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Battery mod thread

What’s the state of battery mods?

I was just thinking that a lightweight 450mah 2s lipo (which I have a few) would work well on mountains due to reduced weight and needing less thrust to stay in the air.

Does 3s work? I’ve seen the original Mavic pro run on 4s. That’d give more thrust at high altitude on a mountain without having to get some kind of custom prop

This works with any Lion battery, it is also possible to use the 3S with a simple circuit modification.
Write to the author in private messages to receive the board + chip.
 
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I have a Mavic Mini (bought in August 2020) and a dead battery (from the Fly More Combo).

I bought two 18650 battery cells and want to replace the ones in the dead battery.
I did not update the battery firmware since I bought the MM. Now I cannot read any information from this battery....

My question: do I even have a chance that the battery with the new cells will work?
I read through some of the pages in this long thread, but I have a hard time to find the right information for me - sorry!

Thanks for all hints!
 
Could not read by drone and app or by external SMBUS adapter?
Thank you, everBit - I don't even know, what a SMBUS adapter is. I could google it - but even if I would know, I am pretty sure nobody here, near Cusco, Peru has one :)

I have a Multimeter and a basic soldering iron. As well as two pairs of 18650 batteries. If I cannot do it with this "equipment", then I will bring the old battery to the recycling station (which doesn't exist either :) ).
 
You could Google for cp2112 adapter, it's quite chip at AliExpress. It could help you to detect whether battery could be revived or not.
Anyway as you mentioned you never updated it so it should be still with magic v100 firmware)
And if so, you could recell it with another good cells and try to charge then.
But first of all me recommend to check condition of present cells using multimeter which you already have.
Dissasemble it and measure each cells voltages. If they are more then 1.5V try to precharge them to 3.6V.
If they completely discharged to zero then they should be definitely replaced.
For drones batteries only high rated cells could be used. General use 18650 not suited for this applications.
Recommended cells are Samsung INR18650-25R, Sony VTC5, VTC6, Liittokala HG2 etc.
 
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Thank you, everBit - I don't even know, what a SMBUS adapter is. I could google it - but even if I would know, I am pretty sure nobody here, near Cusco, Peru has one :)

I have a Multimeter and a basic soldering iron. As well as two pairs of 18650 batteries. If I cannot do it with this "equipment", then I will bring the old battery to the recycling station (which doesn't exist either :) ).
When opening the battery and removing the cell, the BMS chip self protectrd itself to lock the BMS... In other words the BMS is bricked...
Unbricking it is possible but you would need spécial hardware and software equipment which is expensive...
 
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When opening the battery and removing the cell, the BMS chip self protectrd itself to lock the BMS... In other words the BMS is bricked...
Unbricking it is possible but you would need spécial hardware and software equipment which is expensive...
The BMS “protected itself” from what?
,
 
From dead cell, or unbalanced cells, or too low cell, or users intrusion !
Trust me those TI chips are very 'smart' when