Quantcast

Power to weight ratio of fuel cells

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

Dusan

Well-Known Member
Joined
Sep 15, 2014
Messages
113
Location
Canada
A lot of people are talking about hydrogen fuel cells for aircraft in order to get over the low specific energy of current batteries, but during my research I've discovered the fuel cell stacks are relatively heavy for the power they can deliver. The best numbers I found for specific power are around 1.5KW/Kg. Does anybody have a better source?
 

Vigilant1

Well-Known Member
Lifetime Supporter
Joined
Jan 24, 2011
Messages
5,320
Location
US
What type of "fuel" are you planning on? Ammonia, methanol, liquid hydrogen, compressed hydrogen? The weight per watt-hour of the fuel will be at least as important as the pounds per watt of the fuel cell.
 
Last edited:

Dusan

Well-Known Member
Joined
Sep 15, 2014
Messages
113
Location
Canada
What is the "best" in the sense what system can get the best power to weight ratio regardless of fuel type?
 

12notes

Well-Known Member
Lifetime Supporter
Log Member
Joined
Aug 27, 2014
Messages
1,113
Location
Louisville, KY
A lot of people are talking about hydrogen fuel cells for aircraft in order to get over the low specific energy of current batteries, but during my research I've discovered the fuel cell stacks are relatively heavy for the power they can deliver. The best numbers I found for specific power are around 1.5KW/Kg. Does anybody have a better source?
50kg (110lbs) for a 75 kW (100hp) power source doesn't seem too heavy to me. If you add a 25 kg(55lb) electric motor*, it's the same installed weight of a 100hp Rotax 912ULS package (including the alternator and everything needed to run the engine) at 75 kg (165 lbs).

* - I don't have time to look up and confirm, but I seem to recall a 75kW motor was available at this weight.
 

Noeson

Member
Joined
Sep 27, 2020
Messages
20

2.0 kW/kg, but that's Toyota. My understanding is it's 10 lbs/kwh for a battery system and 2 lbs/kwh for practical purposes with current tech.

One bare bones system might be a 3kwh fuel cell ($15k) with 100 lbs / 10kwh of batteries ($5k diy?) for takeoff, a pair of Roto Max motors, ($1k) and a 200 lb tank ($1k?) with 6 lbs hydrogen producing a total of 100kwh (assuming efficiency is going to be lower than Toyota). Forklift industry has an infrastructure built up already for generating/pressurizing hydrogen, same with drones:

HYSTAT™15 – Indoor | Hydrogenics
 
Top