Sounds like you had cells short out.....discharging did not cause that problem......if you don't discharge then to around 10% on a regular basis you will need to deep discharge them every now and then so they will take a full charge......I choose to not charge till 10% if possible....also on the app you can look at the individual cells of the battery.....if one is considerably lower than the rest you have a problem......the battery might show it has a charge but the low cell could short to another cell or drain faster than the others which can cause cause a catastrophic failure if you are in flight.....I just ran one down to 6% and another to 7% yesterday and they charged fine....not a good idea to leave these types of batteries on a charger over night.....if a cell shorts to another while charging it can cause a fire as you almost saw
Deep discharge to 8% destroyed my battery
- Thread starter J.James
- Start date
Sounds like you had cells short out.....discharging did not cause that problem......if you don't discharge then to around 10% on a regular basis you will need to deep discharge them every now and then so they will take a full charge......I choose to not charge till 10% if possible....also on the app you can look at the individual cells of the battery.....if one is considerably lower than the rest you have a problem......the battery might show it has a charge but the low cell could short to another cell or drain faster than the others which can cause cause a catastrophic failure if you are in flight.....I just ran one down to 6% and another to 7% yesterday and they charged fine....not a good idea to leave these types of batteries on a charger over night.....if a cell shorts to another while charging it can cause a fire as you almost saw
Why do you recommend this action?
Why do you 'need' to deep discharge a lithium polymer battery?
What benefit does deep discharging provide?
What cell voltage do you suggest to run down to?
...
Just because you ran your lipos down to 6 and 7% and they charged fine, this does not mean that you haven't done some form of damage to them and that the IR won't rise more quickly. Regularly running a lipo below 20% (~3.75v) will kill it quicker and put your bird in greater risk if you fly longer flights.
From my reading I believe these to be HV 4S lipos with 4.35v per cell. Revolectrix and other manufacturers offer these lipos in the RC sector and they rely on good battery chemistry to obtain this voltage and keep decent capacity (this is why they are light for their size and expensive). If the Phantom likes higher voltage to perform well, imagine how poorly it will perform at 3.5v compared to 4.35v. That is a big step down in maximum rotor speed during the flight. There will be considerable sag in the system once the lipos age, especially at the end of a flight so running 'til the point of near depletion potentially may increase the likelihood of in flight shutdowns/failures. Trying flying back through wind with all this stacked against you!
Please read my above posts.
3D helis are dangerous, expensive toys you fly near yourself very aggressively. No one in their right mind plays around with killing their expensive lipos and puts their heli or themselves (or others) at risk for the sake of slight extra flying time.
If I get 15 safe minutes of flight with my Phantom (which arrives today) that is fine. I will just buy more batteries as I don't with to chew threw $205 lipos due to incorrect battery advice.
Why do you 'need' to deep discharge a lithium polymer battery?
What benefit does deep discharging provide?
What cell voltage do you suggest to run down to?
...
Just because you ran your lipos down to 6 and 7% and they charged fine, this does not mean that you haven't done some form of damage to them and that the IR won't rise more quickly. Regularly running a lipo below 20% (~3.75v) will kill it quicker and put your bird in greater risk if you fly longer flights.
From my reading I believe these to be HV 4S lipos with 4.35v per cell. Revolectrix and other manufacturers offer these lipos in the RC sector and they rely on good battery chemistry to obtain this voltage and keep decent capacity (this is why they are light for their size and expensive). If the Phantom likes higher voltage to perform well, imagine how poorly it will perform at 3.5v compared to 4.35v. That is a big step down in maximum rotor speed during the flight. There will be considerable sag in the system once the lipos age, especially at the end of a flight so running 'til the point of near depletion potentially may increase the likelihood of in flight shutdowns/failures. Trying flying back through wind with all this stacked against you!
Please read my above posts.
3D helis are dangerous, expensive toys you fly near yourself very aggressively. No one in their right mind plays around with killing their expensive lipos and puts their heli or themselves (or others) at risk for the sake of slight extra flying time.
If I get 15 safe minutes of flight with my Phantom (which arrives today) that is fine. I will just buy more batteries as I don't with to chew threw $205 lipos due to incorrect battery advice.
During the automatic discharge to 50% that the P3 battery does after a set number of days, does it get hot? I ask this because mine are often in my hard shell backpack for several days and if they discharge and get hot, it could be a problem.
Hello there,Like anything it's repetition.
