E-bike battery
safety

Hot, swollen, leaking or smells wrong?

No smoke, but something isn't right. These are the warning signs CPSC and NFPA tell riders to watch for:

• Too hotMuch hotter than usual while charging or riding
• Changed shapeSwelling, bulging, or a case that's cracked or split
• LeakingAny fluid, residue or stains around the battery
• Strange smell or soundChemical, burning or electrical smell; hissing or crackling
• DiscoloredDarkened, melted or warped casing or terminals
• Won't hold a chargeEspecially if it started suddenly, or after a drop or crash

What to do

• Stop charging. Switch off or unplug the charger at the wall, but only if you can do that without touching the battery.
• Stop riding it. Don't put it back on the bike or on the charger to "see if it's OK".
• If it's safe to do so, keep it away from anything that can burn, and away from doorways and the way out of your home.
• If it gets hotter, starts to smoke or makes noise, treat it as a fire: get out and call 911.
• Don't throw it in the trash or recycling bin, and don't ship it. A damaged lithium battery is dangerous to transport. Call us or your bike's maker for what to do next.

Charging safely

• Use the charger that came with your battery, or a replacement your bike's maker approves. A charger that plugs in is not the same as a charger that's safe for your battery.
• Plug straight into a wall outlet, not a power strip or extension cord.
• Stay nearby while it charges. Don't charge overnight while everyone's asleep, or while you're out. CPSC says many battery house fires have started at night during charging.
• Unplug when it's full.
• Charge on a hard surface, away from beds, sofas, curtains and anything else that burns, and not in the way of a door you'd need to get out.
• Mind the temperature. Let a hot battery cool down before charging, and follow the charging temperature range in your bike's manual.

Storing it, Florida edition

• Keep it out of hot cars, truck beds and direct sun. A closed car in a Florida summer gets far hotter than any battery should.
• Store it somewhere cool and dry, away from exits and things that burn.
• Keep it out of standing water and heavy rain. If it's been submerged, don't charge it; have it checked.
• Don't pile batteries together while storing or charging them.

Things we'll never tell you to do

You'll see some of these online. They're how batteries catch fire.

• Open up a battery pack, or try to repair or rebuild the cells yourself.
• Bypass or disable the battery's protection electronics (the BMS).
• Use a pack that's been modified or rebuilt with used cells by someone who isn't qualified. CPSC warns against this specifically.
• Use any charger just because the plug fits.

Buying a bike or a replacement battery

Look for a bike whose electrical system is certified to UL 2849, or a battery certified to UL 2271, by a nationally recognized testing lab. The label should be on the product, not just in the ad. CPSC urges buyers to choose products certified to these safety standards.

Each bike we list says which certification it carries. If it doesn't say, ask before you buy.

Recalls, and how to get rid of an old battery

• Check for recalls by searching your bike's brand at cpsc.gov/Recalls. Several e-bike makers have had battery recalls or CPSC warnings in recent years.
• Report a battery problem to the government at SaferProducts.gov.
• Recycle old batteries at a battery recycler or household hazardous-waste drop-off. Never put them in the trash or the curbside recycling bin. Call2Recycle lists drop-off sites by ZIP code.

Sources

U.S. Consumer Product Safety Commission — Micromobility Information Center and Important Safety Information Concerning Micromobility Devices
National Fire Protection Association — e-bike and e-scooter safety tip sheet
Your bike's owner's manual — for its charger, charging temperatures and battery care