Dji smart battery replacement attempt

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hi every one, since am along some one else who may think that phantom 3 is still air worthy, and since not a lot of batteries are still available for this craft in market or if any is still there the quality or price maybe a concern so i tried to solve this by using our hobby avalable 4s lipo s or 18650 lithiums.
now first i tried to search the net or youtube for such done thing, i didnt find some one who fully did it...
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i wondered why.. when i stsrted it my self i understood that it is not a simple swap...
first i discovered that the phantom 3 batteries are not 4s lipo type but 4s lipo hv or lithium polymer high voltage , a family that charges not like lipo 4s from 14.8 to 16.8 but from 15.2 to 17.2 upon reading about both types they can replace each other so its not the problem...
. the major troubles come from the smart term... all dji phantom 3 batteries are smart batteries that control the 4s lipo hv and communicate with the aircraft from the very first second of power on ...
so only if some one can help in finding a way around this , the trouble can be solved and a battery replacement solution is possible
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i soldered an xt60 to the power in lines and tried a 3s and 4s regular lipo to start the phantom with no success some of the components of the aircraft turn on and it starts making an alarm....
i placed a twin extention to place a battery in parallel with the dji smart battery this time in the phantom and an external 4s lipo . every thing booted correctly and armed i test flew it once but the problem was the voltage display was givving 100% all time !!!! ???? i got only 15 min of flight from almost a 8A lipos connected( 4000 or so from dji smart battery and the 4A 4s lipo i plugged in'), i landed and checked the voltage since i didnt like this 100% full i found that both batteries are almost empty.
now the smart battery and aircraft communicate by 2 lines on battery that connects to 4 pin like spikes in the battery connection port of the p3 body. as i was tinkering with the dji smart battery i found that on the battery the 2 lines are marked sda scl ,which should be the communication protocol . if some one has a solution to this it is wonderfull to share it may also help with other dji family like the p4 or mavics maybe!!
either an idea of a solution to pass the battery checks and connect any lipo to p3 and fly it with time accounting in mind
or a better safe option on how to fly a combo of smart dji battery with other batteries and having a correct voltage level display .
i didnt have time to make a video so ill share some pics of the p3 and its modded battery
 
i found that on the battery the 2 lines are marked sda scl
Can you show a photo of this?
I'm asking because that's not correct - the protocol used is not I2C, so the names should not be SDA/SCL.
it may also help with other dji family like the p4 or mavics maybe
Only the Mavic Pro, I think. Other seem to use extended SBS protocol (over SMBus).

either an idea of a solution to pass the battery checks
Not that many ways to do that. There are actually two:
- discard the original board and simulate the protocol from MSP430 using a simple micro-controller board (pi/arduino)
- modify the original board so that PF is disabled and the BMS resets to new cells every time

For both ways, you can search for existing materials. Start here:
O-Gs Wiki - Ph3 Intel. Battery Diagram
 
Can you show a photo of this?
I'm asking because that's not correct - the protocol used is not I2C, so the names should not be SDA/SCL.

Only the Mavic Pro, I think. Other seem to use extended SBS protocol (over SMBus).


Not that many ways to do that. There are actually two:
- discard the original board and simulate the protocol from MSP430 using a simple micro-controller board (pi/arduino)
- modify the original board so that PF is disabled and the BMS resets to new cells every time

For both ways, you can search for existing materials. Start here:
O-Gs Wiki - Ph3 Intel. Battery Diagram
man ur a bible , i will do my homework i hope u stay tuned in for some support , with most appreciation in advance!
20221214_071852.jpg

this is the pic of a p3 dissembled smart battery plug where the sda, scl written on connectors, where the red and yellow wires connect, all p3 batteries i saw earlier are marked like that
 
at least some one has proven the concept!!
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but but but sadly he didnt leave a simple note just that he seems smart in Arduino!!
so whats next what should i do??
 
Last edited:
so whats next what should i do??
Arduino way - capture communication on the UART. You can then use Wireshark dissectors to look into them, and implement the packets on Arduino.

BMS modification - use any tool to connect to the SMBus interface of the BMS (ie. comm_sbs_bqctrl.py using RPI, or the GUI one using I2C stick, or BQ Evaluation Software if you have EV2300.
 
well i prefered to find a fully mature solution or test on this given that i dont have the time to dictate for this R&D project... ill still search even a partial thing done on this( suppose some code or notes or..) maybe put together , every one is welcome here to allow this to happen
 
to this point the proposed solution for a semi diy or semicustom replacement for a dji battery is to use a dji smart battery board connected to a pack to replace the original pack... i didnt find any other clue...
 
but pay attention as i did this mistake my self when disconnecting a smart battery board i advice to disconnect the battery first the solder or what so ever then reconnect!! i fried a board by a drop of soldercure that unintentionally spilled over an smd resistor maybe, the thing fried and never works now
 
I am interested in being able to provide power for testing a P3 when on the ground using the smart controller from an old battery, and providing the necessary voltage to stop the PF mode (then obviously clearing the flags via SM bus).
Does any one in the UK have a broken P3 battery that they would be willing to sell me cheaply to help in this task??
It would be much appreciated.
 
I am interested in being able to provide power for testing a P3 when on the ground using the smart controller from an old battery, and providing the necessary voltage to stop the PF mode (then obviously clearing the flags via SM bus).
Does any one in the UK have a broken P3 battery that they would be willing to sell me cheaply to help in this task??
It would be much appreciated.
what is this SMbus??? am still interested and searching on how to make an external battery a non dji thing work on the phantom3
 

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