How low should I allow the battery to go before I stop flying?

[Steve.M]

I can't find DJI's recommendation in my Air 2S manual. Currently, I stopped flying when the remaining battery level drops to 20% as viewed on the DJI Fly app. Is this a safe time to stop flying or can I go lower?

 

[slup]

If you by "stop flying" mean... have landed & the motors have shut off ... then yes, that's a good level both for not straining you battery too much, having some extra % if the return flight doesn't go as smooth as you thought or if you have to maneuver some due to some reason when going in for the landing. Also, you are percentage wise a bit higher so you don't get surprises like "low battery RTH or auto landings" just when you're trying to line up for landing.

In order to care for your battery & get a long service life out of it, I think it's good to aim for "landed with stopped motors" at 20% ... in that way you rarely will end up below 15% which I think is a minimum level on a regular basis.

 

[old man mavic]

@Steve.M regularly taking the battery to very low levels could shorten the life of the cells ,but what you have to remember is as the cells deplete below 40% their ability to provide enough voltage is diminished as the resistance increases in the cells, i prefer to be coming home and landing around 40% ,if you get home and there is something preventing you from landing straight away ,then having that reserve of battery power gives you some hover time to assess the situation ,because when the battery reaches a certain point the drone will just land lipos have two states they dont like to be in for to long, and they are fully charged, and below around 3.7 volts per cell

 

[Jagerbomb52]

Most of my videos are no longer then 6-7 minutes. I hardly ever go below 60%. When I get home I will discharge them to around 40-45%. Been working for me for over 7 years.

 

[Phantomrain.org]

Many of us take are batteries down to 5 % and have not noticed any effects to the battery on the Air 2 and Air 2S . As long as you have good Visual Line of sight , and have some remote landing spots if needed you can be safe that way also.

Phantomrain.org
Gear to fly in the Rain.

 

[SmilingOgre]

25 to 30% is my MO. I get nervous if I let it go lower.

 

[sduck]

When I get the auto RTH beeping I usually hit cancel, finish up what I'm doing if possible, and then fly back. You don't want to mess around after getting that warning - the emergency auto landing thing can be a mess (don't ask how I know).

 

[zeusfl]

Normally I land at 25-20% of my batteries and push it 15%. Once every 20 cycles I drop it to 5% just hovering to move all the electrolytes.

 

[slup]

...Once every 20 cycles I drop it to 5% just hovering to move all the electrolytes.

When doing this you just put extra strain on your battery, waste charge cycles & effectively shorten the batteries service life by increasing the internal resistance. (And yep ... know that Airdata still have it in their service schedule ... but it's wrong )

The procedure you mimic is coming from the past & the intent was to re-calibrate the BMS chip which at that time didn't was on today's high quality ... the, by the BMS estimated percentage, came out of sync with the actual voltage in the battery ... discharging the battery to 0% & then full charge, it made them sync again. Today this isn't necessary ... the BMS chip we have in the batteries now doesn't go out of sync.

Then ... "move all the electrolytes"

The battery electrolyte is a solution inside batteries. Depending on the type of battery, it can be a liquid or paste-like substance. However, no matter the type of battery, the electrolyte serves the same purpose: it transports positively charged ions between the cathode and anode terminals.

No electrolyte will be moved during use ... & you will not move any by discharging the battery either.

​

 

[zeusfl]

When doing this you just put extra strain on your battery, waste charge cycles & effectively shorten the batteries service life by increasing the internal resistance. (And yep ... know that Airdata still have it in their service schedule ... but it's wrong )

The procedure you mimic is coming from the past & the intent was to re-calibrate the BMS chip which at that time didn't was on today's high quality ... the, by the BMS estimated percentage, came out of sync with the actual voltage in the battery ... discharging the battery to 0% & then full charge, it made them sync again. Today this isn't necessary ... the BMS chip we have in the batteries now doesn't go out of sync.

Then ... "move all the electrolytes"

The battery electrolyte is a solution inside batteries. Depending on the type of battery, it can be a liquid or paste-like substance. However, no matter the type of battery, the electrolyte serves the same purpose: it transports positively charged ions between the cathode and anode terminals.

No electrolyte will be moved during use ... & you will not move any by discharging the battery either.

​

I am old school and still have my old habits sometimes. I know you are right about the new batteries. Still, airdata does alert you to keep maintenance on your batteries in this way. you need a gold account in order to use that feature. I guess they need to update that.

 

[MS Coast]

Many of us take are batteries down to 5 % and have not noticed any effects to the battery on the Air 2 and Air 2S . As long as you have good Visual Line of sight , and have some remote landing spots if needed you can be safe that way also.