Aim for say 3.75v resting per cell for a happy battery. We all have flights where sometimes you'll out of the blue go under 3.70v but make this the exception and immediately charge back to storage voltage (3.85v) if this happens.
Lipos should last 100 flights; even 200 if you are careful and the lipo was a decent C rating and low IR to start with. Poor care will result in quicker degradation though a new lipo will be fine for say 25 flights even with total abuse. After this performance will reduce progressively (maybe dramatically if it's constantly run dry) so care from the start will mean you'll get more value for your money and have less risk in regards to charging, drifting cells, dropped cells, puffing, premature sag etc.
3.5v per cell is bad news IMHO. No one in the heli game takes their lipos that low. It's the 20% rule.
I even work by 20% on my iPads etc...I have a gen 1 iPad that was used to death and the thing still has amazing battery life...even though I basically can't use it anymore for anything other than movies or eBooks.)
Does anyone know the C rating of the P3 4S lipo?. I doubt it has one but I imagine it's pretty low.
Say I saw that you were asking about the c rating and ratings on lipo batteries and also that you have many batteries for your multiple craft hobby or 3D helloes and thought you would find this helpful it is well done in my opinion .. hope it is a help to you and all the pilots here at Phantom Pilots…!!! ;-)
Link:
Lots of conflicting info in this thread and other battery threads. I'm of the opinion that what's stated in the manual is probably best.
We often read about crashes and unexpected landings and "drops from the sky." They often seem to be unexplained. It seems often that the drop is from a craft flown by an experienced pilot using a battery which isn't exactly new. The battery reads it has a good charge. Often the reading will suddenly drop from a relatively strong percentage to a low percentage. And then the craft comes down. Why does this happen?
I read a post a while back in the Vision+ forum by a member called DBS MODS and he said that the people who say you shouldn't discharge low are wrong. He says they're wrong because these are intelligent batteries. He says the manufacturer knows what is best, and the software is written to protect a healthy battery. He does battery mods and holds world records for flight duration, so he seems to know what he's talking about. He said the smart battery has software in it which will automatically shut down the battery when it reaches 10.5 volts. That equates to 3500 volts per cell (again, he is referring to P2V batteries).
I am looking at the most recent (11/3/15) P3 Adv manual and it says that the built-in discharge protection in the Go app will not allow the discharge to go below 12 volts. That's 3000 mv per cell. That's pretty low.
See page 18, #8 here:
https://dl.djicdn.com/downloads/phantom_3/en/Phantom_3_Advanced_User_Manual__V1.6.pdf
Another DJI link states that you should perform a deep discharge on your P3 Adv/Pro battery every 20 charge cycles, and you should discharge it until it is 8% or the battery won't turn on.
http://download.dji-innovations.com...igent_Flight_Battery_Safety_Guidelines_en.pdf
I don't have a P3, but I do have a Vision and I want my batteries to last a while. I have broken them in carefully using 10 & 10. I decided to follow my manual's advice and DBS MODS advice. And by the way, the Vision manual does not say to discharge to 8% as many people have repeatedly claimed all over this site. The Vision manual says to discharge BELOW 8%.
So I deep discharged my battery for the first time. It had 21 cycles as reported in the asst app so it was time to do the deep discharge.
After a while, the discharger shut down automatically as expected. I then plugged the battery into my craft and into the asst software, turned the battery on and it read:
Voltage: 10505 mv
Percentage of Charge 3%
Cell 1: 3528
Cell 2: 3490
Cell 3: 3477
The numbers were dropping as the battery powered the craft, even in its idle state. I turned the battery off.
Granted I would prefer to have better balance than that. I thought deep discharging would sort of force the cells to balance. Guess not.
I then charged the battery. It charged normally.
I then placed it in the aircraft, turned it on, brought up the asst software, and it reads:
Voltage: 12588 mv
Percentage of charge: 100%
Cell 1: 4198
Cell 2: 4192
Cell 3: 4193
Percentage of Life: 93%
Design Capacity: 5200 mAh
Full Capacity: 5377 mAh
Current Capacity: 5381 mAh
...
I think one of the best posts on this subject is this one from another thread:
The key phrase is in the first sentence: "periodic calibration." Maybe in your opinion a deep discharge is not wise. Maybe in your opinion the instructions on the DJI site are wrong and you are inclined to ignore them. In that case, you wouldn't do a deep discharge to improve the health of the battery. You would do a deep discharge so that you don't have a false reading in your app while flying.
