<50% batt life to 3% instantly experiment

[Shazbot4]

I'm just curious. What battery % would you like the safety landing limit to be set at then? (Keeping in mind that this is a figure that DJI have put in place to stop individual cells drawing below a set voltage and therefore preserving the life of the battery)
Would you be happy if it was 3%? Or do you want removed all together?
We have already established that batteries that are dropping from 50% to 3% rapidly are not the norm. So under normal flying conditions the 10% threshold would be fine as you shouldn't be flying anywhere near that limit.

If you changed the limit to 3% then the faulty batteries would still be thrown into a forced landing.
If you removed it all together then I would estimate that you probably have 10-15 seconds max to get the I1 on the ground before there was just no more voltage left whatsoever causing total shut down of all systems and who know what issues that may cause long term!
In either situation I would say the outcome has a strong possibily of being less than desireable.

The point I am trying to make is that this forced landing limit of 10% is a safety margin. If it was removed it could result in a damaged battery and possibly damaged circuits/components/hardware......

personally I would remove anything that can shut the motors down and just let the individual set the warning and critical warning where ever they want down to 1% and just let it be a warning and nothing else.

I think everyone agrees running batteries down to zero is bad for their life span. who cares. as of right now the inspire software thinks it better to kill the motors below 10% and crash it's self to preserve the cells. last I checked most crashes the battery gets totaled anyway so the whole purpose of the auto landing at 10% is nothing but a liability.

let people run batteries down to zero and burn them out. after they spend 2000 on new ones maybe they will figure it out, even if they don't at least they will maintain control while flying if they do wanna take it down to zero every time and us more responsible ones wont have this huge fear of flying past 30% as it is.

there have been so many battery firmware updates no one can really know the whole story with these things. so I think the simplest solution is the best.

 

[Carlsberg]

It's best to think about landing at the 30% warning and never discharge past 20%
There is no reason to stress the cells and kill off cycles, (unless of course you are trying to make it home from a top secret mission)
That's the way we all treat lipos at our club, (and we rarely ever have a problem with them)

 

[Shazbot4]

right. so in that situation should the punishment for pushing the battery once in a while past the normal safe discharge level in case of emergency be a 2000 dollar crash?

 

[Whodatdere]

It's best to think about landing at the 30% warning and never discharge past 20%
There is no reason to stress the cells and kill off cycles, (unless of course you are trying to make it home from a top secret mission)
That's the way we all treat lipos at our club, (and we rarely ever have a problem with them)

Just out of curiosity how is running the pack down killing the battery. Every 10 cycles you are supposed to run them down to 5% or less to calibrate the battery?

 

[Kilrah]

right. so in that situation should the punishment for pushing the battery once in a while past the normal safe discharge level in case of emergency be a 2000 dollar crash?

But that crash will happen even without the safety! If you're that far down the battery voltage will anyway not be sufficient to give the motors enough power to keep the aircraft in the air more than a couple of seconds longer! Should the battery not shut itself down at 3.1V/cell it would fall down to 2.5 or less in seconds, which would not only damage the battery (not important indeed) but not be able to hold the bird in the air anymore anyway. The current safety system is designed to bring the bird down *under control* before it goes down *without control* because it doesn't have enough juice to hold in the air anymore... and you're asking to remove that safety.

If these seconds are what it takes to prevent you from crashing your bird it's nobody's fault but yours for having pushed that far past all reasonable safety margins, and whether thresholds are "defined" as where the bird falls at 0%, 3%, or 10% changes nothing, you simply need to know what that point is and never ever get any close to it.

 

[tassieflyer]

You should NEVER be flying your packs down to 10%. If you were flying anything RC you would probably lose it if you were flying your packs down to those sort of levels and you would get the same behaviour from any lipo pack.

A smarter man than me told me use the 30/30/30 rule. Fly out for 30%, allow 30% for the return, 30% reserve. The remaining 10% is not for sale.
In Tasmania, Australia, the government says: the 100 Klm road speed limit is not a target speed, drive to the conditions. Take a moment to think of that statement in context to flying your bird.

 

[Scotflieger]

Can I suggest that this discussion has reached its conclusion and any further contributions or opinions are pointless? Shazbot4 obviously has his fixed views. He is right and all others do not know what they are talking about (even if they are basing their advice on long experience and reading the manual). I know what route I shall be taking.

 

[DaBone]

this is just getting comical now. you guys are going around in circles. I can't add anything new because i'll just be repeating myself.

i'll leave it at this. DJI will crash your inspire if you fly the battery to 10%. it has nothing to do with the hardware, it's all the software and there is no logic behind it.

Take a look at my post above..

