Confused about storage percentage for MA2 batteries

[houdinihound]

Hello everyone,

New to DJI products and just received my MA2. Reading through the manual (I know, who even does that? ) I see that it says the batteries will automatically discharge to 60% after 5 days.


Then a little later in the same manual there is a tip to always discharge your batteries to 30% or lower.


My older Yuneec Q500 batteries (non-intelligent) were maintained by a D100 charger that would set storage at approximately the 35% mark. After 4 years of use with 6 batteries and never had swollen batteries with that approach.

So my question is: anyone know why the auto-discharge function stops at 60% if it is recommended to discharge to 30% or lower?

Many thanks,

Joe

 

[Meta4]

So my question is: anyone know why the auto-discharge function stops at 60% if it is recommended to discharge to 30% or lower?

Probably just another example of DJI confusing documentation.
It's not the only one.

 

[new2mavic]

Discharging to < 30% when flying is to keep the battery in shape or the capacity may be reduced. For NiCd / NiMH battery, this is called the "memory effect" Memory effect - Wikipedia. LiHV batteries may have similiar issues.

After that the battery should be charged to 60% before storage. More than that swelling may occur.

The 30% and 60% recommendations apply to different things so there is no confusion.

For my M2, I typically discharge it to 15% when flying and charge it back to 50% before storage. I dont rely on auto discharging.

 

[Meta4]

LiHV batteries may have similiar issues.

This is just confusing misinformation.
Lithium batteries do not suffer from a memory effect.

 

[new2mavic]

This is just confusing misinformation.
Lithium batteries do not suffer from a memory effect.

May be the mechanism is different and it is not called memory effect but if DJI recommends discharging it to < 30%, I believe there are good reasons behind.

 

[Meta4]

May be the mechanism is different and it is not called memory effect but if DJI recommends discharging it to < 30%, I believe there are good reasons behind.

Like there's a good reason to recalibrate your compass after some number of days or moving some distance?
DJI documentation is full of confusing and contradictory information.

 

[new2mavic]

DJI documentation is full of confusing and contradictory information.

I dont see any contradiction in these 30% and 60% recommendations. Whether you agree with it is something else. Mixing them together is the real confusion I am afraid. Try to keep an open mind. Nobody knows everything.

 

[houdinihound]

Interesting viewpoints.
@new2mavic : from everything I've read @Meta4 is correct in saying there is no LiPo memory issue. But your point is that is advisable to cycle the battery down below 30 and then store at 60% (for reasons known to DJI) and therefore the information does not conflict.
@Meta4 : what % do you aim for/suggest to store your batteries (for let's say 3 weeks between flights)?

 

[new2mavic]

Interesting viewpoints.
@new2mavic : from everything I've read @Meta4 is correct in saying there is no LiPo memory issue. But your point is that is advisable to cycle the battery down below 30 and then store at 60% (for reasons known to DJI) and therefore the information does not conflict.

My point is there is no conflict in DJI's recommendation. If there is conflict the recommendation should not be doable. My own practice is to dischagre it to about 15% when flyaing and then recharge it to 50% before storage. It's perfectly doable and meet DJI's recommendation. Where does the conflict come from ?

Whether LiPo batteries will suffer from anything if routinely not discharged to below 30% is another matter. You can disagree with that and I will not argue and keep an open mind.

 

[new2mavic]

This can be the reason behind DJI's recommendation to discharge to < 30% . The instructions for an Apple iPad reads: “For proper reporting of SoC, be sure to go through at least one full charge/discharge cycle per month.”

BU-603: How to Calibrate a “Smart” Battery – Battery University

Learn why calibration is needed and how often it is required

batteryuniversity.com

 

[Piper J3]

I dont see any contradiction in these 30% and 60% recommendations. Whether you agree with it is something else. Mixing them together is the real confusion I am afraid. Try to keep an open mind. Nobody knows everything.

Ask Elon Musk - he does know everything battery....

 

[houdinihound]

This can be the reason behind DJI's recommendation to discharge to < 30% . The instructions for an Apple iPad reads: “For proper reporting of SoC, be sure to go through at least one full charge/discharge cycle per month.”

BU-603: How to Calibrate a “Smart” Battery – Battery University

Learn why calibration is needed and how often it is required

batteryuniversity.com

Interesting information, thanks for the link. I can imagine this calibration is required to provide better flight time remaining/time to auto RTH/time to forced landing estimates.

 

[StantonZ]

I will offer my 2 cents because I have a lot of experience with LiOn batteries (very similar to LiPo) as an EV owner.
LiPo batteries are used in a lot of portable/mobile applications due to their lighter weight and compact size, but share many traits with LiOn...like temperature and capacity sensitivity. The following "rules of thumb" will help extend the life of a LiPo battery (which unfortunately can't endure quite as many "cycles" as LiOn):

1. Don't use/charge "hot"; in other words, let it cool down before/after charging (charging any battery generates heat)
2. Don't store it at high SoC (state of charge); discharge to ~50% (e.g. anywhere from 30%-70%) if you aren't going to use it for more than a couple of days

For example, if you only fly on the weekend, make sure you fly/charge your batteries to at least 50%...and then charge to 100% the night before your flight the next weekend. Bottom line: it's not good to let them "sit" too empty (<20%) or too full (>80%).

 

[new2mavic]

Just came across this article : BU-702: How to Store Batteries – Battery University

The best state-of-charge for storage seems to be 30 % ~ 40 %, not 60% mentioned in the DJI manual.

 

[houdinihound]

Just came across this article : BU-702: How to Store Batteries – Battery University
The best state-of-charge for storage seems to be 30 % ~ 40 %, not 60% mentioned in the DJI manual.

However that article refers to LiOn batteries... not LiPo. Interesting info nonetheless.

 

[new2mavic]

However that article refers to LiOn batteries... not LiPo. Interesting info nonetheless.

Li-polymer Battery: Substance or Hype? – Battery University

Find out what made lithium-polymer battery systems popular. Most users cannot distinguish between a regular Li-ion and one with polymer architecture.

batteryuniversity.com

 

[MaverickMavicMark]

This can be the reason behind DJI's recommendation to discharge to < 30% . The instructions for an Apple iPad reads: “For proper reporting of SoC, be sure to go through at least one full charge/discharge cycle per month.”

BU-603: How to Calibrate a “Smart” Battery – Battery University

Learn why calibration is needed and how often it is required

batteryuniversity.com

Rechargable battery tech is one of the internet's topics most full of horse-hockey posts.

Thank goodness the battery university website is referenced here!