"...if that is the only option" is the whole title.

Many of us have been in the situation where there is no possibility to recharge batteries - few days in the wilderness for instance.
Then a magnificent motive pops up and you have your drone with you just for such cases. As batteries have self discharging algorithm after few days they were let's say only at 70%.
This often happen to me as I have always my drone in the car.
Will you fly?

No I would not fly.  

Hi, thanks for reaching DJI Forum. We do appreciate bringing this query to us, but we do suggest to keep your batteries fully charged before using it. Another good thing about charging constantly is to keep the batteries in a healthy state and to ensure the longevity of the batteries maximum performance.

Maybe you should get yourself a battery car charger.

I believe my batteries discharge after 10 days and I think you  can set that.

Yes, set them to begin the auto discharge, for the maximum amount of time, allowed.

Gives you a wee bit more leeway.

I would fly at 70%, but Only keeping the aircraft low to the terraferma and close up... no heroic stunts. Ha
Get you short incredible video, or delightful pics taken, and land.


RedHotPoker

To me, it depends.   
Battery at 50% and I expect to be up for 5 minutes, I'm getting the shot.  
Battery at 50% and I expect to be up for 10 minutes, nope, staying on the ground.

Nope i wouldnt fly. I keep my batteries topped up always before flight and in that situation i would have ensured i have a means to recharge them if needed

OK thanks. That is my opinion too. If the batteries are in good condition I think that at 70% would be no problem flying a few min. Especially if I know that I fully charged it a few days before.
The car charger is OK yes, but sometimes somebody goes to the mountains or other location reachable only by walk. The charger is useless there.
I think 70% in healthy batteries is good enough for a few min. flight, without drain them under 30%.  
.

As long as the battery has been at 100% at some point in the last 24 hours then I will fly at any % where it doesn't refuse to fly - from experience I know it wont take off at 7%, I might extend that to 48 hours if it was for a very good reason.  I suggest you never extend to longer than the self discharge period, although you can extend the self discharge by pressing the button.

For me, my car charger solves the problem, although it quite often only charges to maybe 70% before I fly again in which case I apply the above rule.

andy10 Posted at 2018-7-26 14:22
OK thanks. That is my opinion too. If the batteries are in good condition I think that at 70% would be no problem flying a few min. Especially if I know that I fully charged it a few days before.
The car charger is OK yes, but sometimes somebody goes to the mountains or other location reachable only by walk. The charger is useless there.
I think 70% in healthy batteries is good enough for a few min. flight, without drain them under 30%.  

OK thanks. That is my opinion too. If the batteries are in good condition I think that at 70% would be no problem flying a few min.  ...
I think 70% in healthy batteries is good enough for a few min. flight, without drain them under 30%.  
You might think that but it isn't right.
The problem is that the % indicator is only accurate with a fully charged battery.
A partially discharged battery % indication will be false.
Forums are full of accounts of people that lost their drones by doing wxactly what you are suggesting.
Their recorded flight data shows the voltage is low and falls much faster than a fully charged battery despite a seemingly good % indication at the start.
You might get away with it in some situations .. and you might not.
Launching with a partially discharged battery is asking for trouble.


you are looking at a % indication

Yes, but nature calls, you know what that’s like...

It’s similar of an emergency situation, Damned if you do and peaved off, that you missed the awesome opportunity, if not.

Put a kite string on it. Hahaha


RedHotPoker

Flirting with disaster.  As Labroides says, it has stung many pilots.

ALABAMA Posted at 2018-7-26 15:16
Flirting with disaster.  As Labroides says, it has stung many pilots.

We only hear about the failures.

Minuscular numbers considering the tens of thousands of drones in the air, twenty four hours a day, yes Um yeah, that’s all around the spinning globe.


I agree that it’s not the safest, wisest, prudent practice, to perform drone flights on a depleted flight pack.

I charge, or top up, my intelligent flight battery’s. Yeah, & then go flying... playing safe is mandatory.


