How far to let battery go down before bringing it in?

[Chirp]

For example: You are doing a job where you need to get the most out of your three batteries or
you may not be able to finish. I am photographing a location from the different cardinal points around the compass to get photos of a central site at different altitudes and I want to finish in one trip because it's far away and I don't want to buy another battery yet.

Right now I have first warning at 30% and final at 10% and I start bringing it in soon after the 30% alarm goes off. For the job I am doing now, 1,000 feet is about the maximum distance from drone to home.

In the interest of getting maximum usage of the batteries would it be OK to let the quad decide
when to bring it in? I have read that it will return when it has just enough battery life to do so.

It seems that would be the way to stretch the battery time to its fullest but I don't know if it's asking
for trouble.

Thanks!!

 

[Timster1973]

I don’t know I guess 10% would be ok to give it time to fly it back to you. I’ve only had mine 2 weeks and it started at 30% like you and the noise is enough to make you feel that it’s time to bring it back and change the battery!

I let it run to 18% and changed it in the end. Better safe than sorry!!

 

[Chirp]

I don’t know I guess 10% would be ok to give it time to fly it back to you. I’ve only had mine 2 weeks and it started at 30% like you and the noise is enough to make you feel that it’s time to bring it back and change the battery!

I let it run to 18% and changed it in the end. Better safe than sorry!!

Thanks... Welcome...

 

[Timster1973]

Thanks... Welcome...

Thanks man, the novelty of the thing is still there. I’ve only flown 6 times and it’s so amazing!

 

[Blacksails]

You have to remember that the discharge curve of LiPo or LiHV batteries drops off sharply towards the end. That 10% will probably disappear waaaaaay faster than say 50% to 40%. Don't get caught out.

 

[Chirp]

You have to remember that the discharge curve of LiPo or LiHV batteries drops off sharply towards the end. That 10% will probably disappear waaaaaay faster than say 50% to 40%. Don't get caught out.

Got it, thanks...

 

[Chirp]

I may have been able to find useful information to tell when to start reeling it in.



This is from the online manual for DJI GO 4. DJI GO 4 Manual: The Pilot’s Handbook
I will check it out on a local test before I fly out very far. The link to the manual is above if anyone needs it...
If this automatically adjusts for battery loss due to cold temperature, it may prove to be very useful.

 

[BubbaDan]

I have a suggestion for you. Try Litchi. You can preprogram your flight, camera angles and everything. I found that for longer jobs like you’re doing, litchi works better because there are no miscalculations or the like in the flight. In testing, a job that I couldn’t do by hand, litchi brought the Mavic home with 12% battery left. I tried that course 5 times and had to quit before finishing or land and fetch. For $22 it was a real deal.

 

[BigAl07]

10% is when the aircraft hits Critically Low Voltage which means it's going to Land NOW. You could lower your first Low Battery Warning level a little below 30% but 10% CRITICAL LOW is not the one I would play with.

Also the aircraft Fight Controller using algorithms to try and determine (aka Guesstimate) how much power to get home but it has no way to factor in climbing, obstacle avoidance, WIND etc etc. Allowing the FC to make this decision for you could be running yourself down the rabbit hole.

Lastly, like @Blacksails mention the discharge characteristics for LiPo are not exactly linear and it can get "interesting" at lower percentages.

Think about it like this... buying a single extra battery is going to cost you <$100 but pushing your battery could cost you to "Puff" your battery or it could also cost you your UAS which could cause an "incident" if it autolands in a less than ideal location (ie roadway??). Is this really worth it? If you're going to be in business then you need to step up your game and get the goods to operate in a professional and SAFE manner as opposed to "pushing" the envelope.

 

[Blacksails]

10% is when the aircraft hits Critically Low Voltage which means it's going to Land NOW. You could lower your first Low Battery Warning level a little below 30% but 10% CRITICAL LOW is not the one I would play with.

Also the aircraft Fight Controller using algorithms to try and determine (aka Guesstimate) how much power to get home but it has no way to factor in climbing, obstacle avoidance, WIND etc etc. Allowing the FC to make this decision for you could be running yourself down the rabbit hole.

Lastly, like @Blacksails mention the discharge characteristics for LiPo are not exactly linear and it can get "interesting" at lower percentages.

Think about it like this... buying a single extra battery is going to cost you <$100 but pushing your battery could cost you to "Puff" your battery or it could also cost you your UAS which could cause an "incident" if it autolands in a less than ideal location (ie roadway??). Is this really worth it? If you're going to be in business then you need to step up your game and get the goods to operate in a professional and SAFE manner as opposed to "pushing" the envelope.

Good advice. This man [emoji108]. Don't risk it

 

[Mossiback]

You did not mention the terrain you will be flying over. If it is an open area where you can retrieve after an emergency landing then there is not much to worry about. If not and you are flying manually, make sure you fly your upwind leg first so you are not fighting the wind on the way back.

If you want repeatable results or you would like to plan ahead of time, use Litchi. Be warned though to observe the flight closely and be ready to pause it. There could be an obstruction that Litchi will allow you to fly into if the sensors are not pointed at it in flight.