dji mavic pro batteries issue

[jofer]

hello again, i think the two batteries are faulty.

i did 3 times with one of the batteries, the last time at the end it was with 6% battery: 3.23v 3.66v 3.77v 10.68v 33.5ºC, and few seconds after the drone shuts down. i recharged again the battery and the app gives me the same error.

the second battery i charged one time, discharged, charged again, and the problem continues, so i think its faulty too...

right now one of the batteries is:
99% 4.16v 4.03v 4.25v 12.41v 23.6ºC

and the other is:
91% 3.84V 3.97V 4.21V 12.03V 21ºC

when i charge the batteries, after they charge, they start blinking one light only, its the 2nd or the 3rd light. i dont remember wich.

any more advice to try to fix the batteries? or they are faulty and i need to buy new batteries?

thanks

 

[mnis]

hello again, i think the two batteries are faulty.

i did 3 times with one of the batteries, the last time at the end it was with 6% battery: 3.23v 3.66v 3.77v 10.68v 33.5ºC, and few seconds after the drone shuts down. i recharged again the battery and the app gives me the same error.

the second battery i charged one time, discharged, charged again, and the problem continues, so i think its faulty too...

right now one of the batteries is:
99% 4.16v 4.03v 4.25v 12.41v 23.6ºC

and the other is:
91% 3.84V 3.97V 4.21V 12.03V 21ºC

when i charge the batteries, after they charge, they start blinking one light only, its the 2nd or the 3rd light. i dont remember wich.

any more advice to try to fix the batteries? or they are faulty and i need to buy new batteries?

thanks

I see a positive change in cell differences. You could repeat the cycles until no improvement is achieved, and then decide. Maybe the tip about overwriting the firmware helps. There is nothing to lose, except the time required. You may eventually have to dispose of the defective batteries.

I would like to make a few more attempts, but already consider the purchase of new batteries.

Edit:
As an alternative to disposal, you can offer the defective batteries on eBay for sale. There are always hobbyists looking for broken batteries. You can then use the revenue for new batteries

 

[mnis]

I respect your opinion and your caution but my experience is a bit different. When you look at the current discharge(the amount of battery being used at any given moment) you’ll see something that may seem strange. The amount of current used to hover and fly slow is often more power than flying fast. Yes braking and accelerating quickly use up a good amount of current but probably not as much as you’d think. It turns out it’s more complicated than you’d think.

When in sport mode you can change your mini map into the “radar” attitude gauge thing. This will show you the % of the maximum current discharge you are currently using. There is a point on the gauge where it turns from green to blue. Right at this point it indicates most efficient use of power. If you are concerned about using up too much battery you can check this to know you aren’t over discharging the battery. You can also keep an eye on the RPMs on the remote. This is an average of all 4 motors and is a good indicator of the amount of current being used. Generally speaking the most efficient average motor speed is 650 or 6500 RPMs. This is for the Macic Pro I don’t know about the Mavic 2.

DJI did a good job of designing the Mavic to be very forgiving when it comes to this and the Mavic is actually much more powerful and much faster than the software allows. This doesn’t mean you should fly balls to the wall the whole time but I wouldn’t be overly worried about it. The Mavic will let you know if you are harming it before you can do any real damage. The easiest way to do that though in case you are wondering is to full sticks up and forward. It takes a ton of current to ascend at max speed and fly forward at max speed. Try to limit doing that I think you’ll be fine in sport mode.

I understand the relationships regarding engine speed and energy consumption. I also understand that it is possible in sports mode not to stress the batteries.

But if inexperienced Mavic pilots use the Sport mode, then the sticks go right to the max of the possible. Nobody will keep a watchful eye on rpm, currents or temperatures, it's all about the fun factor, and that puzzles me.

Some pilots reported after the crash that the Sport mode was active while the battery jumped out of the Mavic. Of course, in these cases, it could have been about badly maintained or old batteries.

Actually, I never needed sports mode, and would not recommend a newbie to use it. Even if you fly with relatively old batteries, you should not stress them.

It's nice that the Mavics are equipped with so many protection features, but not all unfortunate events can be prevented...

 

[mnis]

Yea the self-discharging is really just a fail-safe in case you forget to manually discharge them every once in awhile. I don’t think it was really meant to be relied on as an alternative to manual discharge.

Interesting you say this because on the Mavic 2 they removed the feature to change the standard 10 days to self-discharge. I have been wondering why so maybe it’s just best to leave it at 10 days. Thanks for the heads up!

Regarding the batteries:
I try to recharge my batteries in the evening before the day of the flight. If the flight can not be done the following day for some unpredictable reason, then it's not a big deal. My batteries are set to start the automatic discharge after 24 hours of full state. A short press of the button resets the internal timer of the battery. It gives me an extra 24 hours to easily fly later.

When I do so, I do not have to worry about my batteries lying around in a fully charged state for too long. Half of my batteries are almost two years old, and as far as I can tell, all the batteries are in good condition.

For me It is a pity that DJI has set this automatic discharge function to unchangeable 10 days for the new Mavics. There are many discussions about these unchangeable 10 days, and I think it's a badly chosen compromise from DJI.