You’re standing at the Delta check-in counter, and the agent asks that one question we all sort of tune out: "Any lithium batteries or power banks in your checked luggage?" Most of us just say "no" and keep moving. But honestly, getting this wrong isn’t just a minor travel hiccup—it’s how you end up with a confiscated 80-dollar charger or, in a much worse scenario, a fire in the cargo hold.
Delta is actually pretty chill about tech, but they are incredibly strict about where those batteries sit. Basically, if it’s a "spare" battery—which is exactly what a power bank is—it stays with you in the cabin. Period.
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The 100Wh Rule: Why Your mAh Number Might Be Lying
Most people look at their power bank and see "20,000 mAh" or "30,000 mAh" and think they’re good. But Delta, the FAA, and the TSA don't care about mAh. They care about Watt-hours (Wh). This is where things get a little technical, but it’s the difference between breezing through security and a headache at the gate.
Most consumer power banks fall under the 100Wh limit. For Delta, any battery under 100Wh is generally fair game in your carry-on. You can actually bring up to 20 of these small ones if you really wanted to, though TSA might give you a funny look.
But how do you know if yours is legal? You’ve gotta do a tiny bit of math if the Wh isn't printed on the back. Take the mAh, multiply it by the voltage (usually 3.7V), and divide by 1,000.
- 10,000mAh is about 37Wh. Totally fine.
- 20,000mAh is about 74Wh. Still safe.
- 26,800mAh is usually the "sweet spot" at 99.2Wh. This is the biggest you can carry without asking anyone for permission.
If you’re rocking one of those massive bricks meant for a MacBook—something like a 30,000mAh or 40,000mAh unit—you’re likely crossing into the 101-160Wh zone. Delta allows these, but there’s a catch: you’re limited to exactly two per person, and you technically need "airline approval." In reality, for domestic flights, as long as it’s clearly labeled and in your carry-on, you’re usually fine, but it’s always smarter to check in at the desk. Anything over 160Wh? Leave it at home. It’s not getting on the plane.
Never, Ever Put It in Your Checked Bag
This is the rule that causes the most drama. You might think, "It’s safer in my suitcase away from everyone," but it's the exact opposite. Lithium-ion batteries have a tiny, tiny chance of doing something called "thermal runaway"—basically, they catch fire and won't stop.
If that happens in the overhead bin, the flight attendants have specialized fire bags to handle it. If it happens at 35,000 feet in the cargo hold? No one can get to it.
This rule also applies if you’re at the gate and Delta tells you there’s no more room for carry-ons. If they "gate-check" your bag, you must pull that power bank out and keep it in your pocket or a small personal item. If you forget and the plane takes off, you’ve technically violated FAA safety regs.
Smart Luggage: The Delta Dealbreaker
Delta was one of the first airlines to get really aggressive about "Smart Bags." You know, the suitcases with built-in chargers?
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- If the battery is removable, you can check the bag, but you have to carry the battery into the cabin.
- If the battery is permanent, Delta won't even let the bag on the plane. Not even as a carry-on.
Practical Tips for Your Next Flight
- Check the label: If the "Wh" or "mAh" text is rubbed off or unreadable, security has the right to take it. They can't guess the capacity, and they won't risk it.
- Protect the terminals: If you’re carrying spare batteries (not in a power bank casing), put them in a small plastic bag or tape the ends. Short circuits happen when a rogue penny touches the battery contacts.
- Keep it accessible: Don't bury your power bank at the very bottom of your "personal item." You’ll likely need to pull it out at the security bin, or worse, quickly if the crew sees smoke.
- Don't charge it on the plane: While you can use your power bank to charge your phone, Delta (and the FAA) generally says you shouldn't be recharging the power bank itself using the plane's seat power.
Before you head to the airport, just flip your charger over and look for that "Wh" number. If it says anything under 100, you’re golden. If it’s between 100 and 160, just make sure you only have two and they stay in your hand.
Actionable Next Steps
To stay fully compliant, check the physical casing of your power bank right now. If the text is fading, use a piece of clear packing tape to protect the specs from being rubbed off by your bag's lining. If you own a high-capacity power bank over 100Wh, print out Delta’s official battery policy from their website and keep it in your laptop sleeve—it’s a lifesaver if you encounter a gate agent who isn’t quite sure about the 160Wh allowance. Finally, ensure your power bank is charged to less than 30% if you are flying internationally in 2026, as new global shipping and safety standards are increasingly leaning toward lower "State of Charge" requirements for lithium transport.