Critical Low Power. Aircraft Landing.

[dwallersv]

Doesn't with that way with lipos and lihv. Try flying with batteries that are cooled to freezing temperatures and immediately fly with sport mode full throttle. The mavic will go straight into critically low battery landing mode.

All chemical batteries have an inverse relationship between internal resistance and temperature. It's because almost all chemical reactions speed up with increasing temperature, which looks like lower resistance electrically in a galvanic cell. See the
Arrhenius equation.

In contrast, when conductors are heated, the atoms in the lattice structure vibrate much more energetically, scattering the free (conducting) electrons more, interfering with the flow in the direction of current. This is effectively greater resistance.

 

[dwallersv]

Doesn't make sense. The higher the temperature the higher the resistance. Fact. Vice versa. I.e super conductors at absolute zero have zero resistance.

You need to graduate from Junior High. You'll cover chemistry and physics in High School, which will clear this up for you.

Fact.

 

[Tonka]

I have. They were set to discharge after 10 days. I never got a chance to fly because the weather was persistently bad, so they just sat there fully charged. When I did get a chance, they were discharged to 50%. As for draining below 10%, yes. I occasionally cycle the battery to recalibrate them, so I discharge to 3%. Also once doing a flight, I committed an oopsie during flight, and misjudged the wind speed so the drone fought its way back and I was keeping it up in the air until 6%.

Cyber, what do you use to discharge the batteries? I have one that has both LEDs in the middle lit and I think a discharge and recharge will reset the issue. Battery is now unusable. Don't mean to hijack. Just curious.

 

[dwallersv]

Cyber, what do you use to discharge the batteries? I have one that has both LEDs in the middle lit and I think a discharge and recharge will reset the issue. Battery is now unusable. Don't mean to hijack. Just curious.

Only way I know of (and have done) is to put the battery in the Mavic and fly it around, or let it hover nearby until it runs out.

I've done the latter a few times. Grab a beer.

 

[Cyberpower678]

Cyber, what do you use to discharge the batteries? I have one that has both LEDs in the middle lit and I think a discharge and recharge will reset the issue. Battery is now unusable. Don't mean to hijack. Just curious.

It sounds like the battery is suffering from a FW issue. I've never encountered this issue before. It won't deliver power to your Mavic?

 

[Tonka]

It sounds like the battery is suffering from a FW issue. I've never encountered this issue before. It won't deliver power to your Mavic?

Yeah, no deal with me on that. Because of the battery fault from the failed firmware update, DJI will not let the bird fly. I have plugged it in the blue metal multi charger i got from Amazon and tried draining it from there but no dice. I have 2 usb fans going since yesterday...

It supplies power constantly. The battery is always on. When I shove it in the Mavic, it powers on instantly.

 

[sparky1111]

You need to graduate from Junior High. You'll cover chemistry and physics in High School, which will clear this up for you.

Fact.

You need to learn some manners!
Fact!!

 

[charliesRig]

According to the flight log, you were flying into the wind in sport mode. This is apparent as you were seeing speeds around 36. You probably had around a 10 mph headwind. When you fly into the wind with sport mode the motors are pushed to maximum RPM which has considerable current draw on the battery. This causes some sag in the voltage due to the internal resistance of the battery. The resistance will be worse if the temperature outside is on the cool side or perhaps battery has not warmed up yet. As the battery warms up, it's performance will improve as internal resistance drops. Perhaps if you had started with a full battery, the battery would have warmed up during the flight and you wouldn't have seen the large voltage sag which triggered the low battery detection. Starting with a battery at ambient temperature and running it hard like that immediately causes a lot of sag in voltage.

In general, I would avoid using maximum thrust into the wind with sport mode, especially with a partially charged battery. It puts quite a strain on the battery. Sport mode with no wind or tail wind works fine, as the motors are not pushed as hard.

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Best analogy I've read ever.. Thank you for educating me on Mavic
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[dwallersv]

You need to learn some manners!
Fact!!

Okey dokey, Sparky!

 

[GatorWing]

I am using an Ipad mini on each of my Mavics and have the small map enabled in the lower right part of the screen so I can tap it to select either the full screen camera view or the full screen Google Earth view. Button C-2 on the back of my controller was programmed to do the same map toggle so it is a waste. I went in the software and reprogrammed C-2 to show me the battery info as shown in post #6 of this thread. Sometimes for giggles I look at the battery info to see what the cells are doing. I check more on windy days as that drains the batteries very quick .

 

[Cyberpower678]

Yeah, no deal with me on that. Because of the battery fault from the failed firmware update, DJI will not let the bird fly. I have plugged it in the blue metal multi charger i got from Amazon and tried draining it from there but no dice. I have 2 usb fans going since yesterday...

It supplies power constantly. The battery is always on. When I shove it in the Mavic, it powers on instantly.

