What to Know Before You Buy an E-Bike Battery Bag

Experts say e-bike battery bags may do the one thing they're supposed to do—stop a fire. Here's how to stay safe when handling an e-bike battery.

By Justin Krajeski
Home & Tech Writer

August 22, 2026

Many battery bags lack the necessary safety certifications. Here, Mike Sedlak—who leads Consumer Reports' e-bike testing—places the battery from a Segway Muxi e-bike into the Zeee Fireproof Large Capacity Battery Storage Bag.

Photo: Scott Meadows/Consumer Reports

If you own an electric bike with a removable lithium-ion battery, you might have considered purchasing a separate battery bag. These vessels are designed to safely store or transport the battery when it’s not in use. And at first glance, battery bags seem like a logical solution to minimize the risks associated with battery fires (a phenomenon that, while relatively rare, has been on the rise worldwide).

The trouble is, there’s no guarantee that the battery bag you buy (or already own) will actually contain a fire or stop it from spreading. We spoke with other sources and phoned more than 3 dozen bike stores and outside experts, and found that the general consensus is that e-bike battery bags, by and large, lack necessary safety certifications. There are also concerns that many bags may not be large enough to contain an e-bike battery experiencing thermal runaway, during which the battery releases gases that must be contained.

In this article

Problems With E-Bike Battery Bags
How to Stay Safe When Handling E-Bike Batteries

Problems With E-Bike Battery Bags

Many of the problems linked to e-bike batteries stem from the battery going into thermal runaway. That’s when a battery enters an “uncontrollable self-heating” state that can result in extremely high temperatures, smoke, and fire, for example, due to external heat. A battery bag should, theoretically, help keep the event contained, “so no toxic smoke, flame, or fragments would be released,” says Simon Jones, chief engineer and head of the Energy Innovation Centre at the University of Warwick’s Warwick Manufacturing Group in England.

But Jones and other experts doubt whether a typical battery bag would do that. “E-bike batteries are big,” Jones says. In some cases, the batteries are actually quite a bit bigger than the bags designed to hold them. For example, we compared the dimensions of an extra battery pack for the Lectric One—a top-rated Class 2 e-bike in our lab tests—against the claimed dimensions for these popular e-bike battery bags from Zeee and Tamfile. Neither bag would be large enough to hold that common battery. We found the same issue with a number of the bags and batteries we compared. That disconnect may stem from the fact that many battery bags are made by third-party manufacturers and aren’t specific to any particular model.

Even when a battery bag is large enough to hold a healthy battery, Jones says it’s unlikely that the same bag could contain the plumes of gas emitted by the battery if it were to malfunction. “I very much doubt that a bag of a reasonable size can contain an e-bike battery in a thermal runaway,” he says. “I fear that bags could be sold that create a false sense of security, but do not work, and they may put people into more danger, not less,” he adds.

Another issue with e-bike battery bags is that none of the bags we surveyed carry safety certifications from a nationally recognized testing laboratory, such as UL Stolutions, an independent safety organization. This is significant. “For products like this, an independent test and certification scheme is essential,” Jones says.

“I don’t believe any of the battery bags you’re likely to find online will give much containment to a real e-bike battery fire. The amount of heat and pressure that can build up is just too much to contain in a soft-sided bag. Could it slow things down? Perhaps,” says Brian Morin, the CEO of Soteria Battery Innovation Group, a Greenville, S.C., company focused on lithium-ion battery safety. But there’s really no way to say until it’s potentially too late.

How to Stay Safe When Handling E-Bike Batteries

UL Research Institutes shared tips on selecting, caring for, and disposing of lithium-ion battery-powered devices as part of its Take C.H.A.R.G.E. of Battery Safety campaign.

We also spoke to Jason Holmes, CR’s director of lab operations and an avid e-bike user, and Lee Hershberger, owner and chief operating officer of Brimstone Fire Protection, a company dedicated to tackling the challenges posed by lithium-ion battery fires. They offered more safety tips and an alternative to e-bike battery bags: heavy-duty blankets. More on that, below.

Look for e-bikes that are listed or safety-certified. E-bikes can be certified by a nationally recognized testing laboratory, such as UL Solutions, which ensures they meet important safety requirements. Specifically, UL 2849 examines the safety of e-bike electrical and charging systems.
Handle your lithium-ion battery-powered device with care. Follow the manufacturer’s instructions. Use only the charging equipment that comes with the product, and store the battery away from extreme temperatures, direct sunlight, and any flammable materials.
Charge your e-bike outside the home whenever possible. Don’t charge your e-bike overnight. Overcharging can cause the battery to catch fire during a thermal runaway event.
If you do need to charge your battery indoors, make sure it’s not in your exit path in the event of a fire. Adam Barowy, principal research engineer at UL Solutions, says, “We always recommend that people charge products with larger batteries, like micromobility devices, away from their exit path, so that if something does go wrong, they can get out quickly.”
Check your e-bike during charging. Holmes abides by UL’s recommendations: He primarily charges his e-bike in the bike room at CR’s office, which is an easy place for him to check his e-bike in between meetings. At home, Holmes charges his e-bike in a detached garage.
Inspect your battery periodically. Particularly if you get into an e-bike crash, inspect your e-bike’s battery to make sure that there aren’t any obvious scratches. If it is damaged, replace it, Holmes advises.
Recycle properly. If your e-bike battery needs replacing, you should recycle the old one at a battery recycling center. Don’t throw it into a regular trash can. Holmes’ first e-bike battery had 7,000 miles on it, and its charge began to fall below 20 percent after completing half of his daily commute. After dropping it and noticing a crack in the battery, he replaced and recycled it. In addition to checking stores like Best Buy, Home Depot, and Lowe’s for drop-off locations to recycle your lithium-ion battery, Holmes recommends recycling your e-bike battery with local household hazardous waste programs or state electronic waste collection sites.
Have the tools to contain a fire. Hershberger of Brimstone Fire Protection recommends using heavy-duty blankets instead of a battery bag to proactively cover a stored battery, or to reactively contain a thermal runaway event. The blankets he sells are large enough to fit an e-bike battery under them, ranging from 5x6 feet to 16x6 feet.
Keep fire extinguishers on hand, but know their limitations. A typical fire extinguisher may not help with an e-bike battery fire, but a combination fire extinguisher is good to have at home for other types of fires. “Should an e-bike battery fire occur, evacuate and call 911,” says Bernie Deitrick, who leads CR’s testing of fire extinguishers.

Justin Krajeski

Justin Krajeski is a reporter covering a range of travel and healthy-living topics, including e-bikes, treadmills, exercise bikes, and ellipticals. Before joining CR in 2022, he covered style for Wirecutter, part of The New York Times, where he began working in 2015. Justin lives in Brooklyn, N.Y.