Battery Damage Notification. Seems ok after ground test. Advice needed

[Honda_impreza]

Hi all

Gday from Brisbane Australia.

Today I took the P3s out over the river. Quite a warm day, perhaps 33 degrees Celsius and very high humidity, but clear skies with 25km/h winds. Flight went well at and altitude of around 100m. Bird was launched with a full battery and has done 29 charge cycles (purchased new in October if i remember correctly). However, after eight minutes I got "Damaged Battery" warning on top centre of device screen. I initiated RTH and then manually landed as I usually do and also due to the fact I launched from a clearing surrounded by 4m metre tall trees.

Later I did two tests with props off. Battery seems ok. I took a reading of battery data, which is as follows:

around 58 percent charge

far left cell: 3.87v
2nd cell: 3.92v
3rd cell: 3.91v
far right cell: 3.91v
Voltage 15.62v

remaining power: 2390mAh
total capacity: 4194mAh


My question is what is the next course of action? Thanks in advance.

 

[120CCPM]

Never used it, but Airdata UAV does an analysis of your battery and gives you an indication of how severe is the problem: Airdata UAV - Flight Data Analysis for Drones

The P3S battery has a rather basic cell balancer built-in, so it might not be able to fully charge a cell that is slightly weaker than the others. In flight, that cell will discharge sooner than the others, and that could trigger the warning.
You can try topping off the battery after it's fully charged: let it rest for an hour or so, then turn it on (as you would to power on the AC) and connect it to the charger while it's on. Unlikely, but it might be enough.

In any case, a weak cell doesn't mean that the battery will explode on the next flight, but you definitely need to keep it under observation. In particular, avoid discharging the battery too much, as that would cause the weak cell to reach dangerously low voltages, which in turn would further damage it. So on your next flight, stay on the safe side and land with 40% battery or so, then check on Airdata what type of voltage delta you have on the 4 cells.

If it's severe, unfortunately you might need a new battery.

PS: I believe DJI at some point was recommending a periodic full discharge of the P3 batteries, followed by a full charge, for the built-in electronics to give an accurate capacity reading. I never looked into that, but I think it's a controversial topic, with people saying it does absolutely nothing. If it were me, before throwing away a $100 battery, I'd still give it a shot.

 

[With The Birds]

Reported capacity is low for the number of charge cycles, I would expect to see closer to 4400mah for a battery in good condition.

It is likely you have one cell that with increased IR.

Have you allowed the pack to sit at or close to full depletion for any period of time? Joey at full charge? Routinely down down to less than 10% SOC?

Upload your flight to airdata and post a link for the flight where the error was reportedso we can take a look.

 

[Honda_impreza]

Reported capacity is low for the number of charge cycles, I would expect to see closer to 4400mah for a battery in good condition.

It is likely you have one cell that with increased IR.

Have you allowed the pack to sit at or close to full depletion for any period of time? Joey at full charge? Routinely down down to less than 10% SOC?

Upload your flight to airdata and post a link for the flight where the error was reportedso we can take a look.

Cheers and thanks for the reply.

There have been periods where ive let it sit at full charge for a few days. However, i do not routinely let it go too low. Rarely if ever down to 10% or less. Whats SOC?

Im still a bit of a newbie and im yet to get my head around updating flight logs. I ought to check out airdata

 

[With The Birds]

Cheers and thanks for the reply.

There have been periods where ive let it sit at full charge for a few days. However, i do not routinely let it go too low. Rarely if ever down to 10% or less. Whats SOC?

Im still a bit of a newbie and im yet to get my head around updating flight logs. I ought to check out airdata

State of charge

 

[Honda_impreza]

State of charge

Roger that.

May I ask... will the free version on airdata provide the necessary data?

On a side note, battery is still under warranty. I called DJI Australia and spoke to two operators. The first said to discharge battery and recharge. The second told me to re-upload/update firmware on the bird via micro SD. I don't know if their advice was any use.

 

[Neon Euc]

Def give airdata a go. It tells you what problems you have on each cell (it highlights it red) its free to use (unless you want to pay for more advanced data) but I use the free version and it's way more then enough for me. Don't forget to copy and paste the token code your given into litchi (if you have that) and select automatic syn to. You need to download an app called HD sync in order to do this

 

[120CCPM]

On a side note, battery is still under warranty. I called DJI Australia and spoke to two operators. The first said to discharge battery and recharge. The second told me to re-upload/update firmware on the bird via micro SD. I don't know if their advice was any use.

If it's under warranty, have it replaced. Have you tried what I told you (fully charge it, then top it off)?

 

[Honda_impreza]

If it's under warranty, have it replaced. Have you tried what I told you (fully charge it, then top it off)?

Yes, I did this.

Perhaps I could just ask to get it replaced. I actually ordered a second battery off eBay which should arrive in the next week. In any case, it's good to have more than one battery.

I've done two full discharges with low-level flights and battery seems OK with no warnings coming up. mAh is now up to 4248 total capacity. Last flight the battery went up to 58 celcius temp before landing at 7% charge (i did a lot of full-throttle backwards and forwards runs on a football field) However, according to forum posts it seems this temperature is not abnormal.


I still haven't tried airdata, and I'm unfamiliar with Litchi. Can airdata work with the DJI go app?

 

[With The Birds]

Yes, I did this.

