Battery Failure

[Videolabtv]

Hi all, I have had 2 situations where my drone just fell from the sky.
Situation 1. I was flying my Skydio 2 drone for ten minutes when suddenly without warning it fell from the sky onto my driveway. It was smashed and not repairable. I reported it to skydio and was told after investigation that the motherboard had a catastrophic failure and the warranty was no good because it was over a year.

I still think Skydio is the best drone pound for pound so I bought a new Skydio2+. I was using the first skydo2 batteries when the drone fell from the sky again. This time I was lucky and it fell from 30ft into bushes and was not destroyed.

I decided to test the batteries by fully charging them and allowing the drone to hover 2 ft of the grown with a rug underneath for security. 2 of the batteries lasted about 10-15 minutes and the drone fell to the grown without warning.

Please test your batteries because there is no returning to home. Just a major crash from the sky.

The question is how to care for the batteries to keep them in good shape. Should they be fully charged and put away or drained and put away.

 

[VEGASROBBI]

Check the surface of the battery that is against the drone, it should be perfectly flat. I had a couple of batteries that swelled and about 10 minutes into the flight they would cause a disconnect and my S2 fell from the sky.

Since discarding the swelled batteries I've had no issues.

 

[Videolabtv]

You are correct they are slightly swollen. Just throw them out. How do you care for the battery to avoid swelling

 

[Ridefreak]

I need to do this, 5 of my 6 batteries were bought when the SD2 came out or shortly after. I've had one go bad so far, luckily the beacon said the battery was bad and wouldn't take off with it. I have taken the step to check and made sure they're all updated and a couple weren't. They will update themselves just by using them but I took the extra step to do it w/o flying just in case. I'm sure a couple of mine are down to 15min duration. I need to buy some new ones.

 

[lidocaineus]

Check the surface of the battery that is against the drone, it should be perfectly flat. I had a couple of batteries that swelled and about 10 minutes into the flight they would cause a disconnect and my S2 fell from the sky.

Since discarding the swelled batteries I've had no issues.

If you can, it's highly preferable to recycle the batteries properly (just google for it in your area, often times your city will take them). LiPos can be volatile, and when they're swollen they're definitely in that state. I would actually suggest you keep them in a fireproof container until you can recycle them properly.

For all LiPos and LiIons you should regularly run them down to where the Skydio says it will need to land soon (better if you can run it until it forces a landing). After they've cooled down, charge them all the way up to 100% and leave them charging for about 30 minutes at least after it says full to make sure the cells are balanced. If you aren't flying right away, charge them to ~40-50% for storage, and charge them up to full before you fly them. This last part isn't strictly necessary since the batteries are designed to discharge down to 40% if not used after a period of time, but it's basically a tiny bit of unnecessary stress on the batteries and a waste of energy. Don't just keep them topped up all the time, as that really shortens the battery pack's life and could lead to battery issues due to imbalances.

 

[VEGASROBBI]

Battery maintenance is a good question. I've been flying drones for over a decade and in the old days it was just a matter of time before battery's swelled.

Someone else can chime in but my understanding is you need to think of a battery like a balloon, when it is fully discharged or fully charged it's putting stress on the battery. So you want a neutral charge about 50%. I noticed most batteries ship at about 50% and most manufacturers recommend storing at about 50%. Many batteries, including Skydio should self-discharge to about 50% automatically.

I am guilty of charging a battery then not flying for a few days, and sometimes out here in Vegas temps can be well over a hundred degrees inside the car so I'm sure that's stressful on the battery. Since my incident with the batteries I have taken more care to charge them to 50% and keep them stored at that level and only charge them fully when I'm going to fly. So far my three new batteries have held up well with no signs of swelling; but as soon as I see swelling I will discard the battery because I noticed that it swells during flight especially in the higher temperatures and you can't monitor that.

 

[Ridefreak]

If you can, it's highly preferable to recycle the batteries properly (just google for it in your area, often times your city will take them). LiPos can be volatile, and when they're swollen they're definitely in that state. I would actually suggest you keep them in a fireproof container until you can recycle them properly.

For all LiPos and LiIons you should regularly run them down to where the Skydio says it will need to land soon (better if you can run it until it forces a landing). After they've cooled down, charge them all the way up to 100% and leave them charging for about 30 minutes at least after it says full to make sure the cells are balanced. If you aren't flying right away, charge them to ~40-50% for storage, and charge them up to full before you fly them. This last part isn't strictly necessary since the batteries are designed to discharge down to 40% if not used after a period of timeb, but it's basically a tiny bit of unnecessary stress on the batteries and a waste of energy. Don't just keep them topped up all the time, as that really shortens the battery pack's life and could lead to battery issues due to imbalances.

