Charging an e-bike safely and making the battery last

From the CPSC

• Use only the charger that came with the bike, or one the maker recommends. Never a "universal" or bargain replacement charger: CPSC warns these can fit but be incompatible, and can cause the battery to ignite.
• Replacement batteries: only ones the bike's maker confirms are suitable. Never a pack with modified, repurposed or used cells.
• Be home and awake while it charges. Don't charge it while you sleep or when you're out.
• Buy products certified to the applicable safety standards.

Source: CPSC Micromobility Information Center. Check it for the latest guidance and recalls. The same page covers riding safety too: lights, visibility and a helmet matter as much as battery care.

From fire-service guidance (NFPA)

• Store the bike and its battery away from exit doors and anything that can get hot or catch fire.
• Don't keep charging once it is full. Unplug when done.
• Stop using a battery that has an unusual odor, a change in color, too much heat, a change in shape, or that is leaking, smoking or not keeping a charge.

Source: the National Fire Protection Association's e-bike and e-scooter tips, as reported by Fire Engineering (October 25, 2022).

Our own additions (not from either source)

• Charge it where you can see it, in the spot you'd store it, not on a bed, sofa or by curtains.
• If it smokes or catches fire, leave and call 911; don't try to fight it.
• Look for certification of the bike's whole electrical system (UL 2849) on the product itself. A battery-only certification (UL 2271) is good to see, but it doesn't cover the whole system.

Habits that help a battery last

• Temperature. Most makers say not to charge below freezing or in high heat. In winter, bring the battery inside and let it reach room temperature before charging.
• Storage. For weeks or months off the bike, many makers recommend storing the battery partly charged (often somewhere between 30 and 60%) in a cool, dry place, and topping it up every month or two. Your manual's number wins.
• Avoid running it flat and leaving it empty. Deep discharges and long periods at empty are hard on lithium-ion cells.
• Keep the contacts clean and dry. Remove the battery before washing the bike if your manual says so, and never pressure-wash the motor or battery.

Range: what to expect

A brand's "up to" range usually assumes a light rider, low assist, mild weather and flat ground. Expect less with hills, a heavier load, higher assist, wind and cold. Our range estimates (in the chat) apply those factors and show a range, labeled as an estimate. If you need more range, look for a bigger battery or a manufacturer-approved second battery, or charge at your destination.

Recalls

Check your bike and battery against the CPSC's recall list at cpsc.gov/Recalls, and register your bike with the brand so it can contact you.

End of life

Never put a lithium-ion battery in household trash or recycling bins. Use a battery recycling drop-off; e-bike shops and local waste agencies can tell you where.