Low voltage emergency landing

[Darrell1277]

Twice now I've had my mini 4k give the message "low voltage, emergency landing". Then it landed. I was able to retrieve it both times and it landed.safely. The battery was still almost fully charged. Any insights in to what could cause this?

 

[AeroJ]

1. How cold a day was it ?
2. How old are those battery packs / how many cycles on them ?

Most insights to what caused this should be available in the flight logs and on the battery status page within DJI Fly app. We need to know what the cell voltage levels were doing, before, at the time of the flight and now.

 

[Darrell1277]

Here is a screen shot of the flight log where it landed. Notice it's still showing 87% while emergency landing.

 

[AeroJ]

Unfortunately the screenshot doesn't show us voltage levels, but it does, as you say show you back at 87%.
But it also shows that at the time of the screenshot you were slowly descending and not moving very fast, so whatever sag had potentially caused the low voltage error had passed, and the battery had bounced back up to nominal levels. That's why we need the actual logs to see what that was doing at the time of the error message, and just before it.

I do notice you were in Sport Mode, which would have put the most demand on the packs when you did sharp ascends and / or fast forward movement, or if the craft has to fight a lot of turbulent wind...

 

[Felix le Chat]

Li-Ion batteries can't handle heavy draw for protracted periods... you will get low battery warnings and low battery reactions if you push a Li-Ion battery hard (sport mode).

Lithium-ion Polymer (Li-Po) batteries will handle this kind of treatment... that's the Li-Po's party piece....

...ten seconds to the inevitable argument over the difference between Li-Ion and Li-Po...

 

[Darrell1277]

Li-Ion batteries can't handle heavy draw for protracted periods... you will get low battery warnings and low battery reactions if you push a Li-Ion battery hard (sport mode).

Lithium-ion Polymer (Li-Po) batteries will handle this kind of treatment... that's the Li-Po's party piece....

...ten seconds to the inevitable argument over the difference between Li-Ion and Li-Po...

Thanks, brand new to the sport. Didn't even know there were battery choices. I'll probably stick to cinematic or normal with other 2 batteries and see what happens for awhile.

 

[Felix le Chat]

Thanks, brand new to the sport. Didn't even know there were battery choices. I'll probably stick to cinematic or normal with other 2 batteries and see what happens for awhile.

You're welcome. You end up finding the limitations of DJI drone tech with personal experience. With the early firmware: I've had a similar experience with my mini 3 pro.

DJI have addressed the 'excessive battery draw' problem by tweaking firmware in their newer mini drones, so it has become more unusual to see reports of it.

There aren't battery choices per-se... The newer DJI drones all use Li-Ion batteries, the older and bigger drones use the Li-Po's. The problem you documented is not unusual with the original mini and mini 2 (technically, you're 'mini 4K' would be a gen #1 mini SE).

If you keep it out of sport mode and don't try to push it to perform like a wasp on cocaine: you shouldn't see a repeat of the problem... the mini's aren't FPV quarry racers: like all DJI products (except for the FPV: the Avata etc.) they're very sophisticated miniature digital cameras that just happen to be able to fly.

 

[Darrell1277]

That's what I plan on doing. It's just strange that DJI would give you an option that's not usable. I went in a straight line. The whole flight was 3 minutes including the landing. I wasn't "quarry racing"

 

[Felix le Chat]

That's what I plan on doing. It's just strange that DJI would give you an option that's not usable. I went in a straight line. The whole flight was 3 minutes including the landing. I wasn't "quarry racing"

'quarry racing' isn't a derogatory term, it just means flying hard and fast... something that draws a massive amount of energy out of a storage unit that isn't designed to cope with it for more than ten seconds at a time.

And as you'll find out, DJI is a bugger for advertising options that are nowhere near as efficient as they make out they are... They're good - but nowhere near as good as the marketing hype would have you believe. The marketing teams will have you believe that DJI drones are all but uncrashable because of APAS and Obstacle Avoidance. An awful lot of posts on this forum will scotch that myth