Scary after critical battery, got questions!

Cyberpower678 · Feb 6, 2017

Woody67 said:
I stand corrected. I generally start back at low warning. Being it's always LOS I've never been forced to the critical point. I will readjustment my settings. Thanks for the heads up......are should I say drone down.

No worries.

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networth · Feb 6, 2017

I will simply get it back to home now ever time I get 30% warning.

stratos · Feb 7, 2017

I think I adjusted my Low battery warning to 25%.
I have heard that this is not a good idea , and I think I can agree. Better to be safe than sorry.

Will be adjusting my warning at 30% as soon as I reach home.

CactusJackSlade · Feb 7, 2017

Cyberpower678 said:
Somewhere, as part of the battery service, they need to be discharged after every 20 charges so the onboard software can stay properly calibrated to battery performance.

Yes, this actually does nothing to enhance the batteries actual performance.... this is all about re-calibrating the battery "gauge". This procedure will not make your battery "new" again... it will degrade over time and number of cycles just like any other battery.

Personally I do not like to run my batteries this low (the "8%") and since I fly conservatively and land with plenty in the tank I do not do this procedure but maybe once or twice during the life of my batteries...

Cyberpower678 · Feb 7, 2017

CactusJackSlade said:
Yes, this actually does nothing to enhance the batteries actual performance.... this is all about re-calibrating the battery "gauge". This procedure will not make your battery "new" again... it will degrade over time and number of cycles just like any other battery.

Personally I do not like to run my batteries this low (the "8%") and since I fly conservatively and land with plenty in the tank I do not do this procedure but maybe once or twice during the life of my batteries...

I am well aware of that but to have a battery report 60% when you actually have 40% isn't good either.

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anshuman127009 · Apr 23, 2018

CactusJackSlade said:
It tries to do the calculations but I doubt it can predict excess wind or obstacles it may need to avoid in those calculations... yes the 10% final warning is very unnerving, I wish there was a way to silence it as it breaks my concentration... I have only gotten to this point once. Even having to disengage the batter low warning is a pain...

Also, Sport mode is the least efficient way to come back home, it eats even more battery power... just keep in GPS mode and go full stick forward to home and that is pretty close to maximum efficiency.

This is what I experienced recently on my trip to Puerto Rico. There are 2 small uninhabited islands off the north east coast of PR. I flew my Mavic Pro at approx. 17 mph towards those islands. At a distance of about 3000 feet from the coast the battery hit 30%. I hit RTH button instantaneously. When it was approx. 400 feet from the coast the battery hit 10%. The RTH was cancelled and it initiated landing in the middle of the ocean. Luckily, it was an altitude of 300 plus feet. I immediately pushed my forward thrust to max and the drone started descending along an inclined path towards the coast. Fortunately, it landed 5 feet away from the coast. I don't know how I pulled that off but with all those warning sounds and visuals of your 2 months old drone landing in Atlantic ocean gave me a panic attack.

Just_nick · Apr 23, 2018

anshuman127009 said:
This is what I experienced recently on my trip to Puerto Rico. There are 2 small uninhabited islands off the north east coast of PR. I flew my Mavic Pro at approx. 17 mph towards those islands. At a distance of about 3000 feet from the coast the battery hit 30%. I hit RTH button instantaneously. When it was approx. 400 feet from the coast the battery hit 10%. The RTH was cancelled and it initiated landing in the middle of the ocean. Luckily, it was an altitude of 300 plus feet. I immediately pushed my forward thrust to max and the drone started descending along an inclined path towards the coast. Fortunately, it landed 5 feet away from the coast. I don't know how I pulled that off but with all those warning sounds and visuals of your 2 months old drone landing in Atlantic ocean gave me a panic attack.

That's why you enable smart RTH if you don't know how to plan your flights. The last 10% should be reserved for emergency, so you need to subtract 10% from whatever you're at to account for that.

Mossiback · Apr 23, 2018

triumphrider said:
Where in the manual does it say you need to discharge the battery to 8% every 20 charges? If this is something you personally do because you want to, that's fine, but I wouldn't be giving false information based on personal preferences.
Li Po batteries have come a long way and doing these complete discharge/recharge cycles aren't as necessary as they used to be.

As for periodic battery discharge. From DJI: https://dl.djicdn.com/downloads/mav...lligent+Flight+Battery+Safety+Guides+(EN).pdf

anshuman127009 · Apr 23, 2018

Just_nick said:
That's why you enable smart RTH if you don't know how to plan your flights. The last 10% should be reserved for emergency, so you need to subtract 10% from whatever you're at to account for that.