If it's constantly supplying power but not letting you fly, then connect the Mavic with the battery into your computer and refresh the FW with DJI Assistance. It should also transmit the battery FW to the battery and it should reinstall.

 

[Brojon]

Bear in mind I haven't yet read thru all the messages but I will.
I reported the same thing on another board and was basically castigated for daring to fly on a battery that wasn't at 100% :/
I had exactly the same thing happen but I was not in sport mode. I am at the latest updates including the batteries.
I wast at 35% battery, flew up about 90 ft, flew appox 250 ft away to play with some gimbal settings on some features that encompassed a range of things. The bird was simply hovering in place pointed at a building roof expanse.
Anyway - the battery was still around 35% when the message appeared it was landing due to a critical battery level. I NEVER received any warning - just land message like it was at 10%
I stopped the descent and flew back. Landed fine. Checked settings and battery levels were at default of 30 and 10%.
Since then I have tested all three batteries for proper operation and no more weird stuff. Warnings and auto land work as advertised.

 

[Brojon]

You need to graduate from Junior High. You'll cover chemistry and physics in High School, which will clear this up for you.

Fact.

That wasn't called for. One of the things I like about this forum is the civility.
Can we keep it that way?

 

[Mavic Schwa]

Im still new with my Mavic. I like this picture. Is this native to the DJI app?

Yes you can do it too, go to the load screen before you enter the device and select the compass or little arrow pointing at a half cog. Anyway once in that screen, swipe upward on the phone and there you have your flight lists. To get the image above or below, select the flight in question and there you have it.

 

[dwallersv]

That wasn't called for. One of the things I like about this forum is the civility.
Can we keep it that way?

You're right.

Shouldn't post here after my 18yo daughter has pissed me off

 

[Brojon]

You're right.

Shouldn't post here after my 18yo daughter has pissed me off

You'll be a whole different person when she leaves to be on her own
My son and daughter are *much* more civil these days now they have a taste of adulthood and dad isn't such an idiot anymore.

 

[Oingo Boingo]

I have. They were set to discharge after 10 days. I never got a chance to fly because the weather was persistently bad, so they just sat there fully charged. When I did get a chance, they were discharged to 50%. As for draining below 10%, yes. I occasionally cycle the battery to recalibrate them, so I discharge to 3%. Also once doing a flight, I committed an oopsie during flight, and misjudged the wind speed so the drone fought its way back and I was keeping it up in the air until 6%.

There is your problem. You have effectively damaged one of the cells in your battery packs. I will toss that pack if I was you..... Or be VERY carefull when u fly. The next part will start to unravel as the battery becomes older... You will find that it will show 100% charged .. then within 5 Min of takeoff it will drop to 60% or lower and then minutes later it will hit levels below 30%. Storing lipos at anything above 30% is never advisable.. storing them at 100% is a definate NO NO.... It permanantly damages the battery

 

[Cyberpower678]

There is your problem. You have effectively damaged one of the cells in your battery packs. I will toss that pack if I was you..... Or be VERY carefull when u fly. The next part will start to unravel as the battery becomes older... You will find that it will show 100% charged .. then within 5 Min of takeoff it will drop to 60% or lower and then minutes later it will hit levels below 30%. Storing lipos at anything above 30% is never advisable.. storing them at 100% is a definate NO NO.... It permanantly damages the battery

Umm...I'm not the one with the problem. All of my batteries are fine, and operating nominally.

 

[Ian in London]

There is your problem. You have effectively damaged one of the cells in your battery packs. I will toss that pack if I was you..... Or be VERY carefull when u fly. The next part will start to unravel as the battery becomes older... You will find that it will show 100% charged .. then within 5 Min of takeoff it will drop to 60% or lower and then minutes later it will hit levels below 30%. Storing lipos at anything above 30% is never advisable.. storing them at 100% is a definate NO NO.... It permanantly damages the battery

I don't understand your concern here tho Oingo... The whole thing about DJI batteries is that they're 'Intelligent' and auto-discharge after 10 days over a period of a few days, precisely to avoid the damage you refer to....
I have always charged my batteries up to 100% and if I don't fly within 10 days, they start discharging... That's what they're designed to do... (and that's partly why they cost so much )

 

[Oingo Boingo]

I don't understand your concern here tho Oingo... The whole thing about DJI batteries is that they're 'Intelligent' and auto-discharge after 10 days over a period of a few days, precisely to avoid the damage you refer to....
I have always charged my batteries up to 100% and if I don't fly within 10 days, they start discharging... That's what they're designed to do... (and that's partly why they cost so much )

Ya the phantom batteries "intelligently" discharge as well. The golden rule with lipo packs are NEVER to leave it at full charge for longer than 3 days. The intelligence discharge is a backup safety thing meant as last resort to try and curb damage. Dunno... Just my opinion. Been doing Lipo RC powered craft for 12 years. And it's always ended up badly if left at full charge. Keep in mind the intelligent discharge will take 2 week's to discharge a pack of 3 cell lipos....