What Happened in Wakken
A woman riding an e-bike in Wakken, a village in West Flanders, Belgium, felt unusual heat on her legs during her ride. She stopped immediately, dismounted, and stepped away from the bicycle. Within seconds, the e-bike erupted in flames. The rider was unharmed because she reacted the moment she felt the heat, according to Belgian broadcaster VRT NWS.
The fire consumed the bicycle completely. Emergency services extinguished the blaze, but the frame and battery were destroyed. Investigators have not yet confirmed the exact cause, though initial reports point to a battery failure. No other property was damaged, and no one else was injured.
Lithium battery fires are rare, but they escalate rapidly once thermal runaway begins. Thermal runaway is a chain reaction inside the battery: one damaged cell overheats, ignites neighboring cells, and the fire spreads in seconds. The rider in Wakken had a brief window between feeling heat and seeing flames — a window that saved her from serious injury. Most e-bike battery fires occur during charging, not while riding, which makes this incident unusual and worth examining closely.
What Causes an E-Bike Battery to Catch Fire While Riding
An e-bike battery catches fire when thermal runaway occurs. Thermal runaway is a self-accelerating process: an internal short circuit or damaged cell generates heat, that heat damages adjacent cells, those cells short-circuit and release more heat, and the cycle repeats until the battery ignites. Once started, thermal runaway cannot be stopped by the battery management system.
Several conditions can trigger thermal runaway during a ride. Physical damage is the most common: a hard impact from a crash, a deep pothole, or repeated vibration over rough terrain can crack a cell's internal separator, allowing the anode and cathode to touch. Water ingress through a damaged seal can corrode connections and create short circuits. Manufacturing defects — contamination during cell assembly, misaligned separators, or poorly welded tabs — can lie dormant for months before failing under load.
Heavy discharge accelerates failure in a compromised battery. Climbing a steep hill, carrying a heavy load, or riding in high assist mode draws high current from the cells. If a cell is already weakened, that current generates more heat than the battery can dissipate. High ambient temperature compounds the problem: a battery sitting in direct sun before a ride starts hotter, leaving less thermal margin before runaway begins. Poor ventilation around the battery mount — common in fully enclosed downtube designs — traps heat and raises cell temperature during discharge.
European-certified batteries undergo testing to EN 15194 and carry CE marking, but no standard eliminates risk entirely. Testing includes short-circuit protection, overcharge cutoff, and impact resistance, but it cannot simulate every real-world failure mode. A battery can pass certification and still fail years later due to undetected damage or gradual degradation. Counterfeit batteries and uncertified replacement packs carry far higher risk because they often lack proper cell balancing, thermal fuses, or pressure vents. Buying from manufacturers who provide certification documentation and use cells from known suppliers — Samsung, LG, Panasonic, CATL — reduces but does not eliminate the chance of failure.
Early Warning Signs You Should Never Ignore
Heat is the first warning. If the frame near the battery mount, the downtube, or the area around your legs feels warmer than usual, stop riding. Batteries generate some warmth during discharge, but you should not feel heat through the frame or your clothing. Unusual warmth means a cell is overheating.
Smell comes next. An acrid, chemical, or burning plastic odor means the battery casing or internal components are overheating. Lithium-ion cells release gases when they overheat, and those gases smell sharp and unpleasant. If you smell anything unusual, stop immediately.
Swelling is visible evidence of internal failure. A bulge in the battery casing, even a small one, means gas is building up inside. Swelling indicates that cells have been damaged and are venting. A swollen battery can fail at any time and should never be charged or used again.
Performance drop without explanation suggests cell damage. If your range suddenly falls by 30 percent or more, or if the motor cuts out under load when the display shows adequate charge, the battery may have lost cells to internal damage. Degradation over years is normal, but a sudden drop is not.
Error messages or flashing lights on the display indicate that the battery management system has detected a fault. Common codes include over-temperature, cell imbalance, or communication failure. Do not ignore these warnings. They exist because the system has measured a condition outside safe limits.
Any of these signs warrants stopping immediately, dismounting, and moving away from the bike. Do not continue riding to reach your destination. Do not assume the problem will resolve itself. The gap between the first warning and a fire can be seconds.
