critical low battery landing...landed with 85% battery

[hiflyer201]

Yesterday a couple of minutes after takeoff with a full battery I got an announcement the I had a critically low battery and the drone was landing. I found a good spot below me and landed and hopped in the car and and picked up my drone.(whew) ..the lights were still flashing, but in my haste I turned off the battery and really didn't notice how many lights were blinking. Today on Airdata I see that I had 83% battery when the drone landed. It looks like I had a huge glitch in the battery voltage/amps..
Why did this happen?

 

[Fly Dawg]

Why did this happen?

No way to know without the logs. Upload your .txt device log to the link below to start with and share a link back here. OR share your airdata link here. ( Be sure and make it fully sharable ). We can take a look.

DJI Flight Log Viewer | Phantom Help

 

[Chris @ TDT]

I'd drain that battery down to 8%, and then charge it fully again. It sounds like it was probably an unexpected voltage drop or something, that could be rectified by recalibrating the battery.

 

[Fly Dawg]

I'd drain that battery down to 8%, and then charge it fully again.

Not a great thing to do in this instance. I suspect that there is a cell (or two) that are far out of balance. Normally charging to 100% will balance the cells. Plus the OP never stated which aircraft.

 

[hiflyer201]

No way to know without the logs. Upload your .txt device log to the link below to start with and share a link back here. OR share your airdata link here. ( Be sure and make it fully sharable ). We can take a look.

DJI Flight Log Viewer | Phantom Help

 

[hiflyer201]

Thanks, Fly Dawg and Chris..
this has probably been asked again and again..how do you attach files from Airdata? CVS or KLM??

 

[Chris @ TDT]

Not a great thing to do in this instance. I suspect that there is a cell (or two) that are far out of balance. Normally charging to 100% will balance the cells. Plus the OP never stated which aircraft.

Why would you avoid it in this instance? I've had great success with poorly performing batteries coming back into balance after a low drain and then fully back to 100%.

 

[Fly Dawg]

@Hi-Flyer ....As I suspected you had two cells far out of balance. These two dropped below the threshhold and started the forced landing sequence. The above suggested advice is good, however you should not do this with new batteries. How many flights has this battery had?

 

[hiflyer201]

Gosh..thanks for your help. According to airdata it's been charged 94 times. I've got three batteries for this Mavic Air and one has a very slight bulge this particular battery is flat as a board.

 

[Fly Dawg]

I've got three batteries for this Mavic Air and one has a very slight bulge this particular battery is flat as a board.

I would discard the bulging battery. For the others try the 8-10% discharge cycle. That may re-balance them.

 

[hiflyer201]

Thank's Pal.. ...Thats the first time I've ever seen that critical Low Battery ..landing!...Yikes...I returned it to earth in a rapid fashion and jumped in my car and hauled xxx .I was sure I was going to see someone sprinting down the street with my drone.. I was pretty surprised when I looked on airdata this morning and saw how much battery I had left.

 

[Delmarksman]

You may already have your answer, but I want to ask, what was the battery temperature?
We were having similar battery problems flying at work in cold temperatures the other day.

 

[hiflyer201]

You may already have your answer, but I want to ask, what was the battery temperature?
We were having similar battery problems flying at work in cold temperatures the other day.

I looked back at AirData. They listed the min at 73 and 104 for the Max...