That extra half hour isn't doing anything, I routinely monitor the power when the battery is charging, the watt display is built right into the cable I use. When the 4 bars go solid (full charge) the battery's BMS shuts the charge down. Power drops to 1~2 watts as the battery approaches full charge and goes to zero when all 4 go solid. Nothing is happening after all 4 lights illuminate.

 

[Ridefreak]

Hi all, I have had 2 situations where my drone just fell from the sky.
Situation 1. I was flying my Skydio 2 drone for ten minutes when suddenly without warning it fell from the sky onto my driveway. It was smashed and not repairable. I reported it to skydio and was told after investigation that the motherboard had a catastrophic failure and the warranty was no good because it was over a year.

I still think Skydio is the best drone pound for pound so I bought a new Skydio2+. I was using the first skydo2 batteries when the drone fell from the sky again. This time I was lucky and it fell from 30ft into bushes and was not destroyed.

I decided to test the batteries by fully charging them and allowing the drone to hover 2 ft of the grown with a rug underneath for security. 2 of the batteries lasted about 10-15 minutes and the drone fell to the grown without warning.

Please test your batteries because there is no returning to home. Just a major crash from the sky.

The question is how to care for the batteries to keep them in good shape. Should they be fully charged and put away or drained and put away.

During that time the drone wasn't used were the batteries ever topped off? Asking because the discharge rate while slow is something to be aware of, SD has a process where the battery discharges to 50% after 2 weeks of no use but they have no way of addressing the other end of the spectrum; discharge. Leaving or letting one of these discharge and remain that way is as detrimental as having one sit fully charged, It will reduce the batteries persistence (ability to hold a charge) flight duration and it's remaining charge cycles.

 

[lidocaineus]

That extra half hour isn't doing anything, I routinely monitor the power when the battery is charging, the watt display is built right into the cable I use. When the 4 bars go solid (full charge) the battery's BMS shuts the charge down. Power drops to 1~2 watts as the battery approaches full charge and goes to zero when all 4 go solid. Nothing is happening after all 4 lights illuminate.

BMS balance chargers are often 1 or 2 watts. Sometimes even less, as balance circuits are often extremely low powered. Either way, you’re not hurting the battery pack, and you’re hardly wasting any time doing this occasionally.

 

[lidocaineus]

During that time the drone wasn't used were the batteries ever topped off? Asking because the discharge rate while slow is something to be aware of, SD has a process where the battery discharges to 50% after 2 weeks of no use but they have no way of addressing the other end of the spectrum; discharge. Leaving or letting one of these discharge and remain that way is as detrimental as having one sit fully charged, It will reduce the batteries persistence (ability to hold a charge) flight duration and it's remaining charge cycles.

Wait, are you sure? The self discharge is limited to roughly around 40%, followed by entering deep sleep mode if left untouched for longer periods of time. That means it never drops its own voltage beyond an unchargeable state; probably the only way to actually get it there is run the pack to its absolute limit where it forces
you to land, and then don’t charge it all, AND keep waking it from deep sleep mode. Even then it’d be a pretty long process.

 

[VEGASROBBI]

Overtime the batteries will go flat. I purchased a dozen spare 3DR batteries for my Solo and if I don't charge them every few months they will slowly discharge to zero.

I think the lesson learned here is store the batteries at 40 to 50% capacity and charge them fully when you're ready to fly. I feel leaving them fully charged for 2 weeks is stressing them out, especially in extreme temperatures. I like to leave my batteries in my office where the temperature is somewhat regulated. But sometimes I intend to fly and leave my drone in the Jeep and during the winter that can drop below freezing or be well in excess of 100° and I don't think that's good practice

Since I've implemented this practice I've had no battery failures nor signs of swelling.

I do believe the Skydio batteries are a step above, the charger seems sophisticated enough to balance charge the batteries in a reasonable amount of time. As Ridefreak discovered early on the Skydio batteries prefer higher voltage and sufficient current. My guess is the battery maintenance system board is in the battery not in the charger but I'm not sure. I sure don't miss the days of balance plugs and aftermarket chargers that was a rat nest of wiring.

 

[Ridefreak]

Wait, are you sure? The self discharge is limited to roughly around 40%, followed by entering deep sleep mode if left untouched for longer periods of time. That means it never drops its own voltage beyond an unchargeable state; probably the only way to actually get it there is run the pack to its absolute limit where it forces
you to land, and then don’t charge it all, AND keep waking it from deep sleep mode. Even then it’d be a pretty long process.

I don't know the exact percentage, I do know like clockwork after 2 weeks all the batteries drop to 2 bars. They will remain at that point for a couple months before eventually discharging further.

"

• If the battery is above 60% state of charge, after 14 days of idle time (no flights) it will start to self-discharge down to approx. 60%. This self-discharge helps retain capacity over the life of the battery and may take several days to complete. Charge your battery as you would normally to exit this idle state.

 

[kgilbertsen]

When your battery loses power

 

[Ridefreak]

very nice save!