Bad Batteries

[Ungava]

Great suggestion and I will do that today. I did notice on my carpet test that the V was about the same on the 1st & 3rd cells and lower on the 2nd. I cannot remember exactly the difference but I will make notes today at 10% intervals. FYI, it was -6C or about 20F when this occurred. Should not be a problem but it was the first time I flew at this temperature. The battery was a normal warm when I pulled it from the drone. I put in another battery and flew 200M back and forth on the country road I was parked on until the battery reached 5% and there were no issues. Makes me believe the issue is isolated to the battery. also FYI, this last test flight lasted 32m40s which is the longest flight I have had with a drone. Beat the P4PV2.0 which was 29m32s under warm ideal summer conditions. I will keep everyone informed. Thanks for the help. Les

OK. I downloaded the FW BIN onto a sd card and it booted up just fine. I recharged the questionable battery to 100%. I launched the EVO 2 PRO 3' off the carpet. I recorded the voltage on the 3 cells every 5%. Here are the results:

100% 4.344 4.314 4.325
99 % 4.326 4.298 4.309
95 % 4.112 4.200 4.169
90 % 4.067 3.977 4.028
85 % 4.025 3.933 3.998
80 % 3.986 3.886 3.936
75 % 3.943 3.842 3.892
70 % 3.905 3.797 3.852
65 % 3.866 3.762 3.812
60 % 3.832 3.723 3.777
55 % 3.799 3.693 3.746
50 % 3.769 3.666 3.721
45 % 3.741 3.643 3.692
40 % 3.718 3.625 3.673
35 % 3.697 3.609 3.657
30 % 3.678 3.589 3.642
25 % 3.665 3.554 3.621
20 % 3.653 3.457 3.586
17 % 3.643 3.313 3.559
16 % 3.638 3.228 3.546
15 % 3.632 3.140 3.529
14 % 3.627 3.077 3.511
13 % 3.626 2.990 3.490
12 % 3.623 2.929 3.472
11 % 3.617 2.850 3.344
10% auto land at 0% flight time 26m1s battery temp 57.6C

So the flight time was shorter. At 10% the battery showed 0% and I had to land. Landing was swift and firm. As previously posted, I contacted Autel last Thursday and I have not heard from them yet....
your thoughts folks .....

 

[moodman]

OK. I downloaded the FW BIN onto a sd card and it booted up just fine. I recharged the questionable battery to 100%. I launched the EVO 2 PRO 3' off the carpet. I recorded the voltage on the 3 cells every 5%. Here are the results:

100% 4.344 4.314 4.325
99 % 4.326 4.298 4.309
95 % 4.112 4.200 4.169
90 % 4.067 3.977 4.028
85 % 4.025 3.933 3.998
80 % 3.986 3.886 3.936
75 % 3.943 3.842 3.892
70 % 3.905 3.797 3.852
65 % 3.866 3.762 3.812
60 % 3.832 3.723 3.777
55 % 3.799 3.693 3.746
50 % 3.769 3.666 3.721
45 % 3.741 3.643 3.692
40 % 3.718 3.625 3.673
35 % 3.697 3.609 3.657
30 % 3.678 3.589 3.642
25 % 3.665 3.554 3.621
20 % 3.653 3.457 3.586
17 % 3.643 3.313 3.559
16 % 3.638 3.228 3.546
15 % 3.632 3.140 3.529
14 % 3.627 3.077 3.511
13 % 3.626 2.990 3.490
12 % 3.623 2.929 3.472
11 % 3.617 2.850 3.344
10% auto land at 0% flight time 26m1s battery temp 57.6C

So the flight time was shorter. At 10% the battery showed 0% and I had to land. Landing was swift and firm. As previously posted, I contacted Autel last Thursday and I have not heard from them yet....
your thoughts folks .....

Try taking those numbers into a spreadsheet and graph them over time. Graph each cell separately and see visually if they have the same graph curves. My hunch is that the middle one is the bad one.

 

[herein2021]

OK. I downloaded the FW BIN onto a sd card and it booted up just fine. I recharged the questionable battery to 100%. I launched the EVO 2 PRO 3' off the carpet. I recorded the voltage on the 3 cells every 5%. Here are the results:

100% 4.344 4.314 4.325
99 % 4.326 4.298 4.309
95 % 4.112 4.200 4.169
90 % 4.067 3.977 4.028
85 % 4.025 3.933 3.998
80 % 3.986 3.886 3.936
75 % 3.943 3.842 3.892
70 % 3.905 3.797 3.852
65 % 3.866 3.762 3.812
60 % 3.832 3.723 3.777
55 % 3.799 3.693 3.746
50 % 3.769 3.666 3.721
45 % 3.741 3.643 3.692
40 % 3.718 3.625 3.673
35 % 3.697 3.609 3.657
30 % 3.678 3.589 3.642
25 % 3.665 3.554 3.621
20 % 3.653 3.457 3.586
17 % 3.643 3.313 3.559
16 % 3.638 3.228 3.546
15 % 3.632 3.140 3.529
14 % 3.627 3.077 3.511
13 % 3.626 2.990 3.490
12 % 3.623 2.929 3.472
11 % 3.617 2.850 3.344
10% auto land at 0% flight time 26m1s battery temp 57.6C