For me, 5% is cutting it far too close to allow for possible problems in flight (hawk attack and need to climb) and in the landing area (irate person getting in my face). Maybe it's some residual thing from flying manned airplanes years ago, but the idea of landing with 5% "fuel" reserve horrifies me.

From what I understand, depleting LiPo batters beyond 20 to 25% doesn't show any immediate problems, but rather decreases the life and increases the potential for a failure, like overheating, swelling, and popping out of the aircraft. That fact that the battery hasn't yet had a severe capacity reduction or failed isn't evidence that taking the charge down to 5% isn't doing damage.

Personally, my idea of good flight management is shutting down with no less than 20% and good battery management is shutting down 25 - 30%. And if a low battery RTH was initiated, I'd tell myself that I wasn't paying enough attention to the power levels and put myself in a bind.

 

[SmilingOgre]

From what I understand, depleting LiPo batters beyond 20 to 25% doesn't show any immediate problems, but rather decreases the life and increases the potential for a failure, like overheating, swelling, and popping out of the aircraft.

I haven't tested the Mavic batteries but I have tested batteries like an 18650, 20650, and 21600 and the voltage sag under load becomes substantial below 20 to 30 percent. I don't have all of the DJI specifications to estimate possible damage but both the bird and the battery could be at risk during high demand circumstances.

 

[eran]

When doing this you just put extra strain on your battery, waste charge cycles & effectively shorten the batteries service life by increasing the internal resistance. (And yep ... know that Airdata still have it in their service schedule ... but it's wrong )

The procedure you mimic is coming from the past & the intent was to re-calibrate the BMS chip which at that time didn't was on today's high quality ... the, by the BMS estimated percentage, came out of sync with the actual voltage in the battery ... discharging the battery to 0% & then full charge, it made them sync again. Today this isn't necessary ... the BMS chip we have in the batteries now doesn't go out of sync.

Then ... "move all the electrolytes"

The battery electrolyte is a solution inside batteries. Depending on the type of battery, it can be a liquid or paste-like substance. However, no matter the type of battery, the electrolyte serves the same purpose: it transports positively charged ions between the cathode and anode terminals.

No electrolyte will be moved during use ... & you will not move any by discharging the battery either.

​

Hi Slup!

Our maintenance section and recommendations were reviewed by DJI Services a couple of months back and we continue to work closely with DJI on this.

Please never discharge a battery all the way to 0% as it could indeed harm the battery. DJI still does recommend discharging and charging on a regular basis. Please see one example from the M300 maintenance manual, page 13/14, here: https://dl.djicdn.com/downloads/matrice-300/20200507/M300_RTK_Maintenance_Manual_v1.0_EN.pdf

AirData HD 360 Gold plan and higher can help you track all of this, as well as track DJI specific services for their Enterprise drones (performed by DJI services) please see AirData is Taking Its Drone Fleet Management Platform to the Next Level With the Integration of DJI Maintenance for more info.

I hope this helps!

 

[Dougcjohn]

Agree not suggested to take a LiPo battery to 0 to maybe 5% while under “load”, although taking them down under no load… spinning motors or simply running on ground down to low “percentage” doesn’t equate to hitting minimal voltage or below minimal voltage of the LiPo. Percentage is a FW matrix, not a reliable voltage measurement... and doesn’t represent accurate voltage. A low discharge does help reset or trigger a IC calibration of the percentage not the Gel… not aware of small Mini paks but very prominent in larger platform expensive paks.

The DJI battery IC board & FW prevent both over charge & under charge (excluding a surge under load at low %). Even at 0% (no load) a DJI battery doesn’t measure below the cell’s minimal voltage for a LiPo pack… normally a comfortable ways away from minimal voltage. This can be self tested, land at above 5% and let it run on ground… it won’t run below 0% or possibly below 2-3%, it’ll shutdown. Measure battery and it’s a safe margin above specified minimal voltage.

Damage of LiPo battery isn’t occurring to any degree taking it down into single digit percentage, it’s well within voltage parameters. The greatest damage that accelerates the decay of the LiPo gel is excessive Heat (Excessive high-C discharge & recharge hot gel). Recharging the battery when warm; This increases decay / breakdown of gel and increases IR. If battery feels warm to touch, then gel internally is hot! The swelling of bsttery is breakdown of Gel, unable to hold full charge or battery drops quickly is decay of LiPo Gel chemicals.

