Sudden Battery Power Loss

[redleger]

Today on a job I had something happen that has never happened before. First battery in, everything checks out, so I do my normal routing. Hover about 30 seconds at shoulder height, and wait to see if anything is wrong. No issues, so I head to 400ft AGL to get the initial shot which is a birds eye view. No sooner than I get the camera pointed down, does an alarm go off and my batter shows 0%. Was 100% and at less than 2 minutes of flight time. I immediately began dropping the drone and heading back to my take off position. I made it down to 2 feet and was about 10 feet away from it's landing spot when it just quit responding and gently lowered itself down and landed.

Finished the job with other batteries no issue. Got home. Charged bad battery, took it out back and hovered it at 40 feet for 5 minutes, no issue. Then up to 400 feet, no issues for 5 minutes. Landed it no issues.

Has anyone ever had that happen to them? If so is there a cause? I know some jamming can cause battery levels to drop, but I never lost control.

 

[herein2021]

Today on a job I had something happen that has never happened before. First battery in, everything checks out, so I do my normal routing. Hover about 30 seconds at shoulder height, and wait to see if anything is wrong. No issues, so I head to 400ft AGL to get the initial shot which is a birds eye view. No sooner than I get the camera pointed down, does an alarm go off and my batter shows 0%. Was 100% and at less than 2 minutes of flight time. I immediately began dropping the drone and heading back to my take off position. I made it down to 2 feet and was about 10 feet away from it's landing spot when it just quit responding and gently lowered itself down and landed.

Finished the job with other batteries no issue. Got home. Charged bad battery, took it out back and hovered it at 40 feet for 5 minutes, no issue. Then up to 400 feet, no issues for 5 minutes. Landed it no issues.

Has anyone ever had that happen to them? If so is there a cause? I know some jamming can cause battery levels to drop, but I never lost control.

Yes, this has happened to me twice, the first time it was very cold and the remaining battery went from 100% to less than 10% within a few minutes, and the second time I had not properly seated the battery on the charger so it did not balance all 3 cells properly. The battery showed 100% using the indicator lights, it also showed 100% in the app, but within a few min in the air it suddenly dropped to 5% and I almost lost the drone.

You did not mention if you had fully charged the battery that day before using it. If you put away a multi-cell LiPo at 100% charge, even if it shows 100% later on, you have to put it back on the charger and wait for the flashing lights to go out to ensure it is properly balanced. I would estimate it takes about 12-24hrs for a multi-cell LiPo to possibly become unbalanced which will cause the problem that you experienced.

 

[redleger]

Yes, this has happened to me twice, the first time it was very cold and the remaining battery went from 100% to less than 10% within a few minutes, and the second time I had not properly seated the battery on the charger so it did not balance all 3 cells properly. The battery showed 100% using the indicator lights, it also showed 100% in the app, but within a few min in the air it suddenly dropped to 5% and I almost lost the drone.

You did not mention if you had fully charged the battery that day before using it. If you put away a multi-cell LiPo at 100% charge, even if it shows 100% later on, you have to put it back on the charger and wait for the flashing lights to go out to ensure it is properly balanced. I would estimate it takes about 12-24hrs for a multi-cell LiPo to possibly become unbalanced which will cause the problem that you experienced.

I had fully charged the batteries 48 hours prior to flight. It was exactly as you described, 100% on the lights, and the app upon connecting controller to AC. When properly charged, is this something that can be rectified and safely flown with?

 

[herein2021]

I had fully charged the batteries 48 hours prior to flight. It was exactly as you described, 100% on the lights, and the app upon connecting controller to AC. When properly charged, is this something that can be rectified and safely flown with?

If it is due to being unbalanced then yes. One thing you can do is take the props off of the EVO, put the "bad" battery in it, turn on the drone, and leave it like that sitting indoors until the battery completely dies; it will probably take a few hours. After that, put the battery on the charger and let it fully recharge. This will reset the balancing circuitry and hopefully fully charge and rebalance it.

I would still mark that battery and always use it with extreme caution (i.e. not over people, cars, water, lengthen your takeoff procedure with that battery, etc.). I marked the battery that almost caused me to lose my drone but it was 100% my fault, it just wasn't seated properly on the charger. It has now been almost a year later and it still works flawlessly.

Even 48hrs prior would not be safe in my opinion, if I have a job 48hrs in the future then I put the batteries on the charger the night before, or if it is later in the day then if possible I put them on the charger that morning and don't take them off until I am heading out to the jobsite. LiPos are very finicky especially as they age and there are so many hobbyists who lose their drones because they don't understand the complexities of their batteries. As commercial pilots, we should go the extra mile because we have more on the line if something goes wrong.

 

[redleger]

If it is due to being unbalanced then yes. One thing you can do is take the props off of the EVO, put the "bad" battery in it, turn on the drone, and leave it like that sitting indoors until the battery completely dies; it will probably take a few hours. After that, put the battery on the charger and let it fully recharge. This will reset the balancing circuitry and hopefully fully charge and rebalance it.

I would still mark that battery and always use it with extreme caution (i.e. not over people, cars, water, lengthen your takeoff procedure with that battery, etc.). I marked the battery that almost caused me to lose my drone but it was 100% my fault, it just wasn't seated properly on the charger. It has now been almost a year later and it still works flawlessly.

Even 48hrs prior would not be safe in my opinion, if I have a job 48hrs in the future then I put the batteries on the charger the night before, or if it is later in the day then if possible I put them on the charger that morning and don't take them off until I am heading out to the jobsite. LiPos are very finicky especially as they age and there are so many hobbyists who lose their drones because they don't understand the complexities of their batteries. As commercial pilots, we should go the extra mile because we have more on the line if something goes wrong.

All great advice. I will take more caution and plan better for my battery use. Thank you.

 

[TTomsu]

My Evo II V2 did almost the same thing yesterday. I was on the first battery of a 60 minute mission. At 25% it executed an automatic return to home for a battery change. At +/-20%, alarm goes off and it shows 0% battery. I can see the drone automatically landing from it's 200' AGL. At approximately 20', it fell to the ground and ruined 1 prop and I am getting an error for the rear obstacle avoidance camera. Flew 3 more batteries to complete the mission without anymore problems (other than the camera error). Charged the battery that failed to 50% and did a hover test. Battery ran just fine until 19% and did the exact same thing. Dropped to 0% immediately and and landed. I have had other drone batteries go from 100% to nothing very quickly after takeoff, but never a battery act as normal (flight time as expected for current conditions) until it gets to 20%. I will try to balance the battery and conduct more hover test with this battery, just to see if it can be fixed. But I will probably never trust it again and junk it.

 

[redleger]

My Evo II V2 did almost the same thing yesterday. I was on the first battery of a 60 minute mission. At 25% it executed an automatic return to home for a battery change. At +/-20%, alarm goes off and it shows 0% battery. I can see the drone automatically landing from it's 200' AGL. At approximately 20', it fell to the ground and ruined 1 prop and I am getting an error for the rear obstacle avoidance camera. Flew 3 more batteries to complete the mission without anymore problems (other than the camera error). Charged the battery that failed to 50% and did a hover test. Battery ran just fine until 19% and did the exact same thing. Dropped to 0% immediately and and landed. I have had other drone batteries go from 100% to nothing very quickly after takeoff, but never a battery act as normal (flight time as expected for current conditions) until it gets to 20%. I will try to balance the battery and conduct more hover test with this battery, just to see if it can be fixed. But I will probably never trust it again and junk it.

Yea, an untrustworthy battery makes you pucker up for sure if you know what I mean.