RedHotPoker

Well I'm guessing its better to fly with a full battery, but...  If I'm out on a commercial shoot, I'm not going to fly for 30 minutes every time I launch.  With pre-planning it only takes a few minutes to get the shot that is needed.  So what am I supposed to do, fly around for 20 minutes to run the battery down?  I really would like a reliable answer from DJI on this.   Fly for a few minutes and then replace a 70 percent battery,  seems extreme.  j

djiuser_hRZzv67dLdhW Posted at 2018-7-26 20:01
Well I'm guessing its better to fly with a full battery, but...  If I'm out on a commercial shoot, I'm not going to fly for 30 minutes every time I launch.  With pre-planning it only takes a few minutes to get the shot that is needed.  So what am I supposed to do, fly around for 20 minutes to run the battery down?  I really would like a reliable answer from DJI on this.   Fly for a few minutes and then replace a 70 percent battery,  seems extreme.  j

For what it is worth, my regime is to fly a section when I am shooting, come back, change to a fresh battery, then go out again on a fully charged battery. There is no need to fly around draining the battery, it has a self-discharge feature built into it, just let it do its job. Next time you go out, charge all your batteries the night before.

djiuser_hRZzv67dLdhW Posted at 2018-7-26 20:01
Well I'm guessing its better to fly with a full battery, but...  If I'm out on a commercial shoot, I'm not going to fly for 30 minutes every time I launch.  With pre-planning it only takes a few minutes to get the shot that is needed.  So what am I supposed to do, fly around for 20 minutes to run the battery down?  I really would like a reliable answer from DJI on this.   Fly for a few minutes and then replace a 70 percent battery,  seems extreme.  j

I really would like a reliable answer from DJI on this.
You won't get an answer here from DJI, but they do tell you in the manual to always fly with a fully charged battery.
Fly for a few minutes and then replace a 70 percent battery,  seems extreme.
Replacing a 100% Phantom because you flew with a partially discharged battery and reached critical low voltage much quicker than you imagined is a bit extreme.

Your % battery indication is only accurate when you start with a fully charged battery.
If you've just flown down to 70% and launch again soon after, that's fine.
But if you leave the battery for a week and then go to fly with it, you are asking for trouble.

As an example, I needed a quick shot at one location, the next location was 15 miles across the valley.  45 minutes later, ready for the next shot.  Seems like it should be unnecessary to swap out a battery that has only been used for a few minutes.  j

Yep, I fly all the time with batteries not fully charged. I've maybe done 200-300 flights with semi charged batteries.

I have and would, if the batteries are over 50% charged.  If you know your drone and the battery characteristics you will get a feel for their usage rate based on your flight dynamics at the time...  I know that I can get 18 to 20 safe minutes flying my P4 from a fully charged battery (98% and up)…  If I bring my bird back after say 5 minutes because maybe the weather was getting bad and put it away at say 70 to 75% charge, I will still have at least 10 safe minutes of flying the next time I put it in the air.  Enough time for some last minute unplanned shots or video.  
Plus I always bring my batteries to 20% or just under before I recharge them.  I have 4 batteries that have over 125 charges on them..  Each once still shows more than 90% life left.
If you have your smart RTH turned on, it will still work whether you start your flight at 99% or 65%, you'll just have less flight time on the 65%   The % reading is based on Voltage of the battery and the smart batteries circuitry supply that info to the controller and to the screen.  in MY experience, you will still get VERY close to the same flight time total whether you use up most of the power on one flight or you break them up in 3 or 4 shorter ones on the same charge.

Here's some food for thought.  Choose a few of these threads at random and read through them.  

https://forum.dji.com/forum.php? ... 2&page=1#pid1352321

Oldmaninwva Posted at 2018-7-27 00:21
I have and would, if the batteries are over 50% charged.  If you know your drone and the battery characteristics you will get a feel for their usage rate based on your flight dynamics at the time...  I know that I can get 18 to 20 safe minutes flying my P4 from a fully charged battery (98% and up)…  If I bring my bird back after say 5 minutes because maybe the weather was getting bad and put it away at say 70 to 75% charge, I will still have at least 10 safe minutes of flying the next time I put it in the air.  Enough time for some last minute unplanned shots or video.  
Plus I always bring my batteries to 20% or just under before I recharge them.  I have 4 batteries that have over 125 charges on them..  Each once still shows more than 90% life left.
If you have your smart RTH turned on, it will still work whether you start your flight at 99% or 65%, you'll just have less flight time on the 65%   The % reading is based on Voltage of the battery and the smart batteries circuitry supply that info to the controller and to the screen.  in MY experience, you will still get VERY close to the same flight time total whether you use up most of the power on one flight or you break them up in 3 or 4 shorter ones on the same charge.

