Are 18650 Batteries Allowed on Planes? The Definitive Guide

Are you planning a trip and wondering if you can bring your 18650 batteries on the plane? I’ve been there.

As someone who travels with photography gear and flashlights that use 18650 batteries, I’ve had to navigate these rules multiple times. Are 18650 batteries allowed on planes? The short answer is yes, but there are some critical restrictions you need to know about.

In this comprehensive guide, as a professional 18650 battery pack manufacturer, I’ll break down everything you need to know about flying with 18650 lithium-ion batteries in 2025. You’ll learn the exact rules, how to pack them safely, and how to avoid any issues at security.

Let’s dive in.

What Are 18650 Batteries?

Before we get too far, let’s clarify what these batteries actually are.

18650 batteries are rechargeable lithium-ion cells that measure 18mm in diameter and 65mm in length (hence the name “18650”). They typically have a voltage of 3.7V and capacity ranging from 1800mAh to 3500mAh.

You’ll find these cylindrical powerhouses in a variety of devices:

• High-powered flashlights and headlamps

• Laptop battery packs

• Power banks and portable chargers

• Electric bikes and scooters

• Vaping devices

• DIY electronics projects

Their popularity comes from their high energy density and reliability. But these same properties also make them a potential safety concern for air travel.

Are 18650 Batteries Allowed on Planes

The short answer: Yes, but with important restrictions. The most important rule? Spare 18650 batteries must be in your carry-on luggage only. They are strictly prohibited in checked baggage.

Why this distinction? If a battery were to short-circuit or overheat in the cargo hold, flight crew couldn’t access it to handle the situation. In the cabin, any issues can be addressed immediately.

But there’s more to know than just this basic rule.

Official Aviation Regulations for 18650 Batteries

Let’s look at what the official rules say about traveling with lithium-ion batteries like 18650s.

FAA and TSA Guidelines

According to the Federal Aviation Administration (FAA) guidelines updated for 2025:

• Lithium-ion batteries (like 18650s) with 100 watt-hours (Wh) or less may be carried in carry-on baggage

• Spare batteries must NEVER be in checked luggage

• Terminals must be protected to prevent short circuits

• Batteries installed in devices can go in either carry-on or checked baggage

The Transportation Security Administration (TSA) regulations align with the FAA on these points.

International Air Transport Association (IATA) Rules

The IATA, which provides guidelines for international flights, has very similar rules. Their 2025 Dangerous Goods Regulations state:

• Lithium-ion batteries under 100Wh are permitted in carry-on luggage

• Each person is limited to a maximum of 20 spare batteries (though airlines may approve more)

• Batteries between 101-160Wh require airline approval, with a limit of two spares per person

Calculating Watt-Hours for Your 18650 Batteries

This is important: you need to know the watt-hour rating of your batteries.

Here’s the simple formula:
Watt-hours (Wh) = Voltage (V) × Capacity (Ah)

For a standard 18650 battery rated at 3.7V with 3500mAh (3.5Ah) capacity:
3.7V × 3.5Ah = 12.95Wh

Good news: Most 18650 batteries fall between 7-13Wh, well below the 100Wh limit. This means they’re generally allowed without special permission.

Carry-On vs. Checked Baggage: The Critical Difference

Understanding where you can pack your batteries is crucial for hassle-free travel.

Carry-On Rules

For your carry-on luggage:

• You can bring spare (uninstalled) 18650 batteries

• Batteries must have protected terminals to prevent short circuits

• Most airlines allow multiple batteries under 100Wh for personal use

• Devices with 18650 batteries installed are also permitted

As one traveler on Reddit reported: “You can carry up to 20 spare batteries in your carry-on luggage, none of which may be over 100WH so long as they are packed in a way to prevent short circuits.”

Checked Baggage Rules

For checked luggage, the rules are much stricter:

• NO spare or loose 18650 batteries allowed

• Devices with batteries installed can go in checked luggage IF they’re completely powered off

• The device must be packaged to prevent accidental activation

The FAA explicitly states: “All spare lithium batteries and power banks must be removed from the bag and kept with the passenger in the aircraft cabin.”

How to Properly Pack 18650 Batteries for Air Travel

Proper packing is essential for safety and compliance. Here’s how to do it right:

Protecting Battery Terminals

You must prevent the battery terminals from touching metal objects (which could cause a short circuit). Use one of these methods:

1. Original packaging: Keep batteries in their retail packaging if possible

2. Terminal covers: Use plastic caps designed for 18650 batteries

3. Electrical tape: Cover the positive and negative terminals with non-conductive tape

4. Battery cases: Store in dedicated plastic battery cases (highly recommended)

5. Individual bags: Place each battery in a separate plastic bag

The FAA specifies: “Battery terminals (usually the ends) must be protected from short circuit (i.e., the terminals must not come in contact with other metal).”