Also, another weird thing that I noticed while watching the crash video is that it didn't land at all because of the terrain mismatch. It just kept hovering almost 1 feet above the ground for another 2 - 3 minutes before I crash landed it.

msinger · Apr 23, 2018

Just_nick said:
The last 10% should be reserved for emergency, so you need to subtract 10% from whatever you're at to account for that.

The last 10% could really be 20%, 30%, etc. The Mavic will deem the Mavic battery to be critically low when it calculates it only has enough battery power left to safely land. The higher the Mavic is in the air, the sooner that auto landing will be triggered.

joejaxvic123 · Apr 23, 2018

Mossiback said:
As for periodic battery discharge. From DJI: https://dl.djicdn.com/downloads/mav...lligent+Flight+Battery+Safety+Guides+(EN).pdf

View attachment 36396

Is this something we should be doing? I sometimes run mine down to critical, 10% or less. So I am assuming my batteries are being treated correctly.

Mossiback · Apr 24, 2018

joejaxvic123 said:
Is this something we should be doing? I sometimes run mine down to critical, 10% or less. So I am assuming my batteries are being treated correctly.

I also run my batteries down to critical and have been for a year. I keep it close when the battery is getting low and land just before I am forced to. DJI's own battery recommendations are contradictory.

Item 1 states you should never over-discharge but item 3 states you should fully discharge every 3 months.

DJI batteries have electronics built in that will automatically partially discharge after 10 days (you can change this) and then enter "hibernation mode if depleted and stored for a long period". This is automatic and made to keep the batteries as healthy as possible. Keep in mind that if you push the battery button to see the charge status it will reset the 10 day clock.

ados_cz · May 28, 2018

On this subject, check my experience from 2 days ago :-D

Huge Bama Fan · May 29, 2018

Robbyg said:
100% Correct. My Mavic touches the ground at 30% or more charge.
Li batteries do not like deep discharges and having no reserves in the tank is dangerous..

Same here

hammick · May 31, 2018

I thought I read here that DJI does not recommend periodic deep discharges for the MP batteries. That is was required for the older drones.

hammick · May 31, 2018

This is from DJI's website:

8. How often should the Mavic Pro Platinum's Intelligent Flight Battery be charged and discharged?
The Mavic Pro Platinum's battery has a more advanced chip than earlier DJI intelligent batteries, so it does not need to be fully charged or discharged manually.

hammick · May 31, 2018

The above is only mentioned on the MPP FAQ. Absent on the MP FAQ.

Sorry for the multiple posts. The editing feature is not working for me.

tcope · May 31, 2018

hammick said:
I thought I read here that DJI does not recommend periodic deep discharges for the MP batteries. That is was required for the older drones.

They don't... but that comment was from over a year ago.

RoboticTundra · May 31, 2018

Li-ion cells will last longest if the middle part of the capacity is used. So, if you typically use 30% of the battery capacity it is best then to charge to 65% and then use it down to 35%. If you use 50% then charge to 75% and use down to 25%. This will provide the longest life, fastest recharge and most accurate usage gauge.

The bottom 5% of capacity should ideally never be used as it is the most damaging to the cells. From there the damage is approx equal at bottom and top and more damaging the farther from the 50% center. So better to charge to 95% and use to 10% than charge to 100% and use to 15%.

One problem is knowing what the endpoint reserves are? Many Li-ion battery packs have a 10% buffer on each end. Some better ones 15% at the bottom and 10% at the top. Does anyone know what, if any, buffer DJI builds in to the MPP batteries and how their charger manages this?

tcope · May 31, 2018

RoboticTundra said:
Li-ion cells will last longest if the middle part of the capacity is used. So, if you typically use 30% of the battery capacity it is best then to charge to 65% and then use it down to 35%. If you use 50% then charge to 75% and use down to 25%. This will provide the longest life, fastest recharge and most accurate usage gauge.

Lithium ion batteries don't suffer from any type of memory so using them from full charge is not only non-damaging, it's recommended. Reason being, they have a life expectancy based on cycles (charge/discharge). If you were to only use 50% of the battery charge, it would amount to one cycle, the same as using 70% or 80%.

Edit: However, there may be some merit to a partial discharge in that it does not stress the battery as much so its life may be extended. However, I don't think this applies to flying a drone. You want to be at the max capacity when starting out as the flight time algorithm would be more accurate.

RoboticTundra said:
The bottom 5% of capacity should ideally never be used as it is the most damaging to the cells. From there the damage is approx equal at bottom and top and more damaging the farther from the 50% center. So better to charge to 95% and use to 10% than charge to 100% and use to 15%.

DJI batteries contain electronics that won't allow the battery to discharge to 0%.

Recommending a 95% charge is simply bad advice.