We often read about crashes and unexpected landings and "drops from the sky." They often seem to be unexplained. It seems often that the drop is from a craft flown by an experienced pilot using a battery which isn't exactly new. The battery reads it has a good charge. Often the reading will suddenly drop from a relatively strong percentage to a low percentage. And then the craft comes down. Why does this happen?
I read a post a while back in the Vision+ forum by a member called DBS MODS and he said that the people who say you shouldn't discharge low are wrong. He says they're wrong because these are intelligent batteries. He says the manufacturer knows what is best, and the software is written to protect a healthy battery. He does battery mods and holds world records for flight duration, so he seems to know what he's talking about. He said the smart battery has software in it which will automatically shut down the battery when it reaches 10.5 volts. That equates to 3500 volts per cell (again, he is referring to P2V batteries).
I am looking at the most recent (11/3/15) P3 Adv manual and it says that the built-in discharge protection in the Go app will not allow the discharge to go below 12 volts. That's 3000 mv per cell. That's pretty low.
See page 18, #8 here:
https://dl.djicdn.com/downloads/phantom_3/en/Phantom_3_Advanced_User_Manual__V1.6.pdf
Another DJI link states that you should perform a deep discharge on your P3 Adv/Pro battery every 20 charge cycles, and you should discharge it until it is 8% or the battery won't turn on.
http://download.dji-innovations.com...igent_Flight_Battery_Safety_Guidelines_en.pdf
I don't have a P3, but I do have a Vision and I want my batteries to last a while. I have broken them in carefully using 10 & 10. I decided to follow my manual's advice and DBS MODS advice. And by the way, the Vision manual does not say to discharge to 8% as many people have repeatedly claimed all over this site. The Vision manual says to discharge BELOW 8%.
So I deep discharged my battery for the first time. It had 21 cycles as reported in the asst app so it was time to do the deep discharge.
After a while, the discharger shut down automatically as expected. I then plugged the battery into my craft and into the asst software, turned the battery on and it read:
Voltage: 10505 mv
Percentage of Charge 3%
Cell 1: 3528
Cell 2: 3490
Cell 3: 3477
The numbers were dropping as the battery powered the craft, even in its idle state. I turned the battery off.
Granted I would prefer to have better balance than that. I thought deep discharging would sort of force the cells to balance. Guess not.
I then charged the battery. It charged normally.
I then placed it in the aircraft, turned it on, brought up the asst software, and it reads:
Voltage: 12588 mv
Percentage of charge: 100%
Cell 1: 4198
Cell 2: 4192
Cell 3: 4193
Percentage of Life: 93%
Design Capacity: 5200 mAh
Full Capacity: 5377 mAh
Current Capacity: 5381 mAh
...
I think one of the best posts on this subject is this one from another thread:
The key phrase is in the first sentence: "periodic calibration." Maybe in your opinion a deep discharge is not wise. Maybe in your opinion the instructions on the DJI site are wrong and you are inclined to ignore them. In that case, you wouldn't do a deep discharge to improve the health of the battery. You would do a deep discharge so that you don't have a false reading in your app while flying.
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What you're basically advising is to ignore the science of lithium polymer batteries and the knowledge a whole industry of RC manufacturers and enthusiasts has garnered over a number of years and go with some bloke that does mods.
The P3 lipos are HV lipos; that is 4.35v per cell when charged.
If you run them down to 3.5v per cell resting, you are seriously discharging them and the cells will be damaged over time. Revolectrix (a manufacturer of good lipo batteries) does not advise running 4.35v lipos down to the same level as 4.2v lipos.
I have used regular 4.2v per cell (charged) lipos for 3 1/2 years; I've got 3 years of life out of cheap lipos that I've tortured with 3D helis because I look after them. That is never less than 80% discharge.
No one in the RC industry advised to run your 4.2v lipos to 3.5v. That is a sure fire way of destroying lipos in short order and getting high IR quickly.
The reason DJI recommends full discharging and charging is because these 'intelligent' batteries have a very 'unintelligent' charger that does not balance charge the individual cells. So it's a brute force, kludgey work around.
A proper charger like an iCharger or PowerLab charges the lipo and then balanced charged individual cells to get a perfect charge every time. It also measures IR so you know what condition individual cells are in.
For example, two of those 3 yo lipos I mentioned recently dropped one cell's voltage slightly.
If we went with your advice, I may have tried a max discharge and tried to get them balanced again which may have worked (at least temporarily).
