Why aren't drones and aircraft using hydrogen-oxygen fuel cells?

[Jarfi]

I've heard they were much more efficient then li-ion batteries and anything else really.. and drones today are all about flight time, wouldn't hydrogen fuel cells result in a great flight time advantage? why are they not in use?

 

[Doug Huffman]

Too low energy density. Expensive storage systems. Expensive fuel. Expensive motor.

 

[donpacino]

Most of the power on aircraft today comes from the engines. The batteries are used as emergency backup in case of a failure, which means that the batteries efficiency are not a major cause of flight time reduction

 

[Jarfi]

Too low energy density. Expensive storage systems. Expensive fuel. Expensive motor.

The motor is an electric motor, they are the same as for normal li-ion batteries.

Energy density of hydrogen gas is yes, large which I must admit, having a gas tank for hydrogen in a drone would certainly make things more expensive I admit.

Most of the power on aircraft today comes from the engines. The batteries are used as emergency backup in case of a failure, which means that the batteries efficiency are not a major cause of flight time reduction

I am not meaning conventional aircraft but electric aircraft as in drones that use electric motors. Hydrogen fuel cells generate electricity from hydrogen and oxygen

 

[donpacino]

I am not meaning conventional aircraft but electric aircraft as in drones that use electric motors. Hydrogen fuel cells generate electricity from hydrogen and oxygen

Wow I am a dummy.
Shows how you can get locked into one idea!

 

[SteamKing]

I've heard they were much more efficient then li-ion batteries and anything else really.. and drones today are all about flight time, wouldn't hydrogen fuel cells result in a great flight time advantage? why are they not in use?

A picture of the last aircraft which used hydrogen in a big way (but not for power):

The Hindenburg​

 

[davenn]

Energy density of hydrogen gas is yes, large which I must admit, having a gas tank for hydrogen in a drone would certainly make things more expensive I admit.

Energy density of hydrogen gas compared to Li-Ion batteries is very low
the batteries give you the "best bang for buck"

Dave

 

[NascentOxygen]

A picture of the last aircraft which used hydrogen in a big way (but not for power):

The Hindenburg

Alas, there's always going to be one passenger who ignores the "No Smoking" sign.

 

[Jarfi]

Energy density of hydrogen gas compared to Li-Ion batteries is very low
the batteries give you the "best bang for buck"

Dave

Yup, Lithium batteries aren't too shabby.. especially the high end ones have mad energy density; http://eu.nkon.nl/rechargeable/18650-size/r-panasonic-ncr18650b-button-top.html this is just mindblowing..

Anyways yeah you guys are right, hydrogen fuel cells are complex and spacey... which is exactly the opposite of what a drone needs, drones have to be as light and neat as possible. It's probably more of a thing for cars, I think a number of electric cars actually this tech