Battery Cases and Carriers

I strongly recommend investing in a proper battery case. These plastic containers:

• Keep batteries organized

• Provide excellent terminal protection

• Make it easy for security to inspect your batteries

• Prevent batteries from bouncing around in your bag

These cases usually cost less than $10 and can save you a lot of headaches at security.

For Devices With Installed Batteries

If your flashlight, laptop, or other device has 18650 batteries installed:

• For carry-on: No special preparation needed, but consider removing the battery if it’s easily accessible

• For checked bags: Ensure the device is completely powered off (not sleep mode)

• Consider padding the device to prevent accidental activation

Real-World Tips From Frequent Travelers

Reading through experiences from other travelers, I’ve collected some practical advice:

Security Checkpoint Strategies

• Be proactive: Remove battery cases from your bag and place them in the security bin

• Know your battery specs: Security agents might ask about watt-hour ratings

• Bring documentation: Having the original packaging or spec sheet can help if questioned

• Stay calm and cooperative: Security is just doing their job

One traveler noted: “I’ve never had a problem. I just flew to Montana and back last weekend. I had 4 lights with me, all with Li-Ion batteries in them. Plus another 18650 and a 21700 in a PB2S power bank charger. All of that in my carryon. Didn’t even get asked about it.”

International Considerations

Different countries may have slightly different interpretations of the rules:

• European countries generally follow similar guidelines to the US

• Some Asian countries may be stricter about battery inspection

• Always check airline-specific policies for international flights

As one international traveler shared: “I’ve regularly traveled within Europe and Asia with flashlights and loose 18650 cells in my carry-on bag and never received even a comment about it.”

Common Questions About Traveling With 18650 Batteries

Let’s address some frequently asked questions:

How Many 18650 Batteries Can I Bring?

Most airlines follow the IATA guidance allowing up to 20 spare batteries under 100Wh per passenger. However, individual airlines may have their own policies, so it’s worth checking with your specific carrier.

What If Security Questions My Batteries?

Be prepared to explain:

• What devices they power

• Their watt-hour rating (show that they’re under 100Wh)

• How you’ve protected the terminals

Having the original packaging or a printout of the battery specifications can be helpful.

Can I Use Power Banks With 18650 Batteries During Flight?

Yes, most airlines permit the use of power banks during flight as long as they’re under 100Wh. However, some carriers may have specific restrictions against charging larger devices or using power banks during certain flight phases.

What About Damaged Batteries?

Never travel with damaged, dented, or swollen batteries. If a battery becomes damaged during your trip, inform airline staff immediately and do not attempt to transport it further.

Safety Considerations and Best Practices

Understanding why these rules exist helps emphasize their importance.

Why These Restrictions Exist

Lithium-ion batteries can undergo a process called “thermal runaway” if damaged or short-circuited. This can lead to fire or even explosion. In a pressurized aircraft at 35,000 feet, this is obviously a serious safety concern.

The FAA notes that “Lithium-ion batteries are required to undergo safety testing. All lithium-ion batteries are capable of overheating and experiencing a process called thermal runaway.”

Additional Safety Tips

Beyond the required regulations, consider these best practices:

• Inspect all batteries before travel for damage

• Don’t store batteries in extreme temperatures (like a hot car)

• Purchase only from reputable manufacturers

• Bring only the batteries you’ll actually need

• Consider discharge level (50% charge is ideal for storage)

What To Do If You Notice A Problem

If you notice a battery becoming hot, emitting smoke, or exhibiting any unusual behavior during travel:

1. Alert flight attendants immediately

2. Do not attempt to handle a malfunctioning battery yourself

3. Follow crew instructions precisely

The Bottom Line: Travel Smart With 18650 Batteries

Let’s wrap this up.

Yes, 18650 batteries are allowed on planes, but you need to follow the rules:

1. Carry-on only for spare batteries

2. Protect the terminals to prevent short circuits

3. Know your batteries’ watt-hour rating (most 18650s are around 10-13Wh)

4. Pack in proper cases for organization and safety

5. Check with your specific airline before traveling

By following these guidelines, you should have no issues traveling with your 18650 batteries. The regulations might seem strict, but they’re in place for everyone’s safety.

Planning ahead and properly packing your batteries will ensure you have power for your devices without any airport hassles.

So, are 18650 batteries allowed on planes? Yes—with the proper precautions, you can bring them along on your next adventure.

Have you traveled with 18650 batteries? I’d love to hear about your experiences in the comments below!