FAA 100 W Lithium battery limit

[Meshka7]

Does anyone know where this limit comes from? Basically you can't carry more than 100 W Lithium batteries (including chargers). Unless you get permission from the airline and you are then limited to a maximum of 2 and not in checked bags. I can't find the source of this limit and what's the FAA trying to accomplish? Is 100W for example not very explosive? Are they trying to prevent malicious tampering with the Airplane electronics? Any idea?

[nctnico]

Lithium batteries may iginite spontaneously. If this happens in a suitcase in the cargo hold then the plane could get on fire. It is easier to contain in the passengers cabin because it is easier to notice. The power limit is to limit the amount of energy that can be released in an event so the fire can be put out by the cabin crew by pouring water over the battery pack or submerging the battery pack in water.

[Domagoj T]

A 100 Wh battery is quite big one (for example. DJI Phantom 4 battery is 90 Wh and weights in at 470 g). Average traveler doesn't carry batteries much bigger than that (laptop batteries being in the ballpark) so the regulation is not much of a hindrance. Do you have some portable device that uses bigger batteries than that? I'm not sure I've seen any.

[Rerouter]

The limit is for over 100Wh per battery, you can have a large number of those sub 100Wh batteries provided they are packed suitably (generally in a flame proof bag or enclosure)

e.g. you fly a quadcopter? well you can have a backpack full of 95Wh batteries, provided each is packed suitably, you will probably have it inspected, but it should get through no issue.

I face the same thing with cordless drill batteries, can carry as many as I like, so long as each battery is under the limit. (and the terminal area is taped over)

https://www.faa.gov/hazmat/packsafe/more_info/?hazmat=7

[john61ct]

Yes that's a "per unit" limit.

But the number of units is not stated, up to the discretion of the officer.

I doubt if a half-dozen would be refused.

I doubt two dozen would be allowed.

Putting them all in a special container may well reduce the number, IMO better to have a few here a few there but not making it obvious you're trying to be deceptive.

Check out Grin's modular LiGo battery