 

[Luis Morales]

i really don't see the point here.

this can happen with many lipo batteries no matter the price for several reasons. first a not fully charged battery can have a sudden drop, the voltage of a battery under load and no load can very a lot, and depending on the load it can be dramatic. secondly a cell can fail (this had happen to me on a discovery pro quadcoper using a 4s bat and in a custom y6 5kg using 8s) doest not matter if the battery was 150$ or 500$ they all can fail.

DJI can add as much intelligence as they want to the battery but they cant avoid physical failures. maybe they can make a TB49 battery with 7 cells and have 1 for redundancy.

 

[Frank508]

So the "Max Flight Time Approximately 18 minutes" is based on 100% to 30%, 10% or 0%?

 

[richard.dyson1]

So the "Max Flight Time Approximately 18 minutes" is based on 100% to 30%, 10% or 0%?

I don't know the answer to this frank but it's fairly redundant as there are so many variables that effect flight time.

I fly to 30% then land rather than flying for x minutes.

Sent from my GT-I9505 using Tapatalk

 

[Luis Morales]

So the "Max Flight Time Approximately 18 minutes" is based on 100% to 30%, 10% or 0%?

the max flight time is based on 100% hover until it autolands.

 

[Carlsberg]

I don't know the answer to this frank but it's fairly redundant as there are so many variables that effect flight time.

I fly to 30% then land rather than flying for x minutes.

Sent from my GT-I9505 using Tapatalk

Same here.
Like the rest of you, I fly in a multitude of conditions and monitor my mAh %
I have over 200 flights and have not "timed" one of them, nor have I even once cared to go back and look how many minutes/seconds I was in the air (who cares?).
I only care about my footage and my battery life when flying my Inspire
(flights rules of course are always followed, I care about them too)

Carl

 

[Mark Krieger]

I mentioned in my previous post that I went from 61% to 3% in about a min and a half. Then, when I landed (safely by the skin of my teeth!), the battery reported 55%. I rarely will fly on a less than 100% charge, but in this particular case, I wanted to get up as fast as possible to catch a small fire that started in the forest behind my house. I brought the bird up and out about 150 feet. I wasn't going too far or for too long.

Now, I totally understand and support the 30% warning and 10% autoland. Got it - and I haven't changed the default and I'm very compliant about not pushing the limits.

I'm also beginning to understand how these batteries work.

Now, what I can't get my head around are the hard and fast rules of flying with these batteries.

First, let's say that I start at 100%. I shoot some video and I land at 75%. I review said video and decide that I didn't get the shot I wanted. At this point, should I swap batteries out if I want to fly, say another 5 min? If not, what is the threshold? 60%? 52%? 47%?

Second, regarding storage. The default auto-discharge cycle happens at 10 days, correct? So this means that if I charge the batteries and store them for 3 days, it's safe to take off with them assuming they read 100%, yes?

Now, regarding the auto-cutoff rules DJI has programmed... I would think that a 'second opinion' failsafe in the software would make sense. If the software senses a very sudden drop, then check again in a few seconds and abort the auto-landing. Also - ALWAYS give the pilot the ability to cancel the auto-landing and take over.

I would much prefer to replace a 200 battery than have to replace a 3k drone - and pay for the damage that it caused from falling out of the sky.

 

[Luis Morales]

I mentioned in my previous post that I went from 61% to 3% in about a min and a half. Then, when I landed (safely by the skin of my teeth!), the battery reported 55%. I rarely will fly on a less than 100% charge, but in this particular case, I wanted to get up as fast as possible to catch a small fire that started in the forest behind my house. I brought the bird up and out about 150 feet. I wasn't going too far or for too long.

Now, I totally understand and support the 30% warning and 10% autoland. Got it - and I haven't changed the default and I'm very compliant about not pushing the limits.

I'm also beginning to understand how these batteries work.

Now, what I can't get my head around are the hard and fast rules of flying with these batteries.

First, let's say that I start at 100%. I shoot some video and I land at 75%. I review said video and decide that I didn't get the shot I wanted. At this point, should I swap batteries out if I want to fly, say another 5 min? If not, what is the threshold? 60%? 52%? 47%?

Second, regarding storage. The default auto-discharge cycle happens at 10 days, correct? So this means that if I charge the batteries and store them for 3 days, it's safe to take off with them assuming they read 100%, yes?

Now, regarding the auto-cutoff rules DJI has programmed... I would think that a 'second opinion' failsafe in the software would make sense. If the software senses a very sudden drop, then check again in a few seconds and abort the auto-landing. Also - ALWAYS give the pilot the ability to cancel the auto-landing and take over.