In actual fact, the IR for those single cells which dropped (6S lipos) was far higher than the other cells (~4ohms vs ~18). This would have been quite suicidal to continue using them and likely resulted in a fire during flight or a crash due to a cell totally failing. I know what dropped lipo cells due during flight or during discharge (fire).
On two occasions I have found that if I charge a P3 lipo and for whatever reason cannot fly it (I run out of time), these 'intelligent' lipos whilst stating I have a full battery a few days later have in fact self discharged (I have them set at 10 days). I know this because I click the button to check voltage and think great, still 4 bars of charge, I can fly them.
But as I know better, I then put them on the charger to confirm and seconds later they have started charging like they have 20% in them.
It's only happened twice but I gave me pause.
So now I do this every time I fly; even if a lipo has only sat charged overnight (it takes a few hours to charge a few lipos so naturally I do it the night before a days flying). If they don't start charging, they are good to go.
IMHO, some people that have had in flight failures have had this very same thing happen but they unfortunately haven't checked via the charger prior to flying and have found that their lipos cry uncle during a long flight (they go too far away, don't realise the lipo is already down to say 40% and can't fly back in time).
Anyway, this is JMHO and dovetails into all the knowledge I've gathered from flying RC helis.
The 'health' component of the app must read cycles or IR in some way and gives you 'something' at least to qualify the health of the lipo.
For peace of mind, I personally always land at 30% discharge which I deem is sufficiently depleted (~3.65v under load).
Even just hovering around filiming, I have found that the P3 lipos get very hot in flight and IMHO, the P3 would be better suited to a 6S setup (6 cell rather than 4 cell). The inspire must be pretty hard on lipos.
The P3 lipos are HV lipos; that is 4.35v per cell when charged.
If you run them down to 3.5v per cell resting, you are seriously discharging them and the cells will be damaged over time. Revolectrix (a manufacturer of good lipo batteries) does not advise running 4.35v lipos down to the same level as 4.2v lipos.
I have used regular 4.2v per cell (charged) lipos for 3 1/2 years; I've got 3 years of life out of cheap lipos that I've tortured with 3D helis because I look after them. That is never less than 80% discharge.
No one in the RC industry advised to run your 4.2v lipos to 3.5v. That is a sure fire way of destroying lipos in short order and getting high IR quickly.
The reason DJI recommends full discharging and charging is because these 'intelligent' batteries have a very 'unintelligent' charger that does not balance charge the individual cells. So it's a brute force, kludgey work around.
A proper charger like an iCharger or PowerLab charges the lipo and then balanced charged individual cells to get a perfect charge every time. It also measures IR so you know what condition individual cells are in.
For example, two of those 3 yo lipos I mentioned recently dropped one cell's voltage slightly.
If we went with your advice, I may have tried a max discharge and tried to get them balanced again which may have worked (at least temporarily).
In actual fact, the IR for those single cells which dropped (6S lipos) was far higher than the other cells (~4ohms vs ~18). This would have been quite suicidal to continue using them and likely resulted in a fire during flight or a crash due to a cell totally failing. I know what dropped lipo cells due during flight or during discharge (fire).
On two occasions I have found that if I charge a P3 lipo and for whatever reason cannot fly it (I run out of time), these 'intelligent' lipos whilst stating I have a full battery a few days later have in fact self discharged (I have them set at 10 days). I know this because I click the button to check voltage and think great, still 4 bars of charge, I can fly them.
But as I know better, I then put them on the charger to confirm and seconds later they have started charging like they have 20% in them.
It's only happened twice but I gave me pause.
So now I do this every time I fly; even if a lipo has only sat charged overnight (it takes a few hours to charge a few lipos so naturally I do it the night before a days flying). If they don't start charging, they are good to go.
IMHO, some people that have had in flight failures have had this very same thing happen but they unfortunately haven't checked via the charger prior to flying and have found that their lipos cry uncle during a long flight (they go too far away, don't realise the lipo is already down to say 40% and can't fly back in time).
Anyway, this is JMHO and dovetails into all the knowledge I've gathered from flying RC helis.
The 'health' component of the app must read cycles or IR in some way and gives you 'something' at least to qualify the health of the lipo.
For peace of mind, I personally always land at 30% discharge which I deem is sufficiently depleted (~3.65v under load).
Even just hovering around filiming, I have found that the P3 lipos get very hot in flight and IMHO, the P3 would be better suited to a 6S setup (6 cell rather than 4 cell). The inspire must be pretty hard on lipos.