What to Do If You Feel Heat or Smell Burning While Riding
Stop pedaling and turn off the system immediately. Press the power button on the display or battery to cut power to the motor and controller. This stops current flow and may slow the heating, though it will not stop thermal runaway if it has already begun.
Dismount and move at least 5 meters away from the bike. Do not stand next to it to assess the situation. Lithium fires can produce toxic smoke and intense heat, and the battery can eject flaming material if the casing ruptures. Distance is your primary protection.
Do not attempt to remove the battery if it is hot or smoking. Touching a hot battery risks severe burns. Pulling on a smoking battery can dislodge internal components and accelerate the fire. Leave the battery in place and let emergency services handle it.
Call emergency services immediately if you see flames or heavy smoke. In Europe, dial 112. Tell the operator you have a lithium battery fire. Firefighters need to know what they are dealing with because lithium fires require different tactics than ordinary fires.
Move the bike away from buildings, vehicles, or flammable materials if you can do so without approaching the battery. Use a stick or a piece of clothing to push the bike, not your hands. If the bike is already on fire or smoking heavily, do not touch it. Protecting nearby property is secondary to your safety.
Do not use water on a lithium fire unless instructed by emergency services. Water can react violently with lithium and spread burning electrolyte. Firefighters will use foam, dry powder, or specialized extinguishing agents designed for metal fires. If you have a fire blanket, you can drape it over a small fire to contain it, but only if the battery is not yet flaming and you can do so without getting close.
After the incident, do not attempt to charge or use the battery, even if the fire was small or self-extinguished. The battery is structurally compromised and can reignite hours later. Take it to a certified battery recycling facility or return it to the retailer. Many European cities have designated drop-off points for damaged lithium batteries. Do not put it in household waste or leave it in a garage.
How to Reduce the Risk of Battery Fire
Buy e-bikes and replacement batteries from manufacturers who provide CE certification and EN 15194 compliance documentation. These certifications mean the battery has passed tests for short-circuit protection, thermal management, and impact resistance. Ask for the documentation before you buy. If the seller cannot provide it, do not buy the product.
Avoid charging unattended or overnight. Charge your battery in a well-ventilated area, away from exits and sleeping areas. If a fire starts during charging, you need to be able to leave the building without passing the battery. Do not charge in a bedroom, hallway, or stairwell. A garage or utility room with a window is safer. Check the battery every 30 minutes during charging. Unplug the charger as soon as the charge is complete.
Inspect the battery casing and connectors regularly for cracks, corrosion, or swelling. Look at the seams where the casing halves join, the connector pins, and the mounting points. If you see any damage, stop using the battery and have it inspected by a qualified technician. Corrosion on the connector pins indicates water ingress and requires immediate attention.
Do not expose the battery to extreme heat. Direct sun in a parked car can raise internal temperature above 60°C, which accelerates degradation and increases fire risk. Storage above 40°C has the same effect. If you must leave your bike in the sun, remove the battery and take it with you. Store the battery indoors in a cool, dry place.
After a crash or hard impact, have the battery inspected even if the bike still works. Internal damage may not be visible from the outside. A technician can measure cell voltages and check for imbalance, which indicates damaged cells. If the battery took a direct hit, replace it. The cost of a new battery is far less than the cost of a fire.
Use the charger supplied by the manufacturer. Third-party chargers may lack proper voltage regulation, temperature monitoring, or charge termination logic. A charger that overcharges the battery by even 0.1 volts per cell increases fire risk significantly. If you lose the original charger, buy a replacement from the manufacturer, not a generic unit from an online marketplace.
Store the battery indoors at 20–60 percent charge if the bike will not be used for weeks. Full charge accelerates degradation during storage, and a degraded battery is more likely to fail. Check the charge level every few weeks and top up if it drops below 20 percent. For more detail on long-term storage, see our guide on how to store your e-bike battery during winter months.
What European Fire Services Say About E-Bike Battery Fires
Fire brigades across Europe have issued guidance on lithium battery fires as e-bike adoption has grown. The Dutch fire service, Brandweer Nederland, advises placing a burning battery in a container of water or sand if one is available and if it can be done without personal risk. Submerging the battery stops oxygen from reaching the fire and cools the cells. However, this guidance applies only to small fires where the battery is accessible and not yet producing heavy smoke or flames. If the fire is already large, do not approach it.
