Battery mod thread

Jspain · Dec 11, 2019

hii, good first thank the forum accept me, I wonder if the battery Sony Konion US18650VTC6 3120mAh 3.6V 30A could serve to replace the original, chers!

yamigos · Dec 11, 2019

Jspain said:
hii, good first thank the forum accept me, I wonder if the battery Sony Konion US18650VTC6 3120mAh 3.6V 30A could serve to replace the original, chers!

Already tested. This gives +5 minutes

Justinswidebody · Dec 11, 2019

aeropic said:
[QUOTE="Justinswidebody, hi, this is by far one of the most interesting thread on Mavic Mini ! Thanks admins for having accepted me.
I'm new to MM and still have to wait Christmas to get the mini ?.
However, I'm not new neither to rc nor to electronics...
I would like to first understand what are the functions implemented in the battery Bms ? Can we charge the batt with an external smart charger adapted to liion ?
I understand from the pinout drawing that the middle junction of the 2S cells is not accessible ? Is it ?
Do you think the 2 data lines are I2C or SPI data and clock lines ? If yes could we spy the bus to reverse ingeeneer the trafic ? The goal being to get rid of the stock BMS coding a kind of stub on a cheap microcontroler....
Well it's good to dream ?

The bms has a smbus with i2c giving it a SDA and SCL for data ports. I have no clue how to reverse engineer this. Maybe you could help out?

Marcuchinonis · Dec 11, 2019

yamigos said:
For any batteries. You can change 18650 to vtc6 or others if power is maintained on bms. Its easy

Connecting another battery 2s in parallel while changing cells?

Marcuchinonis · Dec 13, 2019

Any new test for this weekend?

Justinswidebody · Dec 13, 2019

Marcuchinonis said:
Any new test for this weekend?

Trying to think of new ideas for more flight time

aeropic · Dec 13, 2019

Justinswidebody said:
The bms has a smbus with i2c giving it a SDA and SCL for data ports. I have no clue how to reverse engineer this. Maybe you could help out?

I don't know if it will do the job but connecting a logic analyser could help to sniff the bus... To to this I need to buid a kind of male/female wire to extract the battery (I don't want (yet) to open the bird to solder a connector on the bus !)

Justinswidebody · Dec 13, 2019

aeropic said:
I don't know if it will do the job but connecting a logic analyser could help to sniff the bus... To to this I need to buid a kind of male/female wire to extract the battery (I don't want (yet) to open the bird to solder a connector on the bus !)

You wouldn't have to solder or open the bird. You could make tabs that fit over the pins that the battery plugs into.

yamigos · Dec 14, 2019

Marcuchinonis said:
Connecting another battery 2s in parallel while changing cells?

Yes. And first you need charge all batteries to full(4.2v)

YellowJacket · Dec 14, 2019

WithTheBirds said:
Even better- why not a solar panel that works in the dark?

Can you imagine the solar technology being advanced to provide significantly higher efficiency and it not being implemented? You would have a better imagination than most.

Can you imagine having to ascend above the clouds to recharge on your flight home ?

YellowJacket · Dec 14, 2019

Justinswidebody said:
Made some new batteries to make things look more clean... So far my best time is 37:07....

How to did you remove the battery door?

WithTheBirds · Dec 14, 2019

YellowJacket said:
Can you imagine having to ascend above the clouds to recharge on your flight home ?

No

Justinswidebody · Dec 14, 2019

YellowJacket said:
How to did you remove the battery door?

It pulls out. I'll take pictures later

aeropic · Dec 14, 2019

Justinswidebody said:
You wouldn't have to solder or open the bird. You could make tabs that fit over the pins that the battery plugs into.

Thanks, I will try this... I didn't know there was room enough to insert some wires...

Justinswidebody · Dec 14, 2019

aeropic said:
Thanks, I will try this... I didn't know there was room enough to insert some wires...

It wouldn't be wires , you would have to get some nickel strip like this. Breynet 3M 0.1 x 8 mm 18650 Pure Ni Plate Nickel Welding Strip Tape 3 M For 18650 Battery Spot Welder/Welding Breynet 3M 0.1 x 8 mm 18650 Pure Ni Plate Nickel Welding Strip Tape 3 M For 18650 Battery Spot Welder/Welding - - Amazon.com

Drill a hole that will allow for it to fit over the plug tab, and then use siccors to make it skinnier to not touch the other tabs

If you try to make it skinny first, when you drill it will just twist the nickel sheet

Justinswidebody · Dec 14, 2019

YellowJacket said:
How to did you remove the battery door?

YellowJacket · Dec 14, 2019

can i pull the door off by hand without removing screws and the hard top?

Justinswidebody · Dec 14, 2019

YellowJacket said:
can i pull the door off by hand without removing screws and the hard top?

You probably could, but I don't think you would get the door back on without undoing screws

aeropic · Dec 14, 2019

Justinswidebody said:
It wouldn't be wires , you would have to get some nickel strip like this. Breynet 3M 0.1 x 8 mm 18650 Pure Ni Plate Nickel Welding Strip Tape 3 M For 18650 Battery Spot Welder/Welding Breynet 3M 0.1 x 8 mm 18650 Pure Ni Plate Nickel Welding Strip Tape 3 M For 18650 Battery Spot Welder/Welding - - Amazon.com

Drill a hole that will allow for it to fit over the plug tab, and then use siccors to make it skinnier to not touch the other tabs

If you try to make it skinny first, when you drill it will just twist the nickel sheet

Thanks, i get it now !

Marcuchinonis · Dec 14, 2019

Anybody knows the + and - pins from bird battery connection? I’m gonna make a clip for test with dual battery. Do you think MM can fly with extra 100gr?