Airdata Battery Maintenance Recommendation

[Amarand]

Hey all!

I've been using Airdata for a bit to keep track of maintenance of my Mavic Air and its three batteries.

One of the things they recommend at the "Basic" battery service is to perform the following:

Slower Deep Cycle Method:

1. Fly until battery level reaches 25%-30%
2. Allow battery to cool completely to room temperature
3. Put battery back in and turn on aircraft (optionally starting motors with no propellers) and allow battery to discharge until it gets down to 8%, or until the battery can no longer be turned on. Launch the DJI GO app to check battery levels.
   Important: NEVER fully discharge the battery to 0% - it can cause permanent damage
   Tip: With engines stopped, the battery seems to drain about 1% every 5 minutes or so
4. Allow the battery to cool completely again to room temperature
5. Recharge battery normally

So what I'm curious about is section 3 "(optionally starting motors with no propellers)" which I've tried. Unfortunately, the only way I know how to do this is to perform a take-off, which throws some fun errors:

Mode Mode changed to AutoTakeoff
14% Battery at maximum distance
Data Loss Downlink data connection lost for 1.2 seconds
* Warning Propeller Fell Off. Motor Idling (Propeller Loose or Missing)
* Warning Not Enough Force/ESC Error. Propeller Fell Off
* Warning Propeller Fell Off (repeated 4 times)

Assuming I want to follow these recommendations, what's the best way to accomplish step 3?

 

[msinger]

You can start the motors by doing a CSC.

FWIW, I don't recommend deep cycling DJI batteries. There is no proof to show it's beneficial for DJI batteries.

 

[brett8883]

Hey all!

I've been using Airdata for a bit to keep track of maintenance of my Mavic Air and its three batteries.

One of the things they recommend at the "Basic" battery service is to perform the following:

Slower Deep Cycle Method:

1. Fly until battery level reaches 25%-30%
2. Allow battery to cool completely to room temperature
3. Put battery back in and turn on aircraft (optionally starting motors with no propellers) and allow battery to discharge until it gets down to 8%, or until the battery can no longer be turned on. Launch the DJI GO app to check battery levels.
   Important: NEVER fully discharge the battery to 0% - it can cause permanent damage
   Tip: With engines stopped, the battery seems to drain about 1% every 5 minutes or so
4. Allow the battery to cool completely again to room temperature
5. Recharge battery normally

So what I'm curious about is section 3 "(optionally starting motors with no propellers)" which I've tried. Unfortunately, the only way I know how to do this is to perform a take-off, which throws some fun errors:

D00m 14s0.0 ft0 ftModeMode changed to AutoTakeoff 00m 15s0.0 ft0 ft

14% Battery at maximum distance E00m 17s0.0 ft0 ftData LossDownlink data connection lost for 1.2 seconds F00m 17s0.0 ft0 ftWarningPropeller Fell Off. Motor Idling (Propeller Loose or Missing) G00m 18s0.0 ft0 ftWarningNot Enough Force/ESC Error. Propeller Fell Off H00m 18s0.0 ft0 ftWarningPropeller Fell Off (repeated 4 times)

Assuming I want to follow these recommendations, what's the best way to accomplish step 3?

Yea don’t do that I can’t believe they would recommend that. Only do this if you have cells that are unbalanced but you can just start up the motors and let them idle on the ground or better yet take off and hover in place till the drone auto-lands.

Again only do this if your cells are unbalanced because if they aren’t it’s pointless just putting unneeded stress on the battery.

 

[Deleted member 94047]

* Warning Propeller Fell Off (repeated 4 times)

That is indeed a funny looking error. I always thought GO4 will refuse to allow you to take off while props were removed.
As for how you can do step three, what msinger said above. But why do you need to do this?

 

[Amarand]

You can start the motors by doing a CSC.

FWIW, I don't recommend deep cycling DJI batteries. There is no proof to show it's beneficial for DJI batteries.

Cool, thanks for the tip! I've never used the "CSC" before. Are there real-world uses for it, aside from just firing up and stopping the motors at will?

 

[Amarand]

Yea don’t do that I can’t believe they would recommend that. Only do this if you have cells that are unbalanced but you can just start up the motors and let them idle on the ground or better yet take off and hover in place till the drone auto-lands.

Again only do this if your cells are unbalanced because if they aren’t it’s pointless just putting unneeded stress on the battery.

Well, and really, the only difference between a flight with a battery, running it down, and a flight with a battery that I then turn into a basic battery maintenance, is running it down (after cooling) into the 8% range, letting it cool again, and then fully charging it.

Is it voodoo? (If so, maybe they shouldn't be recommending it?) Or is it something that depends on your style of charging?

 

[Amarand]

But why do you need to do this?

It's a recommendation from the Airdata web-site for battery maintenance. Maybe they're wrong? I mean, if it harms the battery, that sucks.... But which part is objectionable? Running it down to 8%?

 

[Deleted member 94047]

It's a recommendation from the Airdata web-site for battery maintenance. Maybe they're wrong? I mean, if it harms the battery, that sucks.... But which part is objectionable? Running it down to 8%?

