Batteries dropping mAh after every charge

[Mark Csabai]

Hi,

I have had my Spark for about three weeks now, flown it ,maybe ten times.

I have noticed a significant drop in the mAh after I charge the batteries.

Battery one (three weeks old) 9 charges - from 1480 mAh - 1382 mAh
Battery two (one week old) 2 charges - from 1480 mAh - 1354 mAh

How can this be normal? (I don't understand the tech side of batteries)

- I normally land with 30% battery life stiil available
- The batteries have never gone below 17% before I charge them

I use the standard DJI charging hub to charge the two batteries together + the remote controller.

I remove the batteries from the charging hub once the green lights have stopped flashing.

I don't understand this, is it normal, am I doing something wrong?

Thank you for your advice in this matter.

 

[aviscomi]

These batteries are Intelligent Batteries and will begin to discharge after a set # of days, see excerpt from manual below:

 

[Dronason]

So the question is how long between you charge a battery and you see the capacity in the Go4 app?
If it is less than an hour, it is abnormal. If it is more than a week, then it could the automatic discharge system of the battery.

 

[Mark Csabai]

Thanks for the replies.

Here's a screenshot of my Go4 App (the mAh on this battery is after only two charges) So, that is a loss of 122 mAh in two charges.

It's normally directly after every charge that I notice a drop in the Go4 app.

The time could be anywhere between twenty minutes and an hour.

For example, I will charge the battery that is showing 1382 mAh, and after the charge it will show 1360 mAh, the next charge will only go to 1345 mAh and so on.

The thing is, I still get about nine to eleven minutes flight time.

So, I'm no sure what's going on.

DJI have asked me to send them a screenshot, which will be my next stop.

 

[aviscomi]

You need to also add temperature to the equation

 

[speedsiao]

i am facing the same problem now, my battery total capacity keep going down

 

[Scobo]

Have you guys tried measuring the actual mah going into the battery ?
I have one of these .... Usb Voltage Current Tester Volt Current Doctor Charger Capacity Tester Power Bank Meter Keweisi Kws V20 Test Ammeter Voltmeter Usb Detector Rechargeable Batteries Batteries From Gh8520, $2.67| Dhgate.Com
It gives the total mah after charging.
Just wondering if it's the app giving incorrect readings ??

 

[The Editor]

For those of you new to DJI 'Smart' batteries this is normal behaviour.
All lipo packs loose capacity over time whether you use them or not. The internal resistance of the cells increase, they drop in their ability to give up a charge so readily and generally deteriorate with use.
This has been well known and managed by the RC model flying community for many years and with those years come experience of how to charge, maintain and look after lipo chemistry packs.
But then along came DJI and with it a new breed of RC flyer was born.
What DJI did with 'smart' packs was try to do a damage limitation exercise for individuals not versed in how to treat a lipo battery. Without the smart technology many would destroy a battery in a matter of days and not have a clue why.
Unfortunately, DJI's algorithms are a little over zealous in how they calculate loss of capacity within the pack and what you are seeing is those algorithms report a lower value almost every time you use the battery.
You will see a similar post over on Inspire Pilots (with a similar reply from myself) together with how we managed/mitigated the loss. I Want My mah Back!
Unfortunately, the Spark packs are sealed and therefore not easy (or even worthwhile) expending the effort to get to the individual cells. They are also relatively cheap packs so treat them as what they are which is consumables.

 

[Scobo]

Just recharged my battery and monitored it with my usb voltage meter. This is the 27th time I've charged it.

There was 12% left before I charged it, the app stated 150mah remaining and total capacity 1336mah.

After the charge completed, the voltage meter showed exactly 1500mah had been put into the battery.

Add the 150mah the battery had left and you have 1650mah.
The app however said 100% and 1325mah remaining with a total capacity of 1342mah.

So I wouldn't worry too much about what the app is telling you.