Lesson learned from crash by RTH because flying with a low battery

[Ricardo Silva]

I just have a question the RTH can enter after the p3 pass the H point of low battery.
Because mine after pass 22 seconds of the H point kick the RTH and have no battery to do the RTH ?
Only have 01:32 seconds of battery left

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[roymoon]

Why bash DJI when it was totally your fault ?
You should be on the ground by the time you get that low.
I'm usually on the ground before I get the low battery warning never mind the critical warning.

 

[RodPad]

Why bash DJI when it was totally your fault ?
You should be on the ground by the time you get that low.
I'm usually on the ground before I get the low battery warning never mind the critical warning.

"Why bash DJI when it was totally your fault ?"
Who is bashing? I had to go back and look.
Are you referring to @bearmikie, If so I think he was mad because it happened, and what it cost to fix it.
Anyways just wondering

Rod

 

[jeganx]

Same here. I had to look back. who is bashing DJI?

 

[RodPad]

Same here. I had to look back. who is bashing DJI?

 

[gryphon1911 (Andrew L)]

Well same thing here. I had my P3A 25 feet from me. The low battery kicked in. I tried to stop it but no good. It went up about 15 feet right in to the tree. Then right down to the street. Estimated repair bill $480. Really Im pissed. I could do nothing to stop it.. But of course DJI would do nothing about it and I couldn't get their care package to get it fixed.

They need a kill switch for the RTH. Next time I bypass DJI and go to say Chroma or Autel.

I think this statement is what might be bringing the "DJI bashing" statement. Only conjecture on my part, though.

 

[Ricardo Silva]

Hi everyone,
First sorry to took so long to upload

I got a new P3A, this one i tested and it's ok

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[solentlife]

Its the dilemma isn't it ..... you want it to fly home when at rsnge , but don't want it to fly into anything.

One day flying in the trees, another day flying over the trees. Another open fields, another wooded or residential area .....

Each has its own parameters. Even a P4 will not avoid everything.

What to do ? Modify settings every time you fly ? What about the critical low battery and what model does then ?

I know when RTH has been operating - I have been able to override with sticks or switch it off - but I have always had plenty of battery life left and RTH was triggered by me, not auto.

Interesting - what to do.

Nigel

 

[solentlife]

Page 11 - 12 of the standard manual indicstes that flight control is still available to us even when critical battery kicks in. OK with critical battery you cannot RTH but you can affect where it lands. Second that critical battery according to manual says descent is triggered immediately and makes no mention of climbing to RTH altitude.

Only Smart and manually triggered RTH climb to preset altitude. That can be arrested by use of sticks if necessary.

Of course the trick is to stay calm and remember the above !! But we all know what happens when it comes to the crunch !

Nigel

 

[Ricardo Silva]

Yes you'r right.

In my case, i canceled the message of low bat (smart rth) and after pass the H point my P3A does a low bat rth and i push the stickers down and he don't respond to the comands

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[Ricardo Silva]

I don't know what appened but it's strange becouse i put my new one in open field in same conditions and he makes everything perfect.



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[solentlife]

As I understand it - critical battery state - you cannot make the bird stop descending, all you can do is offset its point of landing.

OK - I think we have to look at a matter of lipo use and how esc's operate with them. In normal models once a lipo huts lvc - the ESC shuts of power to motors, but controls are still there. A fixed wing model will then be left to be glided to ground.

With a multi-rotor that is certain death. So I think the system is set yo give reducing 'soft cutoff' so motors continue to run but at a level that model descends.
Control of model is reduced to that which can only slightly alter motors rpm and therefore descent path. If you had more power available - that would be death to the model.

Critical level on a lipo is generally considered to be below 3v per cell - levels that are damaging to lipo's. Levels also that you cannot expect on any ESC controlled model to have power to fly.

I post this as food for thought - based on using esc's on many different models and that there has to be ESC within our P3's as part of our flight control system.

I think like other models - we do well to fly within battery reasonable levels and avoid wherever possible situations of pushing the lower limits of operation. I know I do not wish to hit critical on my P3 battery's - not when they cost 3... 4x that of a normal same size lipo !

Nigel

 

[Multicoptertec]

Its the dilemma isn't it ..... you want it to fly home when at rsnge , but don't want it to fly into anything.

One day flying in the trees, another day flying over the trees. Another open fields, another wooded or residential area .....

Each has its own parameters. Even a P4 will not avoid everything.

What to do ? Modify settings every time you fly ? What about the critical low battery and what model does then ?

I know when RTH has been operating - I have been able to override with sticks or switch it off - but I have always had plenty of battery life left and RTH was triggered by me, not auto.

Interesting - what to do.

Nigel

It's called a flight plan. These aircraft are sophisticated, but they don't perform magic tricks.


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[solentlife]

Fine but your flight plan is of no use when you hit critical battery level.

It can happen. Let's say you create a flight plan to fly a route and video ..... at ground level wind is fine, but once you ascend and leave your take-off area, the model meets upper air turbulence / different conditions. Your battery margin can easily be depleted without your knowing except if you are diligent enough to watch the top battery line of your screen. So the model is getting depleted on battery .... RTH kicks in or you instigate it. Model now fighting to get home .... etc. etc. etc.

S*** happens as they say.

Nigel

 

[Multicoptertec]

Battery levels and weather are part of the flight plan.


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