I would much prefer to replace a 200 battery than have to replace a 3k drone - and pay for the damage that it caused from falling out of the sky.

the rules are as with any other battery forget about the **** % it very complicated to do that accuratly.

ideally you don't want to go bellow 3.2V per cell to be on the safe side you usually leave them at 3.4 3.3 so check your per cell voltage and your total voltage (always under load, that means take off and read the value while in the air) so min safe voltage its 20.4V min as in land right now!.

also check your mah consumption after you flights to keep a lipo battery healthy you usually want to use only 80% of the energy stored that means that for the TB47 bat you should use no more than 3600mah and for the TB48 4560mah.

with the inspire or any other multi rotor using lipo batteries what i usually do is take of check for 10/15 secs the voltage to double check is not dropping too fast (lipo battery voltage drops a lot faster when the battery is almost depleted) and usually do so fast movement like full forward for a bit and see that the V is still constant (fast movement will increase load.)

 

[Shazbot4]

Can I suggest that this discussion has reached its conclusion and any further contributions or opinions are pointless? Shazbot4 obviously has his fixed views. He is right and all others do not know what they are talking about (even if they are basing their advice on long experience and reading the manual). I know what route I shall be taking.

i dont know if this is sarcasm but what route would that be?

there's pretty much is one school of though i and most everyone agrees with. dont fly below 30%. again this isn't written anywhere by DJI. everyone agrees any battery can act up and skip voltage levels. batteries can go dead extremely quickly in flight with any aircraft. just nature of the beast. we got it. no one is arguing this right? a battery can go from 100% to dead. i've read it about 10 times in this thread from different people.

why 30% land? why not 25? or 50? or 2? or 70? why aren't these the magic and all holy numbers to land at? i'll tell you why.

this is where a lot of people here fail to make the connection.
anything past 30% is just dangerous for the inspire's welfare. why? because 30% gives you a 19% buffer from all hell breaks loose and your no longer in control of the aircraft, the auto land feature is. DJI's programming is the fear and why we have 30% landing mentality.
if the auto land was at 40% we would land at 70% wouldn't we. if the voltage skips around no less then 19% should be enough to keep you above the 10% time to shut it's self down. this isn't the case at all is it?

the inspire with all it's programming is suppose land at 10% battery on it's own. the user is 100% dependent on this feature working perfectly every time because there is no way to stop it. if it fails the result is crashed inspire. how often does everything work on every inspire every time correctly? never. if you say it always works perfectly then good for you.

30% isn't enough of a safety blanket when the problem is <50% to about 3% instantly, fully charged battery or not. DJI's programming causes the crash, not the pilot. at the time of any of these crashes there is still plenty of power for the inspire to remain in the air for at lest 5 minutes, probably more, kinda insult to injury everything shutting down and crashing when there is still power to fly after the fact. the auto pilot app shuts down the motors at anything below 10% and kablamo. if this didn't exist then this conversation would be completely different. we wouldn't have everyone bible thumping 30% land every chance they got would we?

DJi's programming is the fear of a crash and 30% land was invented to avoid it. remove the 10% auto land and fear below 30% leaves with it. now please argue with me

 

[Scotflieger]

You have repeated yourself more than once or 30 times. You are going to give yourself a heart attack worrying over something you are not going to get changed. Live with it or sell your DJI Inspire and buy a machine that doesn't have these constraints. Your choice. Please don't keep going on about it - we've heard what you have to say.

 

[Shazbot4]

thought it was sarcasm. if you don't care what i have to say why respond?

 

[Kilrah]

the inspire with all it's programming is suppose land at 10% battery on it's own. the user is 100% dependent on this feature working perfectly

Absolutely not. The user is 100% dependent on and responsible for never reaching 10% the level he's set as "critical" in the app and that triggers the autoland, i.e. always land before. Can't blame DJI if he doesn't...

Again the "sudden drop" is unrelated and a completely different case. If it happens - well, bad luck. Safety, no safety, percentage or voltage... nothing will solve the problem.

 

[The Editor]

Absolutely not. The user is 100% dependent on and responsible for never reaching 10% the level he's set as "critical" in the app and that triggers the autoland, i.e. always land before. Can't blame DJI if he doesn't...

Again the "sudden drop" is unrelated and a completely different case. If it happens - well, bad luck. Safety, no safety, percentage or voltage... nothing will solve the problem.

Agreed - Except flying the platform on totally different battery chemistry.

This is just the nature of Lipo batteries and every RC flying thing I have ever put in the air has had a low voltage cut off in the esc's. Once you hit that it's buy buy multirotor (Helis you can auto-gyrate and fixed wing glide but a multi becomes an ungraceful brick at that point!).

OK - I don't know about anybody else but I'm getting dizzy here - going round in circles.