As a drone enthusiast who devotes a lot of time to being informed about my ‘hobby’, I get to learn a great deal about the technical side of the business, like the characteristics of Lithium Polymer(LiPo) batteries.
What Makes LiPo Batteries ‘Dangerous’
If you google Lithium batteries you’ll see lots of information on both Lithium Ion and Lithium Polymer batteries. They’re essentially almost the same thing, as LiPo batteries are actually “Lithium-ion Polymer” batteries.
Lithium-polymer batteries are almost exactly the same as lithium-ion batteries, but they are instead contained in a flexible polymer casing. Here’s a disassembled Mavic battery showing the soft-sided polymer cells contained inside.
What makes LiPo batteries dangerous is that they can become unstable and overheat and/or explode. Worst case scenario is that they burst into flames. In the cargo hold of an aircraft a battery fire could spread so quickly that it might overpower existing fire-suppression systems.
As a frequent air traveler, I can tell you that ISIS and airline food aren’t the things that make me nervous in the air; but Lithium batteries stowed improperly in the cargo hold does.
Check Your Airline Rules
There are basic best-practices that every responsible drone pilot should be following when travelling with LiPo batteries.
First, it’s common sense that LiPo batteries are never put into checked bags. Ever. But I’m always surprised when I read the forums just how many people have no idea that this is a requirement on every airline.
Next you should be storing your loose LiPo batteries in a protective bag, regardless of whether the airline requires you to.
Airlines work together to vet rules and develop common practices through the International Air Transport Association (IATA), and they regularly update their Guidance Document to maintain compliance with Dangerous Goods Regulations.
The important takeaways from the 20 page Guidance Document (currently edition 58) are as follows:
- Lithium batteries must not be transported at a state of charge above 30%
- Lithium batteries are forbidden for transport as cargo (meaning checked bag) on passenger aircraft
One of the major risks associated with the transport of batteries and battery-powered equipment
is short-circuit of the battery as a result of the battery terminals coming into contact with other
batteries, metal objects, or conductive surfaces.
Packaged batteries or cells must be separated in a way to prevent short circuits and damage to terminals. They must be packed in a strong rigid outer packaging unless when contained in equipment, the battery is afforded equivalent protection by the equipment in which it is contained.
IATA recommends that individual batteries in non-conductive material such as a plastic bag, and separating or packing batteries in a manner to prevent contact with other batteries, devices or conductive materials.
Most importantly, exposed terminals or connectors must be protected with non-conductive caps, non-conductive tape or by other appropriate means.
The Power Management section on our Parts & Accessories page provides links to various LiPo protective bag suppliers. Most LiPo bags are reasonably priced and some are even designed for your specific DJI product. But they’re of no use if you don’t use them.
Check Your Airline
Being proactive and using LiPo bags and contact covers shows you’re knowledgeable and responsible in the transport of your batteries to airline staff.
Each airline has it’s own rules so it’s mission critical that you check your airlines website to ensure compliance with their rules.
Here’s an example using Delta Airlines:
Like all airlines, Delta’s website has a specific page devoted to Dangerous Goods, with a specific section on Lithium Batteries. From Delta’s website we can see the following rules for Lithium batteries:
- Pack spare batteries in carry-on baggage.
- Keep spare batteries in the original retail packaging to prevent unintentional activation or short-circuiting.
- If original packaging is not available, effectively insulate battery terminals by isolating spare batteries from contact with other batteries and/or metal.
- Specifically, place each battery in its own protective case, plastic bag or package, or place tape across the battery’s contacts to isolate terminals.
- Take steps to prevent crushing, puncturing, or putting a high degree of pressure on the battery, as this can cause an internal short circuit, resulting in overheating.
Delta also has specific size limits for Lithium batteries, prohibiting any battery larger than 160 watt hours (Wh) from being allowed on board any aircraft.
Using the Mavic Intelligent Flight Battery as an example, how does that translate?
The Mavic battery specs are listed on the DJI website, as they are for the Spark, Phantom 3, Phantom 4, Inspire, Matrice, Agras, and S1000.
DJI tells us the Mavic battery has 43.6 Watt-hours, placing it well below Delta’s 160 Wh limit.
If your device doesn’t specify it’s Watt-hour rating you can calculate it yourself by multiplying Volts x Milliamepere-hours (mAH). The Mavic uses an 11.4 Volt battery with 3830 mAH, so you would work it out as follows:
(Volts X mAH)/1000 = Watt Hours
(11.4 X 3830)1000 = 43.6 Wh
As you can see, our math jibes with what DJI is telling us about the Mavic battery.
Remember that all of the responsibility to know and follow the rules regarding Lithium batteries is yours.
If you’re a drone pilot, or plan to be one, read and understand your owners manual. Learn from the experiences of other pilots in meet-ups or online groups, and share what you have learned as well.
With increased scrutiny on all aspects of the lifestyle associated with drones, we need sharp, informed pilots who support the longevity of our hobby by their responsible actions.