Manually Discharging Batteries

[GadgetGuy]

Anything below 3.5V under load is playing with fire. It ages the battery quickly and once you've done it enough times, your battery's voltage will sag when you don't expect it.

I don't doubt you. A brief review of my M3 AirData logs reveals that 3.5V under load is still not being reached at 6% remaining battery, when my landing goal is between 5% and 10%. As you can see in the AirData "Cell Voltage ((4 cells)” graph below, it doesn't even drop below 3.6V at 6% remaining under load. That is consistent with your 3.60V under load trigger to land, except on the M3, it's around 6% remaining battery, instead of 20-30% remaining battery.

 

[GadgetGuy]

I

I flew past the point I decided to make the emergency landing but the wind was too strong to make any forward motion... lesson learned to set her down and not chance it. So I turned around and flew with the wind and was seconds from making a successful landing but my battery still would had been toast I guess! lol.... in other words.... lucky to even get my drone back because I was over the ocean at 0%!!!! well if I had landed at the same place.... right away my battery would had been fine.... lesson learned after making thousands of drone flights this was a first... well second but not with this drone! lol but the drone landed fine. Air 2s

Once you reach 0%, and aren't already within 500 feet, best to ditch land at the first dry land opportunity to save the bird and the battery. Having an alternate landing site scoped out ahead of time is prudent. Be prepared for the unexpected!

 

[ianwood]

That's right where you want to be. DJI has been pretty conservative with their percentages. Good to see.

 

[GadgetGuy]

That's right where you want to be. DJI has been pretty conservative with their percentages. Good to see.

Yes, unlike the old days, where 0% really meant zero!

 

[Mavic Merrick]

The only reason I have to discharge my batteries is if I am going on an airplane. The reason for this is because I fly about every day and discharging is not sensible for my situation in general. But, when I do have to discharge for airline travel and I cannot fly I just put my drone somewhere safe and idle the propellers until they are down to about %40.
Hope this helps!

 

[pchaps]

Percentages are indeed tricky. DJI's 0% now still leaves two minutes of flight time in the tank. Mavic 3 does always display all cell voltages in the Fly app under Safety/Battery, and I carefully screenshot the individual voltages after landing, after first screenshotting the remaining battery, so I, too, am tracking the cell voltages religiously, but not under load. For a frame of reference, 3% remaining battery is still 3.65V per cell, as displayed in the Fly app. 10% remaining is well above that. Under load values will understandably be lower than that, but not dangerously so. The M2P displays voltage on the main screen under load in Go 4, and won't drop below 3.5V per cell until well below 0% remaining. M3 is likely very similar, but I will now start checking the M3 under load for comparison.

>The M2P displays voltage on the main screen under load in Go 4, and won't drop below 3.5V per cell until well below 0% remaining.
Great info. M2P and Go4 here--what would it be prudent "landing battery level" for me to land my M2P -- would that be 1bar on the battery level indicator? Also thanks for knowing that the actual battery voltage display on my Go4 as seen on iPad? Today I am working through all the menus and reading the manual with props off.

 

[pchaps]

The only reason I have to discharge my batteries is if I am going on an airplane. The reason for this is because I fly about every day and discharging is not sensible for my situation in general. But, when I do have to discharge for airline travel and I cannot fly I just put my drone somewhere safe and idle the propellers until they are down to about %40.
Hope this helps!

I use Hanatori charger that has a storage charge setting. It can charge or discharge as needed. I have Mavic 2 and did the same for Air 2s. No need to spin your motors to discharge batteries -- also no need for the drone to get hot while stationary!

 

[Logger]

The only reason I have to discharge my batteries is if I am going on an airplane. The reason for this is because I fly about every day and discharging is not sensible for my situation in general. But, when I do have to discharge for airline travel and I cannot fly I just put my drone somewhere safe and idle the propellers until they are down to about %40.
Hope this helps!

Why do you “have to” discharge for airline travel?

 

[Meta4]

Why do you “have to” discharge for airline travel?

You don't ... it's just a myth

 

[Mavic Merrick]

You don't ... it's just a myth

Not required but a good safety practice.

