BATTERY NOT 100%

[360 Guy]

On my Mini 2, I have all batteries (3) charged to 100% or four (4) lights.
When battery(s) are installed and ready to fly, I notice that the IPad screen says that I have 89% battery life to fly.
I am not killing time untill take off, only making sure that I have at least 14 sats and no I m not charging IPad thru controller, that is turned off.
From time of firing up everything and ready to fly, I might have spent 5 minutes total and I'm in the air.
My question is: Why is my screen showing 89-88% charge before take off when batteries are charged 100%?

Thx for your input.

 

[FLDave]

I suppose because they are charged only to 88-89% of their full charge capacity when the batteries were new.
Charging stops when batteries are charged to their current capacity, not to their original maximum capacity.
How old are your batteries? How many times have they been charged? How long have they been used?

 

[karlblessing]

When you charge them to 100%, is there more than a day between that and when you fly? If so the batteries do an auto self discharge after some time to help protect the battery health, it usually starts after a day or two.

It can also be like Dave said, after a while the batteries can't hold the same capacity they once held. If you check the battery information in the dji fly app, it should show the number of charges that battery has had, and they're usually rated for about 500 cycles.

 

[360 Guy]

karlblessing, thanks, that is probably the answer, maybe three or more days between flights.​

Dave is wrong on the charge limit, that is true for nicad batteries but not lithium.
Nicads have a memory, sorry Dave.

 

[GadgetGuy]

On my Mini 2, I have all batteries (3) charged to 100% or four (4) lights.

My question is: Why is my screen showing 89-88% charge before take off when batteries are charged 100%?

Because 4 lights only indicates >75%, not necessarily 100%, unless you just fully topped them off within less than 24 hours. After 24 hours, they auto discharge to 96% and start declining from there after 3-10 days, depending upon the battery model.

You also cannot top off a 96% charged battery unless you first manually discharge it to 95% or below by using it to power something.

To start with a 100% charged battery for flight, use one battery for setting up everything, and then swap out for a 100% battery for launching. Battery swaps boot up into a ready state, including HP acquisition, within 15-30 seconds, instead of several minutes.

 

[Ex Coelis]

karlblessing, thanks, that is probably the answer, maybe three or more days between flights.​

Dave is wrong on the charge limit, that is true for nicad batteries but not lithium.
Nicads have a memory, sorry Dave.

He’s not referring to NiCad memory effect. He’s explaining “capacity”. Rechargeables diminish in capacity with age and cycles.

 

[karlblessing]

He’s not referring to NiCad memory effect. He’s explaining “capacity”. Rechargeables diminish in capacity with age and cycles.

Like that iPhone 6s that people kept after several years that can't hold a charge worth a **** anymore.

 

[Ex Coelis]

Like that iPhone 6s that people kept after several years that can't hold a charge worth a **** anymore.

Yup, I still occasionally use an old 7 at 75% for tunes. My 13 is at 96% after 11 months….

 

[GadgetGuy]

He’s not referring to NiCad memory effect. He’s explaining “capacity”. Rechargeables diminish in capacity with age and cycles.

AirData also shows the percentage remaining of the new full 100% battery capacity, which is the true battery percentage when DJI will still be displaying 100% each time the battery is fully charged.

 

[Ex Coelis]

AirData also shows the percentage remaining of the new full 100% battery capacity, which is the true battery percentage when DJI will still be displaying 100% each time the battery is fully charged.

Yes; DJI shows 100% of the remaining capacity, ie 100% of its current ability to accept a charge.