I would agree with that statement-- in fact- frequent flying batteries to low voltage may indeed damage the battery and reduce it's life. The important thing to watch is the cell imbalance-- check it on every battery frequently to make sure there are no cells that vary in voltage over about .06 to .10 with no load. Any differing voltage from the others in will be a sure sign of future or present problems for that battery. If a battery cant be deep cycled and the voltage readings normalize, then I will pull it out of service.
That battery is the lifeline -- don't take chances with it.
This post IMHO is based on my experience with lipos flying RC planes and my quadcopters. Cheers
I followed the recommended discharge to 8% every 20 flights carefully with my P2 batteries and was frankly never happy with them. The longest any ever lasted was 70 flights but most of them only lasted 50. I had 10 of them in all.
With the P3, I have 4 and they have 44, 44, 43 and 34 flights on them without ever doing a deep discharge. I occasionally fly down to just below 20% but usually more like 25 to 30%. They are set to discharge in 2 days and I typically charge within 12 hours of going flying. All of them look to be healthy based on the data at healthydrones. So I am going to stick with this method for these 4 batteries - I hope they last me until the Phantom 4.
With the P3, I have 4 and they have 44, 44, 43 and 34 flights on them without ever doing a deep discharge. I occasionally fly down to just below 20% but usually more like 25 to 30%. They are set to discharge in 2 days and I typically charge within 12 hours of going flying. All of them look to be healthy based on the data at healthydrones. So I am going to stick with this method for these 4 batteries - I hope they last me until the Phantom 4.
N017RW
Premium Pilot
N017RW
Premium Pilot
Not to be knit-picky but the recommended proceedure is 20 'cycles' not flights. These cycles are not equal to # of flights or charging sessions. It appears to be calculated based on the amount of discharge/charge rather than events.
There is no recommendation to discharge a P2 battery to 8% every 20 flights. Could that be the problem? What the manual says is to perform a deep discharge BELOW 8% every 20 discharges.
What I'm suggesting is maybe it's best to follow the recommendation of the manufacturer, who specifically states "This power cycling procedure will optimize battery life."
...
But the major point, which might have been lost due to the length of my post (sorry), is if in your opinion DJI is wrong, and you believe a deep discharge doesn't optimize the useful life of your battery, then you would NOT perform a deep discharge for the health of the battery (three figures $$$) - you would perform a deep discharge for the health of the AIRCRAFT (four figures $$$$).
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To properly discharge the battery you should run the phantom to 25% and then let it cool down and remove the props . Then only turn the battery on and let it run down under minimal load. What will damage the cells is hovering your phantom all the way down to 8% this is very bad. Always let the battery cool down and then run the battery down with the phantom on the ground with the props off.
Not according to DJI. From the Phantom 3 Users Manual:
"DJI Intelligent Flight Battery Functions: Balanced Charging automatically balances the voltage of each battery cell when charging."
And this is quite evident when I see that all 3 of my batteries, after full charge, typically have cell voltages within 0.01 volts of each other. Brute force charging wouldn't yield such close cell voltages.
I seriously wish there was a way to use my high end balancing lipo charger on the "smart" Phantom battery. This is the first time I've used lipos that I feel like I have little control over. Of course, that's the way I feel about the Phantom, too. I can't swap out the ESC, upgrade/swap out the Rx, or tinker with it at all. Feels odd, I'm so used to being in "control" of my R/C craft. I guess it's kind of like an old TV set from the 70's you could actually work on vs today's throw away sets when they break. Or a car engine. Worked on one of those lately?
Sorry, someone get us back on batteries.
Sorry, someone get us back on batteries.
By looking at the picture posted, I would say the IC has an internal fault and is the cause of the heat.
Unfortunately the numbers of the IC aren't clear, but I'd replace the IC anyway and try charging the battery again.
Unfortunately the numbers of the IC aren't clear, but I'd replace the IC anyway and try charging the battery again.
I just tested the battery pack cutoff voltage.
current at approx 5.5amps
The battery pack switches itself off at 12.2v (3.05v/cell).
For years I've been told that 3v is the minimum voltage per cell with LiPo's, so I would say 8% should be fine (very close to 3.8v)
current at approx 5.5amps
The battery pack switches itself off at 12.2v (3.05v/cell).
For years I've been told that 3v is the minimum voltage per cell with LiPo's, so I would say 8% should be fine (very close to 3.8v)