I always bring my batteries to 20% or just under before I recharge them.
Why?   There's absolutely no need to run batteries down before recharging.
The smart circuitry handles battery management for you.


If you have your smart RTH turned on, it will still work whether you start your flight at 99% or 65%, you'll just have less flight time on the 65%   The % reading is based on Voltage of the battery and the smart batteries circuitry supply that info to the controller and to the screen.
Except that the percentage indication is going to give a false reading if you start with a battery that's been sitting around discharging.
The voltage is what matters, not the % and the voltage can suddenly drop with a partially discharged battery.

I've noticed that the remaining time indication is pretty accurate, even with a battery that's low on charge. Not a week old, but maybe a battery I flew with less than 24 hours ago. It's not like you put in a battery that is 50% charged and the indicator in Go 4 says it's fully charged. It doesn't work like that. It goes by cell voltage.

Nope, because the risk isn't worth the reward.

Mark Weiss Posted at 2018-7-27 07:05
I've noticed that the remaining time indication is pretty accurate, even with a battery that's low on charge. Not a week old, but maybe a battery I flew with less than 24 hours ago. It's not like you put in a battery that is 50% charged and the indicator in Go 4 says it's fully charged. It doesn't work like that. It goes by cell voltage.

But if you put a battery in that's been sitting around for a week or more, although it says it's at 50%, it's not and within a minute it could drop to critical low voltage levels.

I can't make it any clearer.
Don't launch with a battery that's been sitting around discharging for a while.
The percentage indication will give you a false sense of the charge level.

For anyone thinking of taking a chance, read some accounts from the link in post #21.

Labroides Posted at 2018-7-27 08:43
But if you put a battery in that's been sitting around for a week or more, although it says it's at 50%, it's not and within a minute it could drop to critical low voltage levels.

I can't make it any clearer.

Lab,  Thank you

As you know I've been pushing that exact point over many different threads.

Partially charged batteries are completely unreliable.  A reported 50% battery in DJI GO 4 in the air, will most likely show cell voltages in the 3.6vdc range.

3.6vdc per cell is 20% battery or less............CHECK your battery voltages if you insist on flying a partially charged battery, and LAND if your cell voltages go below 3.7vdc.........if over water, and your quad hit critical low voltage, and your % reads 45%.......it doesn't matter any longer, because it will autoland in the drink!

There are many threads on this subject in P4/Mavic/Inspire take your pick.......

Randy

My experience is that the percentage remaining is totally unreliable if it has been self-discharging.
If it is above 50% due to having been flown recently, I might risk a short flight. Note I said risk. It is risky.
If you are going into the bush away from any chargers for a while, be sure and set each battery self-discharge function to 10 days before leaving home. Have to do this for each battery.
Get a car charger.
Get insurance too.

Here's just one example of dozens:

Hey folks! Somewhat recent to the drone hobby, but really enjoying it! Right up until tonight at least.

I was flying my Phantom 3 Standard just out the front of my house, sitting at around 11 meters high. I was in P-GPS mode, 71% battery (I double tapped it into place, just to be sure), fully calibrated, and am in the beginner mode that won't let me switch out of P-GPS. Everything was totally fine, and flying as you'd expect!

Out of nowhere, all the lights on my lovely new drone all begin flashing red; and it just drops out of the sky like a tonne of bricks. Bang! Straight into the pavement - the gimbal comes flying off, and the drone suffers a little damage.

https://phantompilots.com/thread ... -of-sky-help.92881/

Labroides Posted at 2018-7-27 05:33
I always bring my batteries to 20% or just under before I recharge them.
Why?   There's absolutely no need to run batteries down before recharging.
The smart circuitry handles battery management for you.