Yes, the running them down to 8% part doesn't seem particulalry useful. If anything, it will stress the batteries even more and do more damage than good. The whole thing makes no sense unless you have some very unbalanced cells. Is AIRDATA showing you significant deviations between your battery cells? Significant as in more then 0.1V difference between cells.

 

[Deleted member 94047]

Cool, thanks for the tip! I've never used the "CSC" before. Are there real-world uses for it, aside from just firing up and stopping the motors at will?

You can use this method for manual take off too. Start motors with the CSC technique, and then push the left stick up to take off.

 

[Amarand]

Yes, the running them down to 8% part doesn't seem particulalry useful. If anything, it will stress the batteries even more and do more damage than good. The whole thing makes no sense unless you have some very unbalanced cells. Is AIRDATA showing you significant deviations between your battery cells? Significant as in more then 0.1V difference between cells.

The "Basic Battery Maintenance" recommendation is every 20 flights or so. Not based on balance of battery cells. I should probably ask them about that...like, if it's a general recommendation they got from somewhere, or from a battery manufacturer...? Maybe it's a way to get you to buy more batteries more often? ?

All of the other recommendations for the Mavic Air were very craft-and-app specific, and all things that I would absolutely recommend doing, like inspecting all the components at various intervals.

Then again, I used to work on helicopters in the Army, so I'm used to regular maintenance schedules and doing what I'm told based on a checklist. ?‍

 

[Amarand]

You can use this method for manual take off too. Start motors with the CSC technique, and then push the left stick up to take off.

The "CSC Technique" is probably something I should learn/practice, right? Just so I have it in my toolkit, so to speak.

 

[brett8883]

The "Basic Battery Maintenance" recommendation is every 20 flights or so. Not based on balance of battery cells. I should probably ask them about that...like, if it's a general recommendation they got from somewhere, or from a battery manufacturer...? Maybe it's a way to get you to buy more batteries more often? ?

All of the other recommendations for the Mavic Air were very craft-and-app specific, and all things that I would absolutely recommend doing, like inspecting all the components at various intervals.

Then again, I used to work on helicopters in the Army, so I'm used to regular maintenance schedules and doing what I'm told based on a checklist. ?‍

The "CSC Technique" is probably something I should learn/practice, right? Just so I have it in my toolkit, so to speak.

I think they lost all credibility when they said to dry run your motors.

CSC is just starting the motors and when you pull up on the throttle it does the exact same thing as auto-take off. I honestly find it to be much faster and easier. Already have fingers on controls and off she blows. Thats how I always take off. Also allows you to see the props rotating before takeoff so if there's a problem you are still on the ground and can cut the motors.

If you really want something to do as regular maintenance take a vacuum cleaner with a car detailing hose attachment and go over all the crevices to get all the dust and junk out of it especially the motors. Thats about all you really have to do

 

[brett8883]

Well, and really, the only difference between a flight with a battery, running it down, and a flight with a battery that I then turn into a basic battery maintenance, is running it down (after cooling) into the 8% range, letting it cool again, and then fully charging it.

Is it voodoo? (If so, maybe they shouldn't be recommending it?) Or is it something that depends on your style of charging?

Its to rebalance the cells if they are out of balance but otherwise is pointless.

 

[msinger]

Cool, thanks for the tip! I've never used the "CSC" before. Are there real-world uses for it, aside from just firing up and stopping the motors at will?

CSC does nothing but start or stop the motors. When not auto taking off and landing, most people use it to start and stop the motors. It can also be used to stop the motors mid-flight (for emergencies).

After landing, it's better to hold the throttle down (left stick in Mode 2) for a few seconds to stop the motors. While a CSC can accomplish the same thing, it sometimes causes the aircraft to tip when not performed cleanly.

 

[WithTheBirds]

It would be interesting to learn what explanation Airdata might provide for including this maintenance recommendation.

It is easy to appreciate how it might have great relevance to earlier generations of.battery management schemes. Simple coulomb counting schemes are unable to accurately account for the effects of cell aging without a routine deep discharge to provide for calibration.

The BMS SOC in our current DJI packs are capable of reporting capacity to within 1% accuracy over the life of the cells with no need for deep discharge to calibrate. If your interested in the technology have a look for the white papers discussing what Texas Instruments, the SOC supplier to DJI, calls “impedance track” and “gas gauging” .

 

[WithTheBirds]

Its to rebalance the cells if they are out of balance but otherwise is pointless.

The cells are balanced by use of bleed resistors as required during the constant voltage phase at the end of the charge cycle.

Yes, an unbalanced pack may seem to come good if charged from a lower state of charge however it will almost certainly return to an unbalanced state after use. The cell imbalance is due to unequal internal resistances of the cells. Deep discharge will not correct this.

 

[Amarand]

If you really want something to do as regular maintenance take a vacuum cleaner with a car detailing hose attachment and go over all the crevices to get all the dust and junk out of it especially the motors. Thats about all you really have to do

I have a nice tech blower.



I always get in there if I see anything.