Mavic 2 Pro Forced Landing

Went out tonight with friends to fly around some local lakes, all batteries charged yesterday. First flight was uneventful , up to 400ft and flying around the lakes came back and landed to change the battery.
2nd flight took off climbed up to around 240ft and started flying back towards the lakes. Few seconds Not enough Force/ESC error, battery then went from 95% to 0% , it then went into a forced landing, I was over large bushes at the time and I managed to input and fly straight and it landed safely in a field 500ft away. When I recovered it GO app was still showing 0%, however Airdata has it changing back to 92%
Prior to first flight it mentioned about the firmware updated, but as I was not on wi-fi , I did not update in the field.

I then flew with a 3rd battery no issues.

Any thoughts? Props are master airscrew, all checked all good.

Cheers

Only a couple of thoughts. The batteries also have to be updated because they are also mini computers. However looking at the warnings I see that cell 3 has a deviation from the others. It might only be .1% but if the parameters have been set low by DJI to give a warning and possible forced landing due to a possible battery issue mid flight then this is where the problem is. As an aside, we have a similar system on the railway called Remote condition monitoring which among other things,monitors the current drawn by points motors when they move the points to switch trains from track to track. If the current draw starts to deviate from a parameter set by someone sat in an office, it will send an alert to a mobile phone to the mobile maintenance team to respond to check things out. If the alert level is set too low by the person in charge of the computer, the maintenance crew can be chasing shadows. Obviously having an aircraft in the air getting a low voltage alert can have safety implications so I suspect this is what happened.

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Hi Brian, many thanks for that, I was thinking roughly the same, also thinking it may of been tied in also with the drone controller knowing I needed a firmware update and me not doing it, especially as the latest is around batteries.
My 3 batteries have all been upgraded and recharge, I will do some test flights so that I can get my confidence back, as this was a very close call and I was over a field, so it was able to land safely, another 40 seconds and I would have been over the centre of the lake.

Can I ask you Kev, have you just done the 21/4 DJI UPDATE? That was battery related.

Hi Mark, I had not updated at the time of the event, I updated all when I got back home.

I performed a test hover in the back garden after work, hovered for minutes and then landed, noticed the battery had unclipped on one side, due to swelling. So would guess the battery is shot.

Some info on the battery, it was no2 in my set of 3, all get stored in a hard case and get charged to 100% prior to each flight, it was bought brand new as part of a fly more pack in Feb 2019, it was manufactured on 02-Nov-2018, battery life 96% charged 38 times (least of my 3 batteries) recorded temperatures today Min 81.7 f Max 138.4 f
So as you can see not over worked, but obverse that is not safe to use again.

Raise a ticket with DJI, always worth a punt

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You normally get a warning if the battery isn’t clipped in correctly. I also have a swollen battery with same manufacture date and similar number of charges. I only use ithat battery for updates or transferring photos while sat on the kitchen table cos it’s too risky to fly with it.