It is best to let the batteries run down to about 5% before charging them. NOT an in flight discharge, but a table discharge. Also, let the batteries totally cool down before charging them- this is what I have done with my P4 batteries and they are 2 years old with a 80% battery level.

Has anyone mentioned a solar charger?

ATJ Posted at 2018-7-27 14:37
It is best to let the batteries run down to about 5% before charging them. NOT an in flight discharge, but a table discharge. Also, let the batteries totally cool down before charging them- this is what I have done with my P4 batteries and they are 2 years old with a 80% battery level.

Has anyone mentioned a solar charger?

It is best to let the batteries run down to about 5% before charging them.
That's nonsense.
You can recharge from any level of discharge and it makes no difference.

Buy a 12v car charger.  It works for me !

ATJ Posted at 2018-7-27 14:37
It is best to let the batteries run down to about 5% before charging them. NOT an in flight discharge, but a table discharge. Also, let the batteries totally cool down before charging them- this is what I have done with my P4 batteries and they are 2 years old with a 80% battery level.

Has anyone mentioned a solar charger?

If we were talking about NiCAD or NiMH batteries you might have a point.   However LiOn or LiPo batteries do not like to be discharged too low on a regular basis.  If however that is what you are doing and you get satisfactory life then more power to you.  I tend to err on the other side of the no-no practice as I like to keep mine at 100% charge in case I need them.  I know that will shorten their lifespan a little, but to me it is worth it.

Labroides Posted at 2018-7-27 15:51
It is best to let the batteries run down to about 5% before charging them.
That's nonsense.
You can recharge from any level of discharge and it makes no difference.

Don't be fooled by Labroides people Lithium Batteries are prone to a memory as well (especially when they are hot).  Keep charging them at a 50% discharge and eventually you'll find out for yourself. In using Li ion and Li poly for years I have found this to be, VERY MUCH, the truth. You can lead a horse to water.

ATJ Posted at 2018-7-28 02:57
Don't be fooled by Labroides people Lithium Batteries are prone to a memory as well (especially when they are hot).  Keep charging them at a 50% discharge and eventually you'll find out for yourself. In using Li ion and Li poly for years I have found this to be, VERY MUCH, the truth. You can lead a horse to water.

Interesting that no-one else has discovered your secret science.
It's easy to make a claim but can you back it up with supporting evidence?

Labroides Posted at 2018-7-28 03:51
Interesting that no-one else has discovered your secret science.

Experience is the best teacher Captain. I've been using LiPo and LiIon for well over 10 years with my RC Helicopters.

ATJ Posted at 2018-7-28 05:12
Experience is the best teacher Captain. I've been using LiPo and LiIon for well over 10 years with my RC Helicopters.

How long you've used old batteries for in the past is irrelevant.
What's being discussed here is DJI's smart battery technology that's only been around for the last few years.

Labroides Posted at 2018-7-28 05:16
How long you've used old batteries for in the past is irrelevant.
What's being discussed here is DJI's smart battery technology that's only been around for the last few years.

Smart Battery Technology only allows you to fly your Quadcopter at full power until the batteries are almost drained. Smart Technology is in the electronics paired with the battery NOT the battery itself. The batteries are still using the same lithium formula and can still aquire a memory.

ATJ Posted at 2018-7-28 02:57
Don't be fooled by Labroides people Lithium Batteries are prone to a memory as well (especially when they are hot).  Keep charging them at a 50% discharge and eventually you'll find out for yourself. In using Li ion and Li poly for years I have found this to be, VERY MUCH, the truth. You can lead a horse to water.

ALL batterys suffer usage .. and the term 'Memory' is a term that got abused and became accepted fact instead of reality ... Batterys do not actually get a memory as some claim ... NiCd days - this was a constant argument ... what actually happened was repeated partial discharge, it was nothing to do with charging, caused a chemical and physical limitation to be created that needed full cycling to break. LiPo's are resistant to this phenomena.

LiPo's as with ALL batterys have Internal Resistance. This increases with cycles of use until eventually the battery cannot deliver the power asked of it ... temperature goes up ... it swells etc.

