by Erika Soliven, Marketing Director at PowerShelter
·
Updated
Summary
What building managers need to know about e-bike battery fire risks:
Most e-bike battery fires start with an uncertified battery, an incompatible charger, or physical damage to the cell. The Fire Department of the City of New York, Toronto Fire Services and London Fire Brigade report the same causes.
Toronto Fire Services describes a battery in thermal runaway as almost impossible to extinguish; firefighters can only contain the spread and wait for it to burn out.
London Fire Brigade responded to a record 171 e-bike fires in 2025, up from 48 in 2021.
In the Netherlands, building fires caused by batteries doubled between 2019 and 2024, according to Stichting Salvage figures cited by Brandweer Nederland.
Insurers are attaching conditions to where e-bike batteries can charge. Hotel Okura's insurer gave an ultimatum: batteries out of the building, or the policy was at risk.
Riders charge where it's convenient: stairwells, corridors and storage rooms. A purpose-built battery charging locker keeps the fire risk out of those spaces.
What causes e-bike battery fires
Battery cells fail for a small number of reasons. A dropped or crushed battery can be damaged inside without any visible sign, and fail later. A non-original charger pushes current that the battery was never built to accept. Every battery has a management system (the electronics that regulate charging and keep cells balanced), and a mismatched charger can overwhelm it. Cheap replacement batteries and aftermarket conversion kits often carry no such system at all, which is why London Fire Brigade, FDNY and Toronto Fire Services highlight uncertified and second-hand purchases as the common thread.
Age and heat compound all of it: a cell several hundred cycles old tolerates far less than a new one. Charging is one of the points at which these failures surface. A full charge takes several hours, and the battery is often left unattended, usually indoors. That's a window in which a fault becomes a fire.
Why a lithium-ion fire behaves differently
The mechanism is thermal runaway: a failing cell heats, vents flammable gas, and drives its neighbors into the same reaction. Because the cell releases some of its own oxygen as it breaks down, the reaction can keep going even when cut off from air. Water cools it but does not smother it, and a standard extinguisher does neither well.
"When these batteries go into thermal runaway, they are almost impossible to put out."
Marla Friebe, Deputy Fire Chief of Community Risk Reduction, Toronto Fire Services
Firefighters contain the spread by cooling the fire, waiting for the battery to burn itself out.
But before any of that happens, the battery cell off-gasses: it vents hydrogen, carbon monoxide and carbon dioxide. This gap between venting and flame is short, and it is the best chance to intervene. A smoke detector responds once there is fire; a gas sensor can pick up the off-gassing first.
Where the risk sits in a building
Riders detach the battery and carry it to wherever charging is possible, which is rarely where it is safe. In an apartment building, that means wherever an outlet is accessible, from the balcony to the broom closet. In an office, it means on the desk, by the supply closet, in a shared kitchen or wherever an extension cord can run.
The theft risk compounds it. A battery is the most valuable removable part of an e-bike, so riders bring it indoors rather than leave it unattended. Wherever the battery ends up, it is inside the building with everyone else.
"Firefighters are currently attending an e-bike or e-scooter fire every other day, on average. These fires can be explosive and have devastating consequences."
Europeans bought 5.1 million e-bikes in 2023 alone. With most being urban commuting bikes, a building is no longer managing one person's battery but dozens, whether they charge overnight at home or from 9 to 5 at the office. The Netherlands shows where that leads: building fires caused by batteries doubled between 2019 and 2024, according to Stichting Salvage figures cited by Brandweer Nederland.
Who is responsible
The answer depends on the type of building, and both versions land in the same place.
In a workplace or a commercial building, the operator controls the premises and, in most jurisdictions, carries the duty of care. If a rider charges from an outlet you provided, in a space you manage, that charging falls within your duty of care, not just the rider's.
In residential buildings the picture is messier. Someone charging inside their own home is largely their own business, but common areas, storage rooms and shared corridors belong to whoever owns or manages the building. Blanket bans are common and rarely work, because a resident who cannot charge in the common areas charges in the hallway or the apartment instead.
Insurers tend to move first, because they don't need permission to change a policy. Where a policy attaches conditions to how and where batteries charge, a safety question becomes a financial one. Hotel Okura Amsterdam, a luxury hotel, reached that point when guests began bringing batteries into the building and charging them under their chairs during dinner in the hotel's Michelin-starred restaurants. The hotel's insurer issued an ultimatum: batteries out of the building, or coverage was at risk.
Rather than ban e-bikes, management installed two charging lockers on the exterior premises, one for guests and another for staff, next to their bike parking.
What reduces the risk
Five measures do most of the work. They run in sequence, from the first sign of a failing cell to the alarm that reaches someone.
Sense the failure. Sensing has to happen at the gas stage rather than the smoke stage, which means detectors for hydrogen and CO alongside temperature.
Cut the power. Power has to cut automatically at threshold, per compartment, because a control that waits for a person is not a control at night.