 

[CanadaDrone]

It's good practice, but the reality is that most people's smartphones, tablets, laptops, noise cancelling headphones, Nintendos, etc. with a LiPo in it on that plane are probably charged to max before the flight, and virtually every airplane these days provides charging ports which many people use to keep those devices at 100% for the entire flight. So while it's true that it's safer, you're already surrounded by (depending on the aircraft) perhaps hundreds of people, many of which couldn't even tell you what a LiPo was let alone safest transportation procedures

What the airlines are concerned about in the cabin are damaged batteries, which is why they always ask for you to call a flight attendant if you drop a device between the seats, so you don't recline or something and snap it in half.

 

[Jagerbomb52]

Information from Air Canada

Guidelines for Batteries | CATSA | ACSTA

This page provides tips for travelling with batteries, including how to properly pack spare batteries.

www.catsa-acsta.gc.ca

 

[pchaps]

Why do you “have to” discharge for airline travel?

Bc if the LiPo did burn while onboard the airliner, in the cabin, it would have less energy stored in the cells. Also if the battery had an issue, it the chemistry inside would not be under the stress of a full charge. Anything to mitigate the severity and potential for a LiPo fire. One DJI battery on fire in the cabin, would create an air emergency and require an emergency landing. Then, if the fire spread to other batteries, and ignited some other material, it could be disasterous.

 

[Meta4]

Bc if the LiPo did burn while onboard the airliner, in the cabin, it would have less energy stored in the cells. Also if the battery had an issue, it the chemistry inside would not be under the stress of a full charge. Anything to mitigate the severity and potential for a LiPo fire. One DJI battery on fire in the cabin, would create an air emergency and require an emergency landing. Then, if the fire spread to other batteries, and ignited some other material, it could be disasterous.

If it was important, airlines would make a big deal about it (but they don't).
As explained in post #31, almost all passengers have LiPo batteries, not just the drone owners.

 

[CanadaDrone]

Basically every 'rule' in commercial aviation has to do with safety, and pretty well every inconvenience passengers face during traveling is for their own safety (as hard as that may be to believe sometimes).

If airlines cared the slightest bit about having LiPos in the cabin, they would ban them completely as the risk tolerance on commercial flights is very low. As mentioned earlier, when it comes to batteries, they are only concerned about fires, so they ask you to get a flight attendant to help you retrieve your phone if you drop it between the seats. This is also why you cannot put them in your checked baggage where they are unsupervised, and this is also why you can't bring on a battery larger than 100Wh.

It's just like how it doesn't really matter if you put your device in airplane mode or not during the flight - if it were an actual safety concern, you can bet it would be strictly enforced and carry a hefty penalty for noncompliance. The reason they ask you to do so is because sometimes the interference from everyone's' phone increasing power to search for a signal the further you get away from the towers can cause some extra noise/interference with the radios pilots use to communicate with air traffic control. As long as there isn't an entire plane full of people with their phones on, it's generally a non-issue. It's in your best interest to enable it anyway because your phone won't lose nearly as much battery over the duration of the flight, and you can't use the cellular radios even if you wanted to.

 

[explorer76]

Hey, check out Phantom Angel - they build a gadget especially for discharing DJI batteries.

 

[Wave Reflections]

Hey, check out Phantom Angel - they build a gadget especially for discharing DJI batteries.

Great - just what I was looking for! Cheers!

 

[GadgetGuy]

Hey, check out Phantom Angel - they build a gadget especially for discharing DJI batteries.

At that price, you can buy another battery when your original loses full capacity after 75% of the projected life from "perfect" storage maintenance!

 

[UAVquadman]

At that price, you can buy another battery when your original loses full capacity after 75% of the projected life from "perfect" storage maintenance!

"DJI recommend deep-discharging (cycling) every 20 cycles. The Angel deep-discharges drone batteries safely and reliably, at a constant rate of 1C ensuring minimal wear to the batteries." Deep-discharging! no way!! I do this when I fly my drone anyways! LOL... I invented a battery discharger that used a relay. I should take a photo of it and post it! LOL... (for NiCad batteries)

 

[Jagerbomb52]

"DJI recommend deep-discharging (cycling) every 20 cycles. The Angel deep-discharges drone batteries safely and reliably, at a constant rate of 1C ensuring minimal wear to the batteries." Deep-discharging! no way!! I do this when I fly my drone anyways! LOL... I invented a battery discharger that used a relay. I should take a photo of it and post it! LOL... (for NiCad batteries)

DJI used to put deep discharge in their manuals but not any more for their newer drones. Its not in my manual for my air 2S. I have a charger that will discharge my battery if I am unable to fly it. I usually will let it go for 3 days before discharging. Old habits are hard to break.