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Mavic Mini BatMan V2 ( a battery manager)

aeropic

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BatMan V2 is coming...

As some of you requested, I added a battery hibernation function to empty the batt down to 65% of charge.

In order to keep the device as "green" as possible, the load is either a smartphone or a powerbank and the extra energy is transferred to the connected device
1f609.png


The modification of the first version is quite simple as the 5V was already generated by a bulk down converter. This DC is able to push several amperes and has an ENABLE pin that can be used to suicide at the end of the discharge!

See it in action :

I will publish the circuit once documented...
 
Excellent project
Do you think it will be possible, with the same SBS protocol, to use a non-DJI battery and simulate an original battery?
Maybe with more Amp on board .... ;)
This would be useful for above all
for other Mavic models such as the AIR
 
Excellent project
Do you think it will be possible, with the same SBS protocol, to use a non-DJI battery and simulate an original battery?
Maybe with more Amp on board .... ;)
This would be useful for above all
for other Mavic models such as the AIR
I'm not sure it would work... Part of the exchanges between the ESC board and the BMS over the SBS protocol are manufacturer fields that are not diocumented...
 
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In the commet on youtube he wrote : "Its self made board with modified firmware,you can change the batteries without lock up "
 
I've read you have spoofed i2c communication on the BMS between battery and drone.
It's possible to intercept the firmware while uploading on the battery during update process ?
Probably , original BMS board have a protection that self-broke something while no voltage is applied but is not a fw capabilities, is like a fuse
 
the BMS has some internal FET that act like fuses if it detects an undervoltage on a cell or an unblalenced batt or overcurrent it opens the FETs permanently.
Those FET can be reset using an encrypted protocol... (SHA algo) but the key is not public.
I'm afraid the firmware will follow the same protection logic ;-(
 
In your opinion, could you simulate the messages that the bms board sends to the drone with i2c protocol ?
They could be simulated with an external programmable card, without using a real BMS.

What I mean is that if you can read the messages via i2c from the battery, you can also send them to the drone, right ?
 
In your opinion, could you simulate the messages that the bms board sends to the drone with i2c protocol ?
They could be simulated with an external programmable card, without using a real BMS.

What I mean is that if you can read the messages via i2c from the battery, you can also send them to the drone, right ?
It was my intention to do so:
- boot the MM on the original DJI batt BMS (only the SMbus/I2C part)
- unplug the BMS SMBus lines
- plug a homemade "BMSlight" board emulating the exchanges

However this is somewhat more complex that expected.
- the protocol is SMBus not I2C, and some checksum bytes shall be added
- the board shall act as a slave (not intiating the exchanges) and by now, I cannot succeed programing an ESP8266 board in this mode

Still in my to do list ;-)
 
Great !!!!
This would be a really great thing to be able to use batteries that are not DJI and to be able to use all the new types of 18650 cells that will come out.
Currently I don't own an MM but this project is making me think very seriously.
In the past I have done some projects with arduino and similar boards, if you want and you think it could be useful let me know.
Unfortunately I don't have an i2c analyzer but I have found them from 80 € and up.
I also own a 3d printer ;)
 
Great !!!!
This would be a really great thing to be able to use batteries that are not DJI and to be able to use all the new types of 18650 cells that will come out.
Vadda, have a look to this ;-)
 
Vadda, have a look to this ;-)
Where can I buy a bob
 
Vadda, have a look to this ;-)
this link is not active anymore,do you have something else?
 
this link is not active anymore,do you have something else?
Thiniverse sucks... Here is the new link. Please go to the file section and download the docx file!
 
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thank you
i tried to change cells with highest capacity,unfortunately i did the batt update without knowing the issue,and ended up with a bricked bms.I have read the entire forum about this matter but could not fix it.
Any ideas ?
Thanks in advance,
George.
 

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