] [S7]
• Unplug when it’s full. NFPA says to stop charging once the battery is full, and CPSC says not to leave the charger connected for long periods. In a ULSE survey, 55 percent of e-bike owners admitted leaving theirs plugged in after a full charge. [S2] [S5] [S7]
• Straight into the wall. FDNY says no extension cords or power strips. Our power strip guide explains what those labels mean. [S8] [S9]
• Keep your way out clear. Don’t charge or park it where it could block the only exit from a room. FDNY adds apartment doors, bedroom doors and windows, especially a window with a fire escape. [S5] [S9]
• On the floor, away from things that burn. Not on or near a bed or couch, drapes or papers, and not in a bedroom. [S8] [S9]
• Out of the sun and away from heaters. Direct sunlight and nearby heat sources are on the NFPA, ULSE and FDNY lists. [S5] [S7] [S9]
• A working smoke alarm nearby. One maker’s manual says not to store its battery anywhere without smoke alarms. Our smoke alarm guide covers the chirp and the date check. [S10]

Cold garages and winter storage

NFPA and FDNY say not to store these batteries in extreme heat or cold, and FDNY and ULSE say not to charge them that way either. ULSE adds that thermal runaway can start hours or even days after a battery is damaged or exposed to extreme temperatures. [S5] [S7] [S9]

• Follow your manual’s numbers. As one example, Bosch’s manual for its PowerMore 250 e-bike battery says the battery will only charge between 32 °F and 104 °F, and should be stored at room temperature. Your battery’s limits may differ. [S10]
• Parking it for the winter. The same manual says that if the battery won’t be used for more than three months, store it at about 30 to 60 percent charge and check it after six months. It also says not to leave it permanently connected to the charger. [S10]
• Not used often? CPSC says to follow the maker’s guidance on how often to charge a battery you aren’t riding. [S2]

Signs of trouble, and what to do

Look the battery over now and then, and every time after a crash or a fall. [S7]

• Warning signs. Heat, an unusual smell, swelling or a change in shape or color, leaking, smoke, or hissing or popping sounds. Dents and punctures count too. [S5] [S7] [S9]
• If you notice one. Stop using or charging it. If it’s safe to do so, move it away from anything that can catch fire, then call 911, FDNY says. [S8] [S9]
• If it’s smoking or burning. Get everyone out. FDNY says closing the door behind you as you leave helps hold back smoke and fire. Then call 911. [S8]
• Damaged gear. Don’t charge a battery or charger that’s damaged, and have repairs done by a qualified professional. [S5]

Old batteries and recalls

• Not in the trash. Lithium-ion batteries don’t go in household garbage or recycling bins. Take them to a battery recycler or a household hazardous waste collection site. [S1] [S5]
• Don’t keep a dead one around. FDNY says to take a replaced battery out of your home right away, even if it isn’t damaged. [S8]
• Recalls. CPSC’s micromobility page lists e-bike, e-scooter and hoverboard recalls. If your battery is recalled, follow the disposal steps in CPSC’s notice. [S1]
• Report a problem. CPSC asks people to report battery problems at SaferProducts.gov. [S1]

Your situation

Pick the one that fits to highlight what the sources say.

Before the next charge

Quick answers