Power demand from a battery is not just Volts ... its actually WATTS. That is Volts x Amps. Internal resistance has a direct effect on that by resisting power output and causing voltage drop. That voltage drop then causes the watts demand to ask for compensating amps.  That in turn is resisted and the whole becomes a catch 22 circle.

Leaving LiPo's fully charged causes a chemical action that increases Internal resistance by physical degradation of cell make-up. Simple fact.
Discharging a LiPo cell past 2.8V causes physical damage. This is why the max 3.0V figure has been established. Due to voltage drop in use .. this is then revised to 3.3V in use.

OK - lets get onto this % item.

First it is NOT the Battery circuit board OR the Flight Controller that decides the fate of your AC if battery goes down .... in fact its the ESC's ... The Flight Controller is acting based on your settings programmed in. Critical - it lands ... etc.

Brushless ESC's have what is called LVC ... Low Voltage Cutoff. In the early days - all batterys were treated similarly by ESC and % was based on starting voltage of battery. So even though you may have user set the ESC to 3.3V LVC ... if the battery was partially used - that 3.3V was false as the % of starting battery would be less ....

Example :

Full 4S LiHV is 17.4V
3.3v x 4 = 13.2V
This means that LVC of 3.3v per cell = 75.9% of full charged pack.

Now lets say the pack is partially used and now sits 15.0V as starting voltage.
75.9% of 15.0V = 11.39V or 2.85V per cell ....

Your user setting of 3.3V is no longer valid ... its purely a % figure relationship of full battery.

Your ESC will not carry on till it hits 2.85V per cell before it cuts out.

Now that calculation is as per older ESC in normal RC models. Later ESC's replaced the % with actual settable VOLTAGE figure ... so 3.3V was set regardless of starting voltage. A giant leap forward !!

Now lets move to the DJI ... lets assume the old method of % is used for LVC in the ESC's ... more than likely actually as its not really necessary for ESC to have LVC as the Flight Controller reading all info should default to land etc.
So now we have a Flight Controller expecting % based on full charged battery. We have a battery board that shuts off at 3.0V ... put those together with a partial charged battery and you get the events that many have posted about.

The conclusion is :

Do not fly extended or serious missions with partial charged batterys.

Only fly limited if the battery is at least over 70% ...

Do not use the max flight you can get with full charged battery minus flight already to determine remaining flight time if you wish to fly again.

There is an exception of course. If you fly and then land BUT do not power down ... then of course display and battery remaining can be based on max flight time of a full charged pack minus already flown.

ALL batterys suffer self discharge. LiPo's being of the Lithium family suffer very low self discharge and can be charged day or so before and still be expected to deliver in the high 90's % power. But it still true that some charge has been lost.
If you set to 10 day factory default storage auto-discharge ............ I strongly suggest that flying with that pack after its stood for 4 - 5 days from full charge is not a good idea. I would suggest switching on the pack and connecting charger to top it back up.

Final item : In my opinion for the $5 or so it costs on eBay .. its worth every cent to have a Car Charger in every bag ... it solves most of the situation to provide peace of mind.

Nigel

ATJ Posted at 2018-7-28 05:12
Experience is the best teacher Captain. I've been using LiPo and LiIon for well over 10 years with my RC Helicopters.

Means ZIP here mate !!

I've been model flying for over 55yrs ... electrics for as long as I can remember ... NiCd's ... NiMh ... LiPo ... LiFe ... LiHv .... just to name a few.

Memory as you would claim is just not there .. what you are finding is Internal Resistance build up that then shortens the time before power drops off in use.

Good battery has x voltage drop and gives y flight time.

Old battery has much higher internal resistance and therefore higher voltage drop and therefore gives shorter flight time as it hits LVC ... or as I see in my Heli's / other models ... lack of power and throttle stick being pushed more to compensate.

Nigel

ATJ Posted at 2018-7-28 05:26
Smart Battery Technology only allows you to fly your Quadcopter at full power until the batteries are almost drained. Smart Technology is in the electronics paired with the battery NOT the battery itself. The batteries are still using the same lithium formula and can still aquire a memory.

Oh dear ....

I agree with you till you get on the Memory wagon again ... time for that old item to go the way of the NiCd ..... it has no place here with any Lithium based cells.

Nigel