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Mavic Mini BatMan

aeropic

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Hello,
I designed this little gadget in order to manage the batteries without the need to place them inside the MM body.
BatMan is a simple way to manage the state of charge and different parameters of your DJI Mavic Mini Intelligent Battery.
In a future version, I may add the capability to discharge the batt for hibernation down to 60% of charge.
The battery Manager displays the following parameters:

  • Full charge capacity
  • actual capacity
  • percentage of charge
  • total voltage
  • each cell voltage
  • number of cycles (charge/discharge)
  • charge/discharge current
  • date of manufacturing
  • name of the battery
everything you need to build one : Mavic Mini BatMan by aeropic
see it in action here :
 

brett8883

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Hello,
I designed this little gadget in order to manage the batteries without the need to place them inside the MM body.
BatMan is a simple way to manage the state of charge and different parameters of your DJI Mavic Mini Intelligent Battery.
In a future version, I may add the capability to discharge the batt for hibernation down to 60% of charge.
The battery Manager displays the following parameters:

  • Full charge capacity
  • actual capacity
  • percentage of charge
  • total voltage
  • each cell voltage
  • number of cycles (charge/discharge)
  • charge/discharge current
  • date of manufacturing
  • name of the battery
everything you need to build one : Mavic Mini BatMan by aeropic
see it in action here :
Very very impressive. 👏
 
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aeropic

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Very very impressive. 👏
Thanks, but not that complex, everything is ready to read from the BMS... The only complex part was to reverse engineer the I2C protocol and understand how the BMS chip is working !
 

everBit

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The only complex part was to reverse engineer the I2C protocol
Still not clear what to reverse-engineer in the provided list of parameters 🙄
  • Full charge capacity
  • actual capacity
  • percentage of charge
  • total voltage
  • each cell voltage
  • number of cycles (charge/discharge)
  • charge/discharge current
  • date of manufacturing
  • name of the battery
They are standard SBS v1.01 compatible, well documented and ready-to-read over battery SMBUS port.

What is really "sweet" and most interesting things for reversing in that battery these are the firmware and proprietary DJI-specific smbus registers.
 

aeropic

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Still not clear what to reverse-engineer in the provided list of parameters 🙄


They are standard SBS v1.01 compatible, well documented and ready-to-read over battery SMBUS port.

What is really "sweet" and most interesting things for reversing in that battery these are the firmware and proprietary DJI-specific smbus registers.
Well, I did not know this SBS 1.01 protocol and I started by a spy on the I2C bus, trying to find first the slave address and trying to de commutate the logs. Then somebody put me on track with the name of a nearly compatible BMS chip (BQ30z554) which was very helpful to understand the protocol...
This is what I call reverse engineering. This being said, I'm ready to learn, any new information would be appreciated ;-)

EDIT: thanks I found a SBS spec here : http://sbs-forum.org/specs/sbdat110.pdf
 

raulmavic

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Incredible !

An amazing gadget, but it would be wonderful if you can add the ability to put the batteries in storage mode.

R.
 
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aeropic

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Incredible !

An amazing gadget, but it would be wonderful if you can add the ability to put the batteries in storage mode.

R.
Thanks, adding the controlled discharge is really easy and is in my to do list! Stay tuned it will come ;-)
 
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Capt KO

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Thanks, adding the controlled discharge is really easy and is in my to do list! Stay tuned it will come ;-)
The discharge part could easily be done with a USB battery pack. The same one used for charging. Now you just need to make it smart enough to stop at approximately 50%.
Great idea, keep it up.
 

aeropic

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The discharge part could easily be done with a USB battery pack. The same one used for charging. Now you just need to make it smart enough to stop at approximately 50%.
Great idea, keep it up.
good idea, that would even save some energy ;-)
 
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