Battery died in the air...

[MJ224]

Phew, had a close shave today. Drone battery just conked out after a couple of minutes flying. I did check the capacity just before take off, 4 lights....

It also conked out over a large pond, but I was able to fly the drone to solid ground luckily.

I had another couple of good batteries to finish the project and they just worked fine.

The battery in question is about two years old, and I have another of the same age. Will have to be careful on the next flights, and see if the problem is the battery, or me...

 

[Flippigan]

When was the last time the at fault battery had been charged before it was used for the flight? What can happen is if the battery sits for over a week is the self discharge feature can kick in and begin draining the battery. When this happens the percentage displayed does not change however it is loosing capacity. Resulting in an over estimation of how much is remaining by the power management system and many crashes. Your not the first person this has happened to and you won’t be the last happened to me a few months ago and I will never forget this feature exists.

 

[Kilrah]

Air 1 batteries are known not to age well and a lot of them being unusable by now.

 

[rawman001]

When was the last time the at fault battery had been charged before it was used for the flight? What can happen is if the battery sits for over a week is the self discharge feature can kick in and begin draining the battery. When this happens the percentage displayed does not change however it is loosing capacity. Resulting in an over estimation of how much is remaining by the power management system and many crashes. Your not the first person this has happened to and you won’t be the last happened to me a few months ago and I will never forget this feature exists.

Are you saying when you press the button on the battery, and it shows 4 lights, it still could be dead?

 

[Flippigan]

Are you saying when you press the button on the battery, and it shows 4 lights, it still could be dead?

The actual charge of the battery can be up to 40% less than the displayed charge. All Lipo batteries are best kept at near 50% charge, so DJI built in a feature called “self discharge” that will begin self discharging the battery after a preset amount of time after being plugged in or flown. You can adjust this amount of time in the DJI GO app. The best way to ensure you have a full battery is to charge it and fly within 2 days of that charge.

 

[rawman001]

The actual charge of the battery can be up to 40% less than the displayed charge. All Lipo batteries are best kept at near 50% charge, so DJI built in a feature called “self discharge” that will begin self discharging the battery after a preset amount of time after being plugged in or flown. You can adjust this amount of time in the DJI GO app. The best way to ensure you have a full battery is to charge it and fly within 2 days of that charge.

Yes I'm familiar with the "self discharge". My question is about the indicator lights on the top of the battery. Don't the lights on the top of the battery show if the battery is fully charged? If all 4 lights are on, can the battery still be at 40%???

 

[Flippigan]

Yes I'm familiar with the "self discharge". My question is about the indicator lights on the top of the battery. Don't the lights on the top of the battery show if the battery is fully charged? If all 4 lights are on, can the battery still be at 40%???

Yes

 

[rawman001]

Yes

Thank you. I had no idea. Is this defect specific to Air 1 battery, or would it apply to A2s batteries as well?

 

[Flippigan]

Thank you. I had no idea. Is this defect specific to Air 1 battery, or would it apply to A2s batteries as well?

I believe it applies to all DJI batteries as of Dec 2021, if a DJI battery is allowed to self discharge the displayed percentage will not change, however it will be loosing useable capacity unless charged again.

 

[Kilrah]

The LEDs display the estimated charge based on capacity and many other factors. But if capacity has dropped significantly since the last full cycle it can be off, and if the capacity is there but the cells' internal resistance has degraded enough to cause a large voltage drop then it will also cause percentage to drop like a rock.

I believe it applies to all DJI batteries as of Dec 2021, if a DJI battery is allowed to self discharge the displayed percentage will not change, however it will be loosing useable capacity unless charged again.

That's very wrong.

All DJI batteries behave the same though, but the ones for the Air 1 happen to age/degrade more quickly than most others.

 

[rawman001]

I believe it applies to all DJI batteries as of Dec 2021, if a DJI battery is allowed to self discharge the displayed percentage will not change, however it will be loosing useable capacity unless charged again.

The batteries on my A2s have always displayed 3 out of 4 lights on when they've self discharged after not being flown for a while.

 

[rawman001]

The LEDs display the estimated charge based on capacity and many other factors. But if capacity has dropped significantly since the last full cycle it can be off, and if the capacity is there but the cells' internal resistance has degraded enough to cause a large voltage drop then it will also cause percentage to drop like a rock.


That's very wrong.

All DJI batteries behave the same though, but the ones for the Air 1 happen to age/degrade more quickly than most others.

Thanks, that makes sense.

 

[snowghost]

Let's say 4 lights, 40% charge in reality. If you look at the battery in the Go 4 or Fly App will it show the 40%?

 

[Flippigan]

It’s situational, age of the battery, length of “self discharge”, outside temperature and time since last charge are all factors. To make sure your battery percentage is accurate charge the battery AT MOST 2 days before a flight. If it sits for longer than 2 days charge it again before flying with it.

 

[Kilrah]

Let's say 4 lights, 40% charge in reality. If you look at the battery in the Go 4 or Fly App will it show the 40%?

No. If the 4 lights light up steady the battery's BMS considers it's >88%, and thus tells the drone that same value.

Once there is some load on the battery that may get reevaluated but they'll always say the same.

 

[snowghost]

No. If the 4 lights light up steady the battery's BMS considers it's >88%, and thus tells the drone that same value.

Once there is some load on the battery that may get reevaluated but they'll always say the same.

Good reason to check the cell levels before and just after liftoff in a low hover.

 

[JoelP]

I own the MA1 and have experienced a couple of battery failures. A recent flight almost cost me the drone. As a result I have studied the problem.

Let me begin by saying that I always store my batteries at room temperature at just above 50%, but they still degrade. The one thing that I failed to do is fly every battery at least once every 3 months, which I have heard causes degradation.

So, how can you tell if the battery is compromised? The batteries can look fully charged with 4 lights. The controller can say it is 95% charged or more and it still can be compromised. You can look at the voltage of the 3 cells and they will look in the Go 4 app to be fully balanced before you take off. But, when you take off and hover a few feet off them ground you will see that the cells have notably different voltage! That is a compromised battery and should not be flown over a pond or other places where a forced landing will be an issue.

The other issue is replacing a compromised MA1 battery. They aren’t available from DJI. You might find some at a steep price in distribution. Perhaps it’s time to look for a new drone if you have too many batteries in that state.

 

[Squidinc]

Good reason to check the cell levels before and just after liftoff in a low hover.

I always charge my three Air2 batteries on the night before a morning flight. Have never had an issue so far, but learnt something here tonight re the two day window for charging. I always check the battery level in the fly app on take off.

 

[MJ224]

Thanks all for views and advice. Now that I think back, I am uncertain when I last charged that battery. It definitely showed four lights, so maybe I thought it did not need charging. Slightly surprised y that, as the three batteries I have always seem to show two to three lights if not recently used/charged.

I had used the drone several days before, but only used one battery.

Yes the Air 1 batteries are difficult to source, I paid £90 for the last one, from Lithuania...Maybe time to look at the mini 2..

I use the drone to produce Photo Mosaics for a couple of Charities that I volunteer for. Litchi works so well there, I am unsure what other drones can use Litchi...

Thanks again..

 

[Kilrah]

Batteries put themselves at storage level after a few days and the LEDs will reflect that so you did charge it recently.