So the flight time was shorter. At 10% the battery showed 0% and I had to land. Landing was swift and firm. As previously posted, I contacted Autel last Thursday and I have not heard from them yet....
your thoughts folks .....

Just my opinion....but I really think you are wasting a lot of time on something that shouldn't be your problem...its an Autel problem and the battery is within warranty so what I would do is take it out of the rotation, never use it again and hound Autel for warranty support. I would not risk a $2000 drone over a $200 battery not to mention if the drone falls out of the sky and injures someone one on the ground or damages some property you could be looking at a lot more than that.

Additionally, LiPo batteries are very combustible so a problem like that could end in a battery fire or worse. I don't take any chances with LiPos; so I would follow whatever guidance Autel gave me to the letter and keep all communication in writing between yourself and Autel in case that battery ends up causing real damage or your loss of the drone.

 

[GeoDrone SRL]

OK. I downloaded the FW BIN onto a sd card and it booted up just fine. I recharged the questionable battery to 100%. I launched the EVO 2 PRO 3' off the carpet. I recorded the voltage on the 3 cells every 5%. Here are the results:

100% 4.344 4.314 4.325
99 % 4.326 4.298 4.309
95 % 4.112 4.200 4.169
90 % 4.067 3.977 4.028
85 % 4.025 3.933 3.998
80 % 3.986 3.886 3.936
75 % 3.943 3.842 3.892
70 % 3.905 3.797 3.852
65 % 3.866 3.762 3.812
60 % 3.832 3.723 3.777
55 % 3.799 3.693 3.746
50 % 3.769 3.666 3.721
45 % 3.741 3.643 3.692
40 % 3.718 3.625 3.673
35 % 3.697 3.609 3.657
30 % 3.678 3.589 3.642
25 % 3.665 3.554 3.621
20 % 3.653 3.457 3.586
17 % 3.643 3.313 3.559
16 % 3.638 3.228 3.546
15 % 3.632 3.140 3.529
14 % 3.627 3.077 3.511
13 % 3.626 2.990 3.490
12 % 3.623 2.929 3.472
11 % 3.617 2.850 3.344
10% auto land at 0% flight time 26m1s battery temp 57.6C

So the flight time was shorter. At 10% the battery showed 0% and I had to land. Landing was swift and firm. As previously posted, I contacted Autel last Thursday and I have not heard from them yet....
your thoughts folks .....

Your middle Cell is highly unbalanced. Is normal to have a difference of 0.2V between cells, but not 0.8V, this is huge...Also is strange that 1st cell is not going down with the rest...Is not compensating...
Give a mail to Autel and request to change the battery, is unpredictable as if one cell collapse, you can experience from sudden crash to forced landing(that is the happiest version).
Cheers.

 

[moodman]

I went ahead and created a voltage chart for you so that you can see what is really happening. In this graph, notice first that there are steep dropoffs on all cells in the first four periods. Then things smooth out. But then, when it gets to about period 17, cell two really drops off dramatically. But cell three also has some issues, just not as dramatic. Cell one seems pretty healthy, but you definitely have issues with cell two. It's also odd that cell three drops off sharply right before the end...

 

[GeoDrone SRL]

I went ahead and created a voltage chart for you so that you can see what is really happening. In this graph, notice first that there are steep dropoffs on all cells in the first four periods. Then things smooth out. But then, when it gets to about period 17, cell two really drops off dramatically. But cell three also has some issues, just not as dramatic. Cell one seems pretty healthy, but you definitely have issues with cell two. It's also odd that cell three drops off sharply right before the end...
View attachment 12919

It can also be the balancing circuit that is failing, as it does not compensate from cell 1 (is like is cutting the power drain from cell 1 from a reason, as it cannot be so flat)...

 

[Ungava]

Just my opinion....but I really think you are wasting a lot of time on something that shouldn't be your problem...its an Autel problem and the battery is within warranty so what I would do is take it out of the rotation, never use it again and hound Autel for warranty support. I would not risk a $2000 drone over a $200 battery not to mention if the drone falls out of the sky and injures someone one on the ground or damages some property you could be looking at a lot more than that.

