Phantom 2 Vision + Losing power / altitued?????

[alopez]

Today I flew the drone. I was at 40 meters high when notice a fast drop in altitude that I couldnt control. Luckly It was not that bad of a landing. But still I cant explain what happened, the batery was that 30% when this happened, I couldnt gain altituted and the drone keptlosing altituted, Any advice or opinions on the matter?

Thanks

 

[J.James]

Sounds like VRS (Vortex Ring State) which can happen if descending straight down to fast. Then it can become un controllable.

Here is a good thread on how to avoide it or to recover from it if it happens.

viewtopic.php?f=4&t=17468&hilit=VRS+recovery+plan

 

[alopez]

Re: Phantom 2 Vision + Losing power / altitude?????

Ok ran another test today. And here are the results.

First fligth no mayor issues, olny having problems keep steady position. Baterry ran until 10%.

Second fligth hovering at 3 meters, with diferent battery, but around 35% to 30% drone kept losing altitude. Couldnt get it up even with the controller that full throttle. I grabed it and landed it. Once in the ground I took it off the ground for another short hover and the same problem once again. No mayor out of control problemsbut it seems it wont hold altitude. Could this be a battery issue? any advice ? Thanks

 

[J.James]

Your gains could do that if they are not right and also depending on what version of the soft ware you are using it could be trying to auto land if the battery is lower then what ever the default low battery setting is set to. If thats the case tho the tail lights will start blinking red.

But if its just a not holding position type thing they can get a bit bouncy if low to the ground from the prop wash.

 

[fastsmiles]

Check the limits on the battery in your DJI Pahantom 2 Vision Assistant program. Sounds like auto land is being initiated.

 

[Fyod]

Compare the battery voltages, not the percentages of those two batteries, as some have indicated that percentage is not a reliable value.
This is not a settings issue, otherwise it would do the same on both.
You are probably experiencing a battery with a bad cell, which seems common recently. Retailer should replace it.
Which FW version are you on?

I tested autoland today because I wanted to drain my battery, I was 3-5ft above ground just in case.
25% first warning (I set this)
15% second warning and autoland slowly begins, but throttle is still responisive and goes up pretty swiftly
13% hovering a foot up with full throttle, not enough power to go higher
11-12% barely above ground, no throttle response
10% landed, sticks barely move the motors in any direction

Unfortunately I don't remember the voltages, but iirc, 10% was about 10.6V.

 

[alopez]

Its has the latest firmware installed. Also whats the best way the diagnose the battery ?? Is there any way the check the battery the foresee this kinds of problems?

Thanks

 

[J.James]

easiest and best way is to have a fully charged battery and with it in the phantom plug in to the naza assistant software. Then go to the advanced tab then battery and look at the "currant capacity" which should be 5200mah or close to it. and the voltage at the very top under currant status should be about 12.5 or 12.6volts If the battery is at 100%

and also on the right hand side it will show the cell voltage for all 3 cells. All 3 should be about the same voltage. around 4.10 to 4.20 volts. If one or more cells are bad they will be off my atleast 1/2 a volt or more from the others. and also will still say its 100% charged but your "currant capacity" will be a lot less then 5200mah. If 1 cell is bad you will see the "currant capacity" be around 3400-3500mah or if even 2 cells crapped the bed then it will be even lower like about 1700mah or so.