German fire services emphasize that lithium fires can reignite hours after being extinguished. A battery that appears to be out can restart thermal runaway as internal heat spreads to undamaged cells. German protocols recommend monitoring extinguished batteries for at least 24 hours or submerging them in water for the same period. This is why firefighters will often take a burned battery with them rather than leaving it at the scene.
Belgian authorities recommend keeping a fire blanket or ABC extinguisher at home if you charge e-bikes indoors. A fire blanket can smother a small battery fire before it spreads, and an ABC extinguisher rated for electrical fires can suppress flames long enough to evacuate. Neither will stop thermal runaway, but both can buy time. Place the extinguisher near the charging area, not in another room.
These are general guidelines, not instructions for untrained individuals. Always defer to emergency services on scene. Firefighters have thermal imaging cameras to detect hot spots, specialized extinguishing agents, and protective equipment. Your role is to evacuate, call 112, and provide information about what is burning. Do not attempt to fight a lithium fire yourself unless it is very small, you have proper equipment, and you have a clear escape route.
Are Some E-Bikes Safer Than Others
All lithium batteries carry some risk, but quality and certification reduce that risk significantly. Look for batteries with UL, CE, or TÜV certification and cells from known manufacturers. Samsung, LG, Panasonic, and CATL produce cells with consistent quality control and low defect rates. Batteries using cells from these suppliers are less likely to fail than those using unbranded cells from unknown sources.
Integrated batteries — built into the frame rather than removable — are not inherently safer than removable ones. What matters is cell quality, battery management system design, and thermal management. An integrated battery with poor ventilation and no thermal fuses is more dangerous than a removable battery with proper engineering. Frame integration can improve weather sealing and reduce the chance of impact damage, but it also makes inspection harder. You cannot easily check an integrated battery for swelling or corrosion without disassembling the frame.
Avoid unbranded or suspiciously cheap e-bikes sold online without documentation. If the listing does not specify the cell manufacturer, battery management system features, or certification standards, assume the battery is low quality. If the price is far below market average, the savings come from somewhere — usually from skipping safety features, using reject cells, or omitting certification testing. A cheap e-bike is not a bargain if it burns your house down.
Kimdyma bikes use certified battery packs with cells from established suppliers and comply with EN 15194. The battery management systems include over-temperature cutoff, cell balancing, and short-circuit protection. However, no battery is immune to damage from impact, water, or misuse. Even with a certified battery, riders must follow safe charging and storage practices. Certification sets a baseline; how you treat the battery determines long-term safety.
Frequently asked questions
Can an e-bike battery explode while you are riding it?
Yes, though it is rare. Thermal runaway can begin during discharge if the battery is damaged or defective. The Wakken incident shows that a rider may feel heat before flames appear, giving a brief window to dismount. If you feel unusual warmth or smell anything burning, stop immediately and move away from the bike.
Should I remove the battery if my e-bike starts smoking?
No. If the battery is already hot or smoking, touching it risks burns or accelerating the fire. Dismount, move at least 5 meters away, and call emergency services. Let firefighters handle removal. They have protective equipment and training for lithium fires.
Is it safe to charge my e-bike battery indoors?
Yes, if you follow precautions. Charge in a well-ventilated area, not overnight or unattended, away from exits and flammable materials. Use only the manufacturer's charger and inspect the battery regularly for damage. Do not charge in a bedroom or hallway. A garage or utility room with a window is safer.
How do I dispose of a damaged e-bike battery?
Do not put it in household waste. Take it to a certified battery recycling facility or return it to the retailer. Many European cities have designated drop-off points for lithium batteries. If the battery is swollen, smoking, or has been in a fire, contact your local waste authority for guidance on safe transport.
Related reading
Why You Should Never Leave Your E-Bike Battery in the Sun
Dutch fire services warn that e-bike batteries left in direct sunlight—during a lunch stop, in a car, or in a greenhouse—can overheat and ignite. This guide explains the temperature thresholds, safe parking habits, and what to do on hot days.