Additionally, LiPo batteries are very combustible so a problem like that could end in a battery fire or worse. I don't take any chances with LiPos; so I would follow whatever guidance Autel gave me to the letter and keep all communication in writing between yourself and Autel in case that battery ends up causing real damage or your loss of the drone.

I agree with you 100%. I will never use this battery again. I can not trust it but safety and getting my drone back are the priorities.
Just so everyone knows, ... I have contacted Autel several times over the past 9 days by email and they have not answered me yet. I have also called several times and I have not been able to get thru to the company. Keep getting message they cannot answer at this time. I will not give up on this issue but I'm not impressed so far...

 

[Ungava]

Your middle Cell is highly unbalanced. Is normal to have a difference of 0.2V between cells, but not 0.8V, this is huge...Also is strange that 1st cell is not going down with the rest...Is not compensating...
Give a mail to Autel and request to change the battery, is unpredictable as if one cell collapse, you can experience from sudden crash to forced landing(that is the happiest version).
Cheers.

Thanks ... see my other replies.... nothing from Autel yet..

 

[Ungava]

It can also be the balancing circuit that is failing, as it does not compensate from cell 1 (is like is cutting the power drain from cell 1 from a reason, as it cannot be so flat)...

Gee. Thanks a lot. with your permission, I'll use this to send to Autel .... if they get back to me ... 9 days and no response yet ...

 

[Ungava]

I went ahead and created a voltage chart for you so that you can see what is really happening. In this graph, notice first that there are steep dropoffs on all cells in the first four periods. Then things smooth out. But then, when it gets to about period 17, cell two really drops off dramatically. But cell three also has some issues, just not as dramatic. Cell one seems pretty healthy, but you definitely have issues with cell two. It's also odd that cell three drops off sharply right before the end...
View attachment 12919

I did not record the V after 11% as the controller instantly went to 0% and the drone made a firm landing.

 

[Ungava]

I will for sure...

After more than 2 weeks trying to contact Autel via phone and email, received a reply by email. explained the battery issue. They asked for more info so I sent the voltage data I accumulated during my indoor tests. They accepted the data and issued a PO free of charge for a new battery. I am happy about that.
Thanks for everyone's suggestions and help....
Autel is either short staffed or overwhelmed with service requests...

 

[Ungava]

I did not record the V after 11% as the controller instantly went to 0% and the drone made a firm landing.

thanks moodman for your efforts. you were a great help

 

[Eagle's Eye Photo]

Rather than retiring the out of balance battery... mark it as such and then limit it's use to non-flight operations... calibrations, sitting to update the GPS almanac if you haven't flown in a while, etc. That way, you can maximize your flight cycles of your other batteries.

 

[Ungava]

Rather than retiring the out of balance battery... mark it as such and then limit it's use to non-flight operations... calibrations, sitting to update the GPS almanac if you haven't flown in a while, etc. That way, you can maximize your flight cycles of your other batteries.

Another great idea.... thanks... I'll be doing that

 

[smokeygt]

Mine doing the same thing. Anything definitive on a solution?

 

[Sjs]

OK. I downloaded the FW BIN onto a sd card and it booted up just fine. I recharged the questionable battery to 100%. I launched the EVO 2 PRO 3' off the carpet. I recorded the voltage on the 3 cells every 5%. Here are the results:

100% 4.344 4.314 4.325
99 % 4.326 4.298 4.309
95 % 4.112 4.200 4.169
90 % 4.067 3.977 4.028
85 % 4.025 3.933 3.998
80 % 3.986 3.886 3.936
75 % 3.943 3.842 3.892
70 % 3.905 3.797 3.852
65 % 3.866 3.762 3.812
60 % 3.832 3.723 3.777
55 % 3.799 3.693 3.746
50 % 3.769 3.666 3.721
45 % 3.741 3.643 3.692
40 % 3.718 3.625 3.673
35 % 3.697 3.609 3.657
30 % 3.678 3.589 3.642
25 % 3.665 3.554 3.621
20 % 3.653 3.457 3.586
17 % 3.643 3.313 3.559
16 % 3.638 3.228 3.546
15 % 3.632 3.140 3.529
14 % 3.627 3.077 3.511
13 % 3.626 2.990 3.490
12 % 3.623 2.929 3.472
11 % 3.617 2.850 3.344
10% auto land at 0% flight time 26m1s battery temp 57.6C

So the flight time was shorter. At 10% the battery showed 0% and I had to land. Landing was swift and firm. As previously posted, I contacted Autel last Thursday and I have not heard from them yet....
your thoughts folks .....

My middle cell on my 2 oldest batteries (my 1st 130 to 140 charges) according to smart controller the middle cells are a tenth lower but my number 1 battery went nuts and took my bird into peaple and almost lost it just went completely dead in a instant. Temps are running 20 degrees higher for the almost same type of flights compared to the new ones I bought .