The Safe Storage of E-Bike Batteries

E-Bikes and pedelecs have a growing share of sold bicycles, and therefore more households are faced with the question of how to store and charge the E-Bike battery safely, with a focus on adequate fire protection. Because, in addition to the numerous advantages of lithium-ion batteries over the previously common NiCd and lead-acid batteries, these new battery types also carry a number of hazards that require proper storage. The range of possible consequences from incorrect storage of E-Bike batteries extends from power loss to fire and explosion. The following sections cover the most important topics surrounding the safe storage of E-Bike batteries:

• Storage during regular use of the E-Bike
• What provides the best fire protection for E-Bike batteries?
• Storing E-Bike batteries in the home
• Storing bicycle batteries in winter

Storage during regular use of the E-Bike

If you use your pedelec or e-bike daily, the battery often remains on the bike for the entire time, so the battery is charged there between uses. Then completely safe storage of the battery is difficult to guarantee, because if problems occur when the battery is mounted on the bike, adequate fire protection is usually not provided and cannot be provided by suitable storage containers. Regardless of safe storage, you should at least have a suitable battery fire extinguisher ready for emergencies in case the bike battery heats up unusually strongly and a battery danger arises. 

Battery storage while charging away from the E-Bike

Many E-Bike owners store the batteries not on the bike when not in use, but separately, because for example there is no outlet at the E-Bike parking spot or to protect the battery from theft. It is not uncommon for the E-Bike battery to be stored and charged inside the house—in such situations fire protection is absolutely essential. If increasingly powerful bicycle batteries are stored unprotected in the house or garage, the insurance coverage can also be affected. Accordingly, you should rely on suitable storage options that provide sufficient safety in case problems arise and are also practical for daily use and, for example, allow charging. Specifically for this purpose, for example, fireproof battery bags have been developed, which enable safe storage and charging of E-Bike batteries while providing fire protection through a fireproof fabric. Suitable models for different bicycle batteries, such as pannier batteries, frame batteries or power-tube batteries, are available.

What provides the best fire protection for E-Bike batteries?

If you do not mount the battery of your pedelec or E-Bike on the bike but want to store it separately, you quickly face the question of whether a bag or a box is the better choice, and which solution offers the better fire protection. As is often the case, this question cannot be answered universally, because both fireproof battery bags and special storage boxes have advantages and disadvantages. In terms of practicality and fire protection, these two storage options differ - so it’s best to decide based on your personal situation.

Fireproof bags – flexible, but only suitable for one bicycle battery

Bags for E-Bike batteries offer a lot of flexibility in handling and provide a good basic fire protection and are usually somewhat cheaper than battery boxes. It is also possible to charge directly in the E-Bike battery bag, which many pedelec and e-bike owners highly value.

Fire protection when charging the battery

The cables of the chargers can simply be guided through the bag’s closure, so you can store the battery securely in the battery bag during charging. At the same time, the bags are made of fireproof fabric, so a potential battery fire is automatically contained by this material and fire protection is provided. However, if you want to store more than one bike battery, you need additional bags, as most models are designed for a single battery.

Bag should fit the E-Bike battery

The same may apply to battery types: if you change your E-Bike and want, for example, to store a frame battery instead of a pannier battery, you may need to purchase a new fireproof bag because the dimensions of the new bike battery no longer fit the old bag. Another disadvantage can be the lack of impact protection: the fireproof fabric of the bags does not protect the battery from shocks when transporting it or if the battery in the bag falls. Conclusion: Battery bags offer good fire protection for E-Bikes and you can also charge the batteries in them. At the same time they are often designed for only one battery and, for example, suitable for a specific E-Bike battery. 

Suitable bags for bicycle batteries from common manufacturers such as Bosch, Shimano, LG etc.

The fireproof battery bags for E-Bike batteries are suitable for bicycle batteries from common manufacturers and provide a good basic fire protection there - such as Bosch frame batteries (e.g. Bosch PowerTube, Bosch PowerPack, Bosch Dual Battery), batteries from Yamaha, Shimano, Panasonic, Brose, Samsung, LG, Continental, and more.

Boxes for bicycle batteries – good fire protection also for multiple batteries

The different storage boxes for batteries typically consist of two components: a housing made of steel, aluminum, or plastic, and inside this housing fire protection is provided by extinguishing granulate cushions (for example, filled with Pyrobubbles). The E-Bike batteries are stored inside these cushions. If a battery catches fire inside the fireproof box, the extinguishing granulate melts and encapsulates the battery, thereby quenching the fire.

Storage for two or more batteries depending on size

This type of fire protection for battery storage is very efficient and even allows storing multiple batteries inside one box. The storage containers are typically usable for different battery types (pannier batteries, frame batteries, power-tubes / integrated batteries) from common manufacturers (Bosch, LG, Samsung, Continental, Shimano, etc.) as long as the dimensions fit. In conclusion: using extinguishing agents like Pyrobubbles provides reliable fire protection for E-Bike batteries, even for multiple batteries. However, they are usually more expensive to purchase.

Good protection against impacts and external influences

In addition, the storage boxes provide mechanical protection against impacts, because the granulate cushions dampen external influences strongly. Unlike the fireproof battery bags, the bicycle batteries can currently only be charged directly in a few boxes, and price-wise they are somewhat higher than a single bag – but this price difference evens out at the latest when you want to store two batteries and would need two bags, because both E-Bike batteries can be stored in one box.

