Power Rating and Energy Consumed while in Cruise

[priyank_sai]

Greetings,

If any one knows about approximate power required during cruise phase as a function of speed please let me know?

I found online 175 W for hover but NOT sure if this is correct.

Thanks

 

[With The Birds]

The phantom 4 battery is 83wh. Hover from a full pack to 10% critical level with 175w consumption would give you 25 mins in the air. The 175w figure, on that basis alone seems incorrect, particularly considering hovering consumes more power than slow forward flight given transition lift.

 

[priyank_sai]

The phantom 4 battery is 83wh. Hover from a full pack to 10% critical level with 175w consumption would give you 25 mins in the air. The 175w figure, on that basis alone seems incorrect, particularly considering hovering consumes more power than slow forward flight given transition lift.

Thank you for the help!
So by 83wh do you mean 83*3600 J = 298.8 KJ (of energy consumed in an hour by 4 rotors). Please correct me if wrong!

 

[With The Birds]

Thank you for the help!
So by 83wh do you mean 83*3600 J = 298.8 KJ (of energy consumed in an hour by 4 rotors). Please correct me if wrong!

There is a typo, I meant to say the P4 battery is rated at 81.3 watt/hours.

 

[priyank_sai]

There is a typo, I meant to say the P4 battery is rated at 81.3 watt/hours.

When you say 81.3 Wh does it mean battery charging or battery discharging value? How did you compute power supplied by battery during hover based on 81.3 Wh?
Any help will be appreciated. Thanks!

 

[With The Birds]

When you say 81.3 Wh does it mean battery charging or battery discharging value? How did you compute power supplied by battery during hover based on 81.3 Wh?
Any help will be appreciated. Thanks!

I’m not trying to determine power consumed in hover absolutely. I’m telling you that the 175w figure you have offered as the likely hover consummation is almost certainly less than actual. The battery watt hour rating is the wattage it can deliver into a load for one hour. It is simply Ah times nominal voltage. Actual capacity is almost always less so wh is optimistic it does provide for a useful comparison between packs though.

What exactly are you hoping to determine?

 

[priyank_sai]

I am using Optimal Control Theory to determine power required by the DJI Phantom while flying at 400 ft. However, I found a link to cross-check my results:
long range drone DJI Phantom 3 professional
The values of Power consumed by the vehicle i.e. DJI Phantom are between 130 W and 400 W.

The thing which is confusing me the most is if the battery watt-hour is 81.3 wh (as you explained above - it the wattage (in this case 81.3 W) that battery can deliver for an hour to the load) then how can it deliver 130 - 400 watt for the DJI Phantom to cruise which is higher than 81.3 W?

Hence my simple query is can the battery deliver between 130 W to 400 W instantaneous power for 10 minutes at least?

 

[With The Birds]

I am using Optimal Control Theory to determine power required by the DJI Phantom while flying at 400 ft. However, I found a link to cross-check my results:
long range drone DJI Phantom 3 professional
The values of Power consumed by the vehicle i.e. DJI Phantom are between 130 W and 400 W.

The thing which is confusing me the most is if the battery watt-hour is 81.3 wh (as you explained above - it the wattage (in this case 81.3 W) that battery can deliver for an hour to the load) then how can it deliver 130 - 400 watt for the DJI Phantom to cruise which is higher than 81.3 W?

Hence my simple query is can the battery deliver between 130 W to 400 W instantaneous power for 10 minutes at least?

Simple. 80W for an hour is 400W for 12 minutes.

 

[priyank_sai]

Simple. 80W for an hour is 400W for 12 minutes.

Cool so it can go beyond 81.3 W it's just that the battery will die soon because of State of Charge/Voltage will drop at faster rate.

Thank you again!

 

[Erised]

Many pilot have tested and some even did all the math and power consumption to maximum total distance attainable is cruising at 30mph +- or 13 ms. At this rate I can bring my battery down to 20% (this is my landing target) and never get a battery over current. My top recorded total distance is 44,222 feet in about 20 minutes and landing at 20%. (good conditions and I am sure I will get more distance when the weather cools a bit and have excellent conditions)

 

[With The Birds]

Cool so it can go beyond 81.3 W it's just that the battery will die soon because of State of Charge/Voltage will drop at faster rate.

Thank you again!

yes.

Max distance on a given charge is well known, max time aloft may have been explored and reported. I don’t know what it might be however intuitively from flying I suspect is is closer to hover than velocity for max distance.