RTH question

[wxperson]

I was about 40' away from my home point at about 5' in altitude when the RTH procedure was automatically initiated with my battery at 17%.

Why would the Mavic want to do a RTH when I was only 40' away from "home".

I did cancel it and flew a bit more before landing.

 

[msinger]

Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like other people to review and comment on your flight log, then please post a link back here after you upload it.

 

[wxperson]

Hopefully I did this correctly. I don't see any message about RTH... which I had to cancel.

DJI Flight Log Viewer - PhantomHelp.com

 

[msinger]

Your Mavic auto initiated RTH at 19m 25.4s due to a low battery. A prompt will pop up in DJI GO to allow you to cancel that RTH. If you ignore that prompt, RTH will be auto initiated after 10 seconds.

 

[wxperson]

ok... when I downloaded the CSV file... I see the RTH. I was 60' away from home at just a few feet up and battery was 18%. Is there any indication of why it wanted to RTH with 18% left?

 

[wxperson]

Your Mavic auto initiated RTH at 19m 25.4s due to a low battery. A prompt will pop up in DJI GO to allow you to cancel that RTH. If you ignore that prompt, RTH will be auto initiated after 10 seconds.

Is the RTH aware of my being 60 feet from home at just a few feet altitude? i.e. does it factor in distance?

 

[msinger]

It does factor in distance in order to determine how much time it needs to make it back to the home point when the battery is low.

 

[wxperson]

It does factor in distance in order to determine how much time it needs to make it back to the home point when the battery is low.

Thanks... just still wondering why it would choose 18% to RTH when home was 60 feet away... but thanks for the info.

 

[okw]

I was about 40' away from my home point at about 5' in altitude when the RTH procedure was automatically initiated with my battery at 17%.

Why would the Mavic want to do a RTH when I was only 40' away from "home".

I did cancel it and flew a bit more before landing.

Let's say you were standing on a dock and flying over a river or lake. And you were 40' from shore when the battery got low enough to trigger the automatic RTH. If it just landed, instead of returning to home, you'd then be swimming to try to find it. That's just one reason it returns to home. The same reasoning could be used for standing at the edge of a cliff and flying over a canyon. Well, except for the "swimming" part.

However, the manual states that if RTH is triggered within 5m of the home point, the Mavic will simply land where it is. So make sure that you don't trigger it 4.5m over the edge of that cliff.

 

[okw]

Thanks... just still wondering why it would choose 18% to RTH when home was 60 feet away... but thanks for the info.

I believe the minimum battery level for RTH is set in the DJI Go 4 app.

 

[wxperson]

Let's say you were standing on a dock and flying over a river or lake. And you were 40' from shore when the battery got low enough to trigger the automatic RTH. If it just landed, instead of returning to home, you'd then be swimming to try to find it. That's just one reason it returns to home. The same reasoning could be used for standing at the edge of a cliff and flying over a canyon. Well, except for the "swimming" part.

However, the manual states that if RTH is triggered within 5m of the home point, the Mavic will simply land where it is. So make sure that you don't trigger it 4.5m over the edge of that cliff.

Thanks... but why at 17% when 60' from home. I would understand it better if it determined a RTH at a lower value.

 

[okw]

I mentioned above that I thought that there was a setting for the absolute minimum battery level for RTH. But I just powered up DJI Go and can't find it. Only the Critical level setting where Mavic will start to land, and the initial Low Battery Warning level.

So the 17% level does indeed seem odd.

 

[tcope]

Thanks... but why at 17% when 60' from home. I would understand it better if it determined a RTH at a lower value.

Keep in mind that the 17% is a guess by the software. It reads the voltage in the lowest cell to get this information. It's not known how the Mavic determines the battery needed to return but it might not be that "guess" of 17%.

Regardless, keep in mind that a good rule of thumb is to be back near the landing area at 30% and landing around 20%. Pushing it further then that and you are getting close to trouble. It's in that low battery area that many people have issues.

 

[msinger]

I mentioned above that I thought that there was a setting for the absolute minimum battery level for RTH. But I just powered up DJI Go and can't find it.

There is no such setting.

 

[Mattw996]

Lost sight of my drone after clouds rolled over a cliff I was photographing, would no longer have a drone if it wasn't for RTH, great feature.

I usually do it manually just to improve my pilot skills.

 

[SwissJim]

Why the question is even asked is confusing to me. Be happy that the drone and software were cautious enough to come home. Switch batteries and fly with an intact drone. Clear skies to you and all.

 

[butterflyslicer]

It does factor in distance in order to determine how much time it needs to make it back to the home point when the battery is low.

True. I was 5.5kms from home and return to home kicked in at 60% battery power. I cancelled for around one minute and made it home with 12% left.

 

[mlash]

Thanks... just still wondering why it would choose 18% to RTH when home was 60 feet away... but thanks for the info.

Because the "smart battery" determined at 18% and the distance you were from the controller was only enough to get you home and landed before you hit critical battery! Keep in mind that "smart battery" is very conservative and will activate with way more than enough time to get you home safely.

If you were let's say 200 ft away it might have kicked in at 22% (just for an example)

 

[Porto]

Thanks... but why at 17% when 60' from home. I would understand it better if it determined a RTH at a lower value.

Because it calculates that you need to RTH and land at that value before the first stage of auto land will kick in. First stage of auto land will kick in at 15% battery level. You can slide and cancel the auto land. The second stage of auto land will occur at 10%. You can't cancel this one. You can still fight it by pushing the left stick up, but at a certain point the AC will land anyway.

Not good for the battery to be depleted until below 10% too often though.

 

[msinger]

First stage of auto land will kick in at 15% battery level. You can slide and cancel the auto land. The second stage of auto land will occur at 10%. You can't cancel this one. You can still fight it by pushing the left stick up, but at a certain point the AC will land anyway.

Are you referring to RTH or auto land?

The Mavic will only auto land when the battery reaches the critical low level. That does not occur at a specific battery level and there is no way to cancel it.