DJI smart batteries remove the majority of concern on flight & charging compared to charging standard LiPo’s that charge rates & limits are managed by the Operator.

Avoid charging them when hot, avoid high loads below 18-20%… fly more relaxed returning to LZ. Try to store battery at 30-50% charge, avoid storing or recharge a stored battery at 15%.

Keep in mind, LiPo’s Gel chemical decays reguardless of treatment, how it’s treated can minimize or accelerate that decay. Store on the cool side of temps… a cool basement is better than a hot garage.

I’ve got several TB48 series (48+ batteries) for M600Pro & Inspire 1 that still perform well… using the above practice. Multiple Mavic Pro & Pro 2 batteries, hadn’t experienced a swelled battery. My failures have been TB50 for Inspire 2, mainly just fail to charge due to IC board or charge and then later fail to discharge with normal use. Recharge and next event shows error & non operating occurs with the TB50, but not TB55.

 

[slup]

Hi Slup!

Our maintenance section and recommendations were reviewed by DJI Services a couple of months back and we continue to work closely with DJI on this.

Please never discharge a battery all the way to 0% as it could indeed harm the battery. DJI still does recommend discharging and charging on a regular basis. Please see one example from the M300 maintenance manual, page 13/14, here: https://dl.djicdn.com/downloads/matrice-300/20200507/M300_RTK_Maintenance_Manual_v1.0_EN.pdf

AirData HD 360 Gold plan and higher can help you track all of this, as well as track DJI specific services for their Enterprise drones (performed by DJI services) please see AirData is Taking Its Drone Fleet Management Platform to the Next Level With the Integration of DJI Maintenance for more info.

I hope this helps!

I'm not quite follow you here ...

You attach a maintenance manual from a Matrice that you claim show that DJI supports "Deep discharge cycling" ... but the standard charge/discharge instructions there doesn't recommend any excessive low percentage for the discharge ... below 20% is enough.

And that the battery is recommended to be cycled each 3 month during storage is purely due to that DJI batteries have a BMS chip ... this chip will put a small load on the battery even if the device is off, which risk draining either the whole battery or a cell in the battery to damaging low levels.



In your Airdata Basic Battery Maintenance you state as per below ... the re-initialization you talk about there isn't necessary with today's BMS chip & isn't mentioned in the DJI battery documentation you provided ... they don't go out of sync, doesn't need calibrations or any re-initialization by discharging until the battery can't be turned on anymore.

 

[Squidinc]

I’ve been flying my Air 2 for over a year, and regularly land with circa 10% battery level remaining. However I always ensure my Air 2 is well and truly almost home as an insurance when I’m at 10% or lower.

 

[spamgnome]

Many of us take are batteries down to 5 % and have not noticed any effects to the battery on the Air 2 and Air 2S . As long as you have good Visual Line of sight , and have some remote landing spots if needed you can be safe that way also.

Phantomrain.org
Gear to fly in the Rain.

How do you verify that there have not been any ill effects? Are you looking at airdata, for example?

 

[Phantomrain.org]

How do you verify that there have not been any ill effects? Are you looking at airdata, for example?

No i do not rely on Air Data as not that reliable of a source when it comes to wind and battery .

I keep it simple green is good. If ever I were to get a Red flash I would know
that something has gone astray. Batteries are expensive and If I thought running them down to 5 % was hurting them in any way I would not be to keen on doing it.

Since I record storms I want to stay in the sky as long as possible so that is where I got in the habit of
running my batteries down to 5% with some remote spots for landing if need be.


Phantomrain.org
Gear to fly in the Rain. Land on the Water.

 

[Steve.M]

I want to thank everyone for their replies to my question. Your recommendations go from a low of 5% to a high of 40%. Not a clear answer; however, it does help.
My take on your responses is two fold:
One - Ending my flight at 20% appears to be a safe, and conservative point.
Two - I'm shocked that DJI doesn't address this point in the Air 2S manual!

 

[spamgnome]

No i do not rely on Air Data as not that reliable of a source when it comes to wind and battery .

I keep it simple green is good. If ever I were to get a Red flash I would know
that something has gone astray. Batteries are expensive and If I thought running them down to 5 % was hurting them in any way I would not be to keen on doing it.

Since I record storms I want to stay in the sky as long as possible so that is where I got in the habit of
running my batteries down to 5% with some remote spots for landing if need be.


Phantomrain.org
Gear to fly in the Rain. Land on the Water.

View attachment 142304

Why do you say that AD is not accurate when it comes to batteries? I know from experience that it's been very useful to me to monitor the deviations. These corresponded to several emergency descents that I experienced.