# How to Check If a Power Bank Is Allowed on a Flight

Having some extra juice for your phone is always handy, especially when you’re about to land in a new city or country. However, if you’re planning on bringing a power pack or some extra batteries on the plane, you should probably check their specs first: not everything flies. Carrying extra-large power banks or lots of smaller ones may be a bit risky for the plane, especially if the batteries are in the cargo hold area where fires can’t be managed as easily.

If you already have a good idea of what Wh’s and mAhs are, you can jump down to the flowchart for a quick guide.

If you are curious to know if a power bank is allowed on a flight, the answer is yes, though it is not so straightforward.

## Location, location, location

The rule here is simple: if you have a power bank, laptop battery, phone battery, or anything else that uses a rechargeable lithium-ion battery, it goes in your carry-on. It might seem strange, but it’s actually safer to keep these potentially explosive devices where they can be monitored. Having a phone catch fire in the cabin is a little frightening, but it could be far worse in a cargo hold where no one can readily notice and stop the fire before it spreads.

## Go small or go home

Putting your batteries in your carry-on is easy enough, but that might not be enough to get you past security if you’re packing an energy source that could power a small village. Most power packs are generally under the 100 Watt-hour (Wh) limit, but it’s a good idea to check anyway.

You may have noticed that your power pack doesn’t measure its output in Watt-hours – it probably uses milliamp hours, or mAh. Many power packs also have the Watt-hours listed somewhere, but in case they don’t, here’s the formula to convert between units:

1. Find the mAh number (probably between 1 and 30,000)

2. Find the voltage (usually 3.6V/3.7V)

3. Divide the mAh number by 1000, converting it to Amp hours (Ah)

4. Multiply the Ah number by the voltage to get the Watt-hours.

The whole formula:

For example, a 20,000 mAh power pack with a 3.6V rating would be: (20,000 / 1000 ) * 3.6 = 72 Watt-hours.

While power packs come in a variety of power ratings and voltages, an average 3.6V power pack would have to be around 28,000 mAh before it went over the 100 Wh limit. As long as you see “3.6V” or “3.7V” and a number lower than 28,000 mAh, odds are good that your battery is plane-friendly.

## Going big without going home

However, if you do happen to have a bigger power bank, there’s still a good chance you can bring it along with you. Batteries that are rated from 100.1 – 160 Wh just require airline approval to be brought on board a plane. There isn’t really an established procedure for flying with these batteries, so you probably won’t see it as a luggage option, but calling your airline and asking a representative will get you the answer you need.

For reference, 160 Wh is roughly equal to 44,000 mAh at 3.6 volts.

Anything bigger than 160 Wh could cause you some problems, as it has to follow the guidelines for dangerous cargo. Luckily, it’s pretty difficult to find a power bank over that limit, and if you have one, you would probably know it.

## The flowchart

If you just need a quick reference, here’s a flowchart:

## How dangerous are they really?

If you accidentally took an oversized battery on a flight or left one in your checked luggage, it isn’t likely to cause a catastrophe, but there is a non-zero chance of disaster. A quick search for “exploding battery on plane” will bring up plenty of cases, though generally these fires have been quickly extinguished.

The only confirmed battery-related disaster was a UPS plane in 2010 which crashed at Dubai International Airport after a fire caused by a cargo of lithium batteries. This crash is a major part of why restrictions on passengers carrying lithium batteries exist, and UPS now carries this kind of cargo in special fiberglass containers.

There is even an (unsubstantiated) hypothesis that a cargo of lithium-ion batteries was responsible for the disappearance of MH370 in 2014.  While there’s not much cause to freak out for the average passenger, you may as well do your part to make sure that your plane makes it safely to its destination.

## Final Checklist

Ultimately, all you need to know to avoid any power mishaps while flying is:

1. Keep your batteries in the cabin
2. Don’t take batteries over 100Wh (usually about 27-28,000 mAh) without consulting the airline

Armed with those two pieces of information, you should be able to have a nice relaxing flight in your high-speed metal tube flying several kilometers above the ground.

Andrew Braun

Andrew Braun is a lifelong tech enthusiast with a wide range of interests, including travel, economics, math, data analysis, fitness, and more. He is an advocate of cryptocurrencies and other decentralized technologies, and hopes to see new generations of innovation continue to outdo each other.

1. Your flowchart seems to have a mistake in the workflow to calculate Wh. You say find the mAh, find the Voltage, then you say to divide by 1000, and then you say to multiply the mAh and Voltage. I think those last two boxes need to be switched.

1. The math is correct but the description is incorrect. The number used in the second box is actually Ah, not mAh.

1. Good eyes! Yes, it looks like I swapped the order of operations between the text walkthrough of the equation and the flowchart walkthrough. It still works out to be the same number, but it’s definitely a bit confusing if you read the first set of instructions and then see the flowchart.

And of course when a milliAmp is divided by 1000, you lose the “milli” prefix and are left with just “Amp,” so it should technically be Amp hours. I’ll get that reworded with a parenthesis to explain why the notation is changing. The notation mistake may stick around in the flowchart for a bit, though; it’s somewhat harder to get edited on the fly. For the same reason, I’ll probably leave the disparity between equations; it’s just two different ways to get the same number–the step-by-step list is easier with a calculator, while the flowchart method may be a little easier to get in your head since you’re dividing a larger round number by 1000 and then multiplying. I think I also made some capitalization mistakes here and there with some terms–turns out I’m more qualified as a frequent traveller than as an electrical engineer :D

Thanks for the help!

1. USB is 5 Volts. Is the mAh rating at a different voltage than the output voltage? I know phone batteries are usually nominally around 3.7V (though they can be higher when fully charged,) but USB is 5V.