GeirViking
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Norway
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DJI Diana Posted at 10-12 14:11
Hi GeirViking. Thank you for reaching DJI Forum. Please be advised that if a crash or collision incident occurs, we recommend sending the unit in for a proper diagnosis. Rest assured that as long as the unit is within the service guarantee period, we can forward an investigation and data analysis can be applied to determine its cause. We'll send you an offer depending on the results and it is also to ensure future flight performance. Please find this link https://dji.com/support?site=brandsite&from=nav helpful in contacting our Product Support team for further assistance on the request. Should you need to contact us for any reason, please know that we are always here to help. Thank you.
Thanks for your reply. But it's not good enough. I've searched a lot of similar threads on the forum, but never have I seen any detailed answers. Just "send it in". I'm not expecting a definite cause of the incident, but some possible causes would be nice.
I've extracted the flight data, and to me, it seems like cell 2 had insufficient current to power the motors. It was about 4,7 m/s winds that day, but gusts might have been higher. Voltage data shows that cell 2 voltage fluctuated quite a lot compared to cell 1. The deviation between cells was upwards of 0,056 volts. Voltage continued to drop rapidly during the flight, cell 2 more than cell 1. The max altitude was 107 meters, so there might have been some stronger wind gusts at that height.
Just before it fell to the ground, the voltage of the battery pack dropped by 0,18 volts for a second (cell 1: 3,48v and cell 2: 3,43v). Shortly thereafter, the drone reported another error code. A few seconds later, another voltage drop and another error code, until it reported "motor stuck", and it fell to the ground.
To me, it seems like the battery was faulty and couldn't deliver enough current when the cell 2 voltage dropped below 3,43 volts.
Some inputs on this theory?
And a tip to you at DJI, don't just tell people to send it in. Try to help people to understand what could have happened. |
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