P4P Battery question?

KevMo Photog · Apr 12, 2017

Does anyone know what happens if a Phantom is allowed to run down battery until it goes into auto land at say 200ft in the air? Does it know how much battery at that altitude it will need to descend all the way down softly? Or would it just fall out of sky after so long. What if bird was say 400ft or even higher? Just curious to know this one.

msinger · Apr 12, 2017

KevMo Photog said:
Does it know how much battery at that altitude it will need to descend all the way down softly?

It doesn't know for sure since the Phantom has no idea where the ground is located when it's high up in the air. If the elevation of the ground at the Phantom's current location is fairly close to the elevation at the takeoff location, then it should make it to the ground in time.

alokbhargava · Apr 12, 2017

If the wind is not very strong, phantom can definitely land safely with 10% remaining battery charge assuming battery is in good shape. I usually raise the critical battery level to 15% for old batteries just to be safe.

KevMo Photog · Apr 12, 2017

msinger said:
It doesn't know for sure since the Phantom has no idea where the ground is located when it's high up in the air. If the elevation of the ground at the Phantom's current location is fairly close to the elevation at the takeoff location, then it should make it to the ground in time.

Ok, so your saying that as long as it close to takeoff altitude it should be good. So if was not, and it was say 400ft above takeoff then your screwed right. Cause it's gonna take longer to get down from that height than 10% will give you?

KevMo Photog · Apr 12, 2017

alokbhargava said:
If the wind is not very strong, phantom can definitely land safely with 10% remaining battery charge assuming battery is in good shape. I usually raise the critical battery level to 15% for old batteries just to be safe.

I'm talking about a case if the bird was right over your head at 400ft and the battery goes to 10%. Will it land softly or will it fall out of sky?

Bckmstr · Apr 12, 2017

it will land softly, as bird will go into auto land depending at what % you set it at

KevMo Photog · Apr 12, 2017

Bckmstr said:
it will land softly, as bird will go into auto land depending at what % you set it at

Thx for reply man. So lets say it's at 10% at 400ft. Will it make it all the way down soft?

Bckmstr · Apr 12, 2017

KevMo Photog said:
Thx for reply man. So lets say it's at 10% at 400ft. Will it make it all the way down soft?

yep , my p4 did

KevMo Photog · Apr 12, 2017

Bckmstr said:
yep , my p4 did

Wow! Thats awesome! Thanks a lot for that answer!

Meta4 · Apr 12, 2017

KevMo Photog said:
Thx for reply man. So lets say it's at 10% at 400ft. Will it make it all the way down soft?

If you want to keep the Phantom, aim to be on the ground by 20%.
The day you are cutting things too close is the day you can count on complications.

KevMo Photog · Apr 12, 2017

Meta4 said:
If you want to keep the Phantom, aim to be on the ground by 20%.
The day you are cutting things too close is the day you can count on complications.

Totally hear ya Meta4! I've only been below 20% maybe once or twice. I'm always back in close by 25 or so. But I was just totally curious what happens in a weird case and the bird was a total disconnect and was way up like 400ft. Love to know the what if's. LOL

msinger · Apr 13, 2017

KevMo Photog said:
Ok, so your saying that as long as it close to takeoff altitude it should be good. So if was not, and it was say 400ft above takeoff then your screwed right. Cause it's gonna take longer to get down from that height than 10% will give you?

I'm assuming DJI has added some kind of buffer to account for possible altitude differences. You're going to be screwed at some point though. Like anything when it comes to flying Phantoms, you're always going to be better off by not fully relying on its automated systems.