Nearly lost my Spark due to running out of "juice"

[Vader01]

Here is a flight from today where I almost lost my Spark in Old Tampa Bay where I nearly ran out of power and had to keep it in the air long enough to bring it back because it kept wanting to auto land in Old Tampa Bay....yikes I was **** lucky.

 

[McCloudSpark]

With each flight we learn a little. Glad you could save it!

 

[nilanjan118]

It seems DJI has coded their software in such a way that it shows 0% even when there is quite a bit of gas left in the tank. I am not suggesting that people should take it for granted but if you see the video below, you will find that the pilot was able to cover quite a distance even after the app showed 0% battery.

 

[webvan]

Close !
Airdata shows 0 cycles, is it a brand new battery ?

 

[Vader01]

Close !
Airdata shows 0 cycles, is it a brand new battery ?

No it's not. It has been charged 40 times.

 

[pashokk]

So what's happened on the way back home? Why speed was dramatically slower?

 

[Vader01]

I took it out of sport mode to conserve the battery when it got to 10% plus the battery had gotten so low it wanted to do an emergency auto landing which it is programmed to do and I was still over a 1000 ft away over water. At one point it got to a foot above the water and I believe it was still over 800 feet away when that happened.

 

[nilanjan118]

I took it out of sport mode to conserve the battery when it got to 10% plus the battery had gotten so low it wanted to do an emergency auto landing which it is programmed to do and I was still over a 1000 ft away over water. At one point it got to a foot above the water and I believe it was still over 800 feet away when that happened.

Don't think you did the smart thing there. In sports mode you get the best balance between distance travelled and power consumed. You should always flip to Sports mode when you are running out of battery and have plenty of distance to cover to reach home.

 

[Vader01]

Thank you for the advice, I will do that if this ever happens to me again which I hope it doesn't.

 

[webvan]

It's been argued that the optimized speed was the RTH speed (around 35kph?) so that will require sports mode but not at full throttle.

 

[nilanjan118]

It's been argued that the optimized speed was the RTH speed (around 35kph?) so that will require sports mode but not at full throttle.

That's correct. But even if you go full throttle in Sports mode, you stand a much better chance than P-mode. If we talk only in terms of flight time also, you can easily see with a couple of test flights that hovering in place consumes the maximum battery and zipping around in Sports mode consumes the least.

 

[Spark 317]

That's correct. But even if you go full throttle in Sports mode, you stand a much better chance than P-mode. If we talk only in terms of flight time also, you can easily see with a couple of test flights that hovering in place consumes the maximum battery and zipping around in Sports mode consumes the least.

And if anything else, you have the speed, altitude and momentum, along with a slight arc, to push the Spark that much closer to you when it does fail and gravity takes over.

It could be the difference between a water landing or a shore landing if super lucky.

 

[sparkflyJEF]

With each flight we learn a little. Glad you could save it!

charge to experience

 

[ajkm]

Did you check the wind speed and direction at different altitudes before you took off?

 

[Vader01]

Did you check the wind speed and direction at different altitudes before you took off?

The surface wind was between 7-10 mph. I believe the winds were from the SW that day.

 

[ajkm]

And the wind direction was...?

Also don't forget about land and sea breezes.

 

[ajkm]

And of course there's a considerable difference between wind conditions at ground level and at 261ft, particularly over water.

 

[ajkm]

The surface wind was between 7-10 mph. I believe the winds were from the SW that day.

From the picture it's not possible to identify the course outbound or inbound but it's crucial to use something like UAV Forecast to have accurate information at 33, 100, 250, and 500ft before you fly.

Flying back against a headwind (also need to know the headwind component of a crosswind) uses some 30%+ more battery power. Trust the yellow indicator on the app and turn back as soon as you reach it.

The other thing to consider is that running down a LiPo battery to 1% is extremely bad for it.

 

[ajkm]

I would also recommend maintaining vlos flight at all times; these scenarios typical happen for pilots using goggles or relying on FPV through their phone/tablet and thereby losing accurate situational awareness.

 

[Vader01]

That flight was the first time I have had my Spark do an auto return with the battery at 39%. Think my biggest mistake was an hour or so before flying I had left my Spark in the car while I ate lunch and the temperature in the afternoon at reached into the low 90's. I should have brought my Spark inside with me and not left it in the car. I'm not one to run my batteries down to less then 1% since I know that shortens the life of the batteries.