Perhaps I could just ask to get it replaced. I actually ordered a second battery off eBay which should arrive in the next week. In any case, it's good to have more than one battery.

I've done two full discharges with low-level flights and battery seems OK with no warnings coming up. mAh is now up to 4248 total capacity. Last flight the battery went up to 58 celcius temp before landing at 7% charge (i did a lot of full-throttle backwards and forwards runs on a football field) However, according to forum posts it seems this temperature is not abnormal.


I still haven't tried airdata, and I'm unfamiliar with Litchi. Can airdata work with the DJI go app?

Yes- go to the airdata website and you will find instructions for uploading your flight logs.

 

[BigAl07]

before landing at 7% charge (i did a lot of full-throttle backwards and forwards runs on a football field) However, according to forum posts it seems this temperature is not abnormal.

You're flirting with disaster running a "suspect" battery so low. Keep in mind that if you lose a cell your aircraft will power down and come back to Terra Firma without any control from you.

 

[Honda_impreza]

You're flirting with disaster running a "suspect" battery so low. Keep in mind that if you lose a cell your aircraft will power down and come back to Terra Firma without any control from you.

This was a complete non issue because i discharged with the bird one metre up the whole time and over grass.

I was reading in another thread that if a cell gets below 3.0v the battery DJI programs it to shut down for its own protection. That's stupidly hilarious and terrifying at the same time.

 

[With The Birds]

This was a complete non issue because i discharged with the bird one metre up the whole time and over grass.

I was reading in another thread that if a cell gets below 3.0v the battery DJI programs it to shut down for its own protection. That's stupidly hilarious and terrifying at the same time.

It’s not ridiculous when you understand what is happening. The 3V threshold is programmed into the TI BMS SOC (it was originally 3.2V). The fuel gauge and health algorithms will report an issue with the battery well before you hit the low voltage on any cell, even before an error message you will see the remaining capacity and estimated flight time to empty accurately reflecting the health and remaining capacity of the battery without you having to think about it.

With dumb lipos in other RC aircraft you get no warning, hit the low voltage cutout and it’s all over without warning.

In any case, hit 3V on one cell even without the protection cutout and your likely very close to the all over point.

 

[Honda_impreza]

It’s not ridiculous when you understand what is happening. The 3V threshold is programmed into the TI BMS SOC (it was originally 3.2V). The fuel gauge and health algorithms will report an issue with the battery well before you hit the low voltage on any cell, even before an error message you will see the remaining capacity and estimated flight time to empty accurately reflecting the health and remaining capacity of the battery without you having to think about it.

With dumb lipos in other RC aircraft you get no warning, hit the low voltage cutout and it’s all over without warning.

In any case, hit 3V on one cell even without the protection cutout and your likely very close to the all over point.

Thanks for all the help With the Birds

On another note, today I got onto airdata and got to upload the offending flight when the warning was triggered. I can't find where the battery damaged warning was triggered, but I initiated RTH not long after and later turned off RTH and manually descended and landed the last 30 metres or so. Airdata battery cell shows what appears to my untrained noob eyes to be a massive amount of major deviations.

Airdata UAV - Flight Data Analysis for Drones

 

[Honda_impreza]

And here's last night's discharge from full charge flight 21m49secs

Airdata UAV - Flight Data Analysis for Drones

And the flight earlier that day when I discharged the first time. A large number of deviations in cell #1:

Airdata UAV - Flight Data Analysis for Drones

 

[stuka75]

Flying lipos below 20% of rated capacity repeatedly, will damage them. Battery temps up to 140f (60c) and beyond are way to hot. The combination is worse. In both cases rated pack capacity will be seriously and permanently compromised. IN a addition, cell one appears to have a significant issue. If the pack is showing any signs of puffing, its toast. Temps in 90'sf and high humidity can be killers if pack is pushed.

 

[Honda_impreza]

Flying lipos below 20% of rated capacity repeatedly, will damage them. Battery temps up to 140f (60c) and beyond are way to hot. The combination is worse. In both cases rated pack capacity will be seriously and permanently compromised. IN a addition, cell one appears to have a significant issue. If the pack is showing any signs of puffing, its toast. Temps in 90'sf and high humidity can be killers if pack is pushed.

It's not my habit to run the batteries below 10% but i was instructed by DJI call centre rep to do so, and to do it twice.

 

[stuka75]

Interesting, consensus on the forums based on experienced lipo users this is not the thing to do. In fact DJI had discontinued recommending it be done. Guess it depends on who you talk to at DJI. That said, if you continue to get significant t warnings via Aiardata after say a routine flight of ten-fifteen minutes and battery usage not beyond 20 30 percent, then the battery is bad. Not worth the risk for flight.

 

[BigAl07]

Interesting, consensus on the forums based on experienced lipo users this is not the thing to do. In fact DJI had discontinued recommending it be done. Guess it depends on who you talk to at DJI. That said, if you continue to get significant t warnings via Aiardata after say a routine flight of ten-fifteen minutes and battery usage not beyond 20 30 percent, then the battery is bad. Not worth the risk for flight.

Our company still runs our "Smart" batteries down to approx 8% on or around the 20th charge cycle. We have roughly 30 batteries we do this with and it's worked perfectly since day 1.

YMMV

 

[stuka75]

"smart batteries" Are they lithium polymer as in our Phantoms? Or Liion like laptops etc.? They are different in charging and behavior.
What do your company batteries power?