Electric Paraglider Battery Specs?

Hey Guys,

I own a custom high powered battery building business and am looking for expanding into the local Israeli electric paragliding scene as they have the need for a high powered yet light wait battery packs.
I googled and didn't find much information of common battery specs for these things.
I would like to know what are is the voltage range the use and common power output (takeoff and cruise outputs) they require.
Also would like to know what is an acceptable weight for a battery pack.

you need about 15kW to match petrol.
so 15kW needs a serious motor and a even more serious battery.
do the math on a 96V motor, you get 150A sustained!
running that power for 1 hour would need a 70KG battery at least.

no way a paraglider will swap 30ish KG petrol motor for a 100+KG pack with a electric motor.

if i remember they already had a startup making these things a few years ago. doubtful they stil exist.

flippy said:

you need about 15kW to match petrol.
so 15kW needs a serious motor and a even more serious battery.
do the math on a 96V motor, you get 150A sustained!
running that power for 1 hour would need a 70KG battery at least.

no way a paraglider will swap 30ish KG petrol motor for a 100+KG pack with a electric motor.

if i remember they already had a startup making these things a few years ago. doubtful they stil exist.

Click to expand...

There are many kits for this in google so it's not a thing that doesn't exist.
Of course the added weight is terrible but I would prefer the extreme weight I have to hold with my back and legs for a minute until takeoff than to tolerate the motor making me deaf the whole flight.

The question is if 15kW continuous are really necessary.
During take off in a flat area it is certainly a good thing, but otherwise i think it is a bit on the high side for a paraglider.

problem is that you need to take the max power as a real thing. if you are going to commericaly sell it then you are going to get some idiot consumer that will just run the prop full bore all the time.

in order to prevent damage you are needing a very expensive controller like a sevcon to prevent battery damage by regulating the power profiles by motor and battery temperature for example. those controllers are 1000+ USD a pop new. you cant have a bms just shutting down the power due to overheating. you need reduced power and limp home modes.

Do you have any idea what kind of voltages these guys usually run?
15kw is 150A @ 100V!

The numbers are not insane actually.
If you take a 28S (103.6V nominal) at 15P (37.5Ah for Samsung 25R) you will draw 150A and use half the discharge rate of those cells (4C out of 8C) making sure the pack will not be under unhealthy stress even at constant 150A.
Also, 103.6V * 150A = 3900Wh which means 15 minutes at 15kw BUT if you use only about 8kw after takeoff then I think it will be about 25 minute flight per 3900Wh which means a 20kg pack which is not bad.

Do you have any idea what is the weight of a gas system compared to an electric system not including the battery?

You need a takeoff / temporary power rating and continuous probably. Otherwise there will be no endurance.

It definitely doesn't need 15kw for steady state flight.

For the battery go for energy density over power density for max energy / weight. You will have good cooling.

I can weigh in on this topic a little bit as I fly paragliders as well as paramotors (powered paragliders).

I currently own a 200cc Nirvana Rodeo unit and also second unit no name brand with a twin cylinder 200cc DLE engine in it.

The Nirvana weighs 34kg with full fuel (10litres)

The DLE is considerably lighter...about 26kg with fuel (holds less fuel and the unit itself is also about 6kg lighter than the nirvana )

The big issues for me are

1. thrust and how much one needs is heavily dependent on the wing and obviously pilot weight. My Nirvana puts out a lot of thrust...in the order of 65-70kg of it.

2. Flight time...with 10ltrs of fuel on board i fly for about 3 hours on average.

In terms of electric...it simply has to be a lot lighter or it's a waist of time. Some of the guys I have heard about who investigated electric love the lightweight but are very restricted by flight time...I have heard 15-25 minutes at best.

Finally one important thing...paragliders have accelerator systems. With powered paragliding wings, this system is comprised of a foot control (speedbar) and hand control (trimmers). On a reflex wing type (which the best powered wings are), activating speed system will quite often use all of the available thrust an engine can produce to maintain level flight, unless the unit is way over powered for the weight it's carrying. The reason for this is the dramatic increase in speed with full speed system engaged...on a lot of wings these days it increases from about 40km/hr to 65km/hr and on higher performing wings, up to 80km/hr...so it can be a massive increase in propeller rpm and thrust in order to achieve this. One may ask why engaging speed system on a wing should matter...because engaging speed system dramatically increases sink rate in order to also allow the wing to fly significantly faster. Paragliders only climb or descend by varying speed through the air. So you can't increase speed without also changing sink rate to overcome the tendency to climb...achieved by altering the wing angle and shape (hence the two types 1. speedbar - alters Angle of Attack and 2. Trimmers - alters wing shape)

I think the speed system is the real killer for electric...this severely limits the scope of wing types available and what pilots can do. Flying fast means high propeller rpm....rapid current draw on the batteries. This means heavier battery pack...which ends up being of no advantage over petrol engines...especially when one also considers flight time.

Ideally I would say this, electric needs the following min capabilities...
1. At most 20kg unit
2. Absolute minimum of 45min to 1 hour flight time at about 1/2 - 2/3 throttle
3. Thrust of 40-50kg at full throttle
4. Cruise speed of about 40km/hr at about 1/2 throttle

Until those goals can be achieved as an absolute minimum, they are pointless.

I'm guessing it's a problem then as a 4000Wh is about 20kg of battery only and can provide, well, 4000W an hour which I'm guessing that even cruise will consume more than that? Am I right?

7~10kW is needed on average.

Check out www.openppg.com. It's an open source electric paramotor. Not sure how much power they are putting out, but they claim up to 1 hour flight time.