Clear the gas. Extraction has to remove gas that could otherwise ignite.
Separate the batteries. Each battery needs its own non-combustible compartment, rather than sharing a desk, a shelf or an open room with other batteries and whatever else is nearby.
Tell somebody. The alarm has to reach people, on site and off.
Separation matters even when nothing is charging. FDNY found that 59 percent of New York's lithium-ion battery fires in 2023 started when the battery was not charging, which makes secure storage as much of the answer as controlled charging.
Not every site needs all five measures. A locker that sits outside the building can rely more on passive protection, because open air and distance from the building do much of the work. A locker inside an occupied building needs the full sequence, since ventilation, distance and open air can no longer be assumed. The trade-offs between indoor and outdoor charging depend on the site. PowerShelter's lockers cover these measures to different degrees. The SmartShelter carries the full set, indoors or out. The CoreShelter is built for outdoor sites: each battery charges in its own stainless-steel compartment, and each unit has its own circuit breaker.
Either way, that is the difference between a battery charging locker built as infrastructure and a closet with outlets in it. Both hold batteries. Only one assumes a battery will fail. PowerShelter lockers have been tested under thermal runaway conditions following VDMA 24994 methodology. The full specification sits on our e-bike battery charging safety page, and the thermal runaway test certificate is available to download.
Open outlets and generic storage | A purpose-built battery charging locker (SmartShelter) | |
|---|---|---|
Where charging happens | Wherever an outlet is free, riskier if by an escape route | In the locker's own compartments, outside or inside the building |
How a fault is found | Visually, after smoke or flame | Gas and temperature sensors, often before smoke or flame |
Power control | Continuous until someone unplugs it | Automatic shut-off at threshold, per compartment |
Gas build-up | Accumulates in the room | Extraction removes it during charging |
Separation | Batteries share desks, shelves and rooms | Each battery in its own stainless-steel compartment |
Oversight | Someone notices, or nobody does | Built-in alarm, with remote alerts where monitoring is set up |
Evidence for your insurer | None | Documented placement and controls |
Hotel Okura Amsterdam, ROC Hilversum, Thales and a national heritage institution in Amsterdam all reached the same conclusion: give riders somewhere better to charge than the building itself.
FAQs
How do you extinguish a lithium-ion battery fire, and can building fire systems handle one?
You mostly cannot extinguish one. Firefighters apply large volumes of water to cool the surrounding cells and contain the spread, then wait for the battery to burn itself out, and reignition hours later is common. Standard extinguishers and most conventional building suppression underperform, because they are designed for fires that can be smothered. That is why containment has to be built into the enclosure rather than left to the building: each compartment in a purpose-built charging locker carries passive propagation resistance, so a single cell failure is slowed before it can reach the batteries beside it, and higher-specification units add active suppression at the source. Detection matters just as much, because gas sensors can cut power to a venting cell before there is anything to extinguish.
What happens when a charging locker detects a fault?
On a SmartShelter, charging power cuts automatically, a local alarm sounds and the warning appears on the unit’s touchscreen. The same alert goes to an online dashboard, and the property owner decides who has access to it: a facilities team, a security desk or a service partner. The unit can also send a fire and fault signal to the building’s fire alarm through a standard volt-free contact, so it works with most alarm systems. If the fire suppression has been triggered, it is replaced before the compartment goes back into use. The CoreShelter is a passive locker without these electronics.
Is it safe to allow e-bike battery charging inside a building?
It depends entirely on whether the charging is managed, and most charging in residential and commercial buildings is not. Open outlets in corridors, stairwells and storage rooms put a charging battery on an escape route with no separation, no gas sensing and no automatic cut-off. Charging becomes defensible when each battery sits in its own compartment with gas and temperature sensing, extraction and automatic power shut-off built in. Where a building has usable outdoor space, moving charging outside is simpler and cheaper than engineering the indoor case to the same standard.
Can a landlord or property manager ban e-bike charging in a residential building?
Usually yes in common areas, and it rarely works. A resident told they cannot charge in the shared spaces charges in the hallway or inside their apartment instead, which moves the battery closer to where people sleep rather than farther away. Bans are also starting to run against building rules moving the other way: under EPBD IV, larger new and renovated residential buildings in the EU must be pre-cabled for future charging, including for e-bikes, and provide at least two bicycle parking spaces per home. Cities elsewhere are reaching for certification standards rather than prohibition. The practical position is to provide somewhere safe to charge and then restrict charging everywhere else, because a rule is only enforceable when there is a compliant alternative.
Do battery charging lockers require construction work?
No, and treating them as one is a common way building teams can overspend. ROC Hilversum projected €60,000 to €70,000 for site work, roofing and secure access on a purpose-built outdoor bike facility, then cut anticipated capital expenditure by more than 80 percent by placing two weatherproof units on ground it already had. Lockers need a power connection and a level surface. The one thing that changes the answer is distance from a power supply, since a long cable run means digging after all.
Not sure which setup fits your building? Talk to our team.