Boxes for bicycle batteries that can also be charged

New on the market now are two battery boxes that also allow charging E-Bike batteries: the Raclan Box and the Genius Fire Protection Case BSK-1, which are two battery boxes that, in addition to safe storage, also enable charging of E-Bike batteries and are therefore particularly convenient and safe. The Raclan Box additionally has an integrated extinguishing system. If the system detects a temperature rise or smoke gas, it immediately triggers an optical and acoustic alarm. At the same time, the extinguishing system releases an environmentally friendly extinguishing and cooling agent over the E-Bike batteries in case of alarm and thus stops the fire. The resulting smoke-gas mixture is directed into the exhaust management system through filters so that no toxins can escape to the outside. Accordingly, the Raclan Box provides maximum protection, which is reflected in a higher price. The Genius Fire Protection Case BSK-1 is offered without an active extinguishing system but, thanks to the non-combustible inner housing, a special explosion protection and the PyroBubbles® filler cushions, also provides a range of safety mechanisms to store and charge batteries safely.

Storing E-Bike Batteries in the Home

Not everyone has a garage, basement, or another room to store E-Bike batteries when not mounted on the bike or pedelec. Whether to charge the battery, to protect it from theft, or to provide optimal environmental conditions for the winter months—the reasons for wanting to store an E-Bike battery in the home can vary widely. At the same time, you should consider different things, because problems with the battery in a home can quickly have serious consequences. If a fire or even an explosion occurs inside your own four walls, costly property damage and health risks should not be underestimated.

Safe storage of E-Bike batteries in suitable Bags or Boxes

If batteries are to be stored inside a dwelling, you should exercise particular caution and always try to take all necessary and recommended precautions to minimize the risk of dangerous consequences even in case of battery problems. For this, both the storage location and the storage containers are crucial: E-Bike batteries should always be stored only in suitable containers, so-called battery boxes or battery bags. These provide protection for the surroundings and can often prevent worse outcomes in the event of a battery fire by preventing the fire from spreading. Battery bags are made from fireproof fabric, battery boxes are usually a combination of a sturdy case containing, for example, Pyrobubbles or Cirrux cushions, in which the E-Bike batteries are stored. For longer storage, battery boxes are preferable to bags due to higher safety levels.

Fire extinguishers or fire blankets kept for emergencies

If a battery fire occurs inside the dwelling, professional help from the fire department must be called in any case – this is always the first measure in a battery fire. At the same time, quick countermeasures can often reduce the damage. Special battery fire extinguishers and fire blankets for Li-Ion batteries can also be used for E-Bike batteries and thus bridge the time until the fire department arrives and initiate first extinguishing measures. Here you will find details on extinguishing E-Bike batteries.

Never store defective E-Bike batteries in the home

As the preceding explanations show, even seemingly intact E-Bike batteries pose an inherent danger, and appropriate measures to ensure safety should be taken. The danger is even greater with defective batteries: these should never be stored inside a dwelling under any circumstances, as the risks of battery fire or thermal runaway are significantly higher and no one should expose themselves to this risk. If an E-Bike battery is defective—whether it no longer charges, has a mechanical fault (e.g. from a fall), or causes other problems—these must be disposed of immediately by a professional.

Insurance coverage for storing E-Bike batteries in homes

If a fire results from an E-Bike battery stored inside the home, the question of insurance coverage arises: which insurance pays for the damages? Typically, household contents insurance (for damage to your own belongings), the building insurance (for damage to the property/apartment), or liability insurance (if someone else’s property is damaged) may apply. Even if, for example, a tenant causes a fire with an E-Bike battery, usually the building insurance of the landlord pays first and then recourse is taken against the tenant or the tenant's liability insurance. Ensure there is no gross negligence in storage or charging. It is best to check with your insurer before storing an E-Bike battery inside the home—both what storage requirements they impose and what damages are covered by insurance.

Storing Bicycle Batteries in Winter

In winter, E-Bikes are often not used for an extended period, so the battery can be stored for several months. The correct storage is therefore all the more important to prevent damage during the winter months and to be ready to start riding again in spring. If you observe a few things and create the right conditions for winter storage, you are well prepared for the next cycling season and reduce the risks posed by the E-Bike battery.

Store the battery separately from the E-Bike

If the pedelec or E-Bike sits in the garage or is not used during winter, the battery should be removed as far as possible. This gives you more flexibility, prevents unwanted discharge, and spares the bike’s electronics.

Store bicycle battery dry and at 0 to 20°C

After the last use in autumn, the battery should be cleaned if necessary, so it is clean and dry for winter storage. The optimal storage location protects the E-Bike battery from moisture and maintains a temperature between 0°C and 20°C. For example, a frost-protected garage or a suitably dry basement are suitable for winter storage, as could an insulated garden shed.

Pay attention to the correct charge level

During winter storage, the battery should neither be completely discharged nor fully charged beforehand. The optimal charge level for the E-Bike battery is around 30 to 60%, which can be read on many models via a display. With high-quality chargers, you can read the charge level or check it again and establish the optimal charge state if in doubt.

Store in a fireproof battery box

An unattended lithium-ion battery always carries some risk. Even if you consider all the tips above, problems can occur during storage, potentially leading to a fault, fire, or, in the worst case, battery explosion. Although it is rare for a stored battery to become the ignition point for a fire or to explode, a residual risk remains. Therefore, it is advisable to store the battery in a suitable and fireproof battery box for the winter months. These not only protect the surroundings from the dangers but also typically ensure optimal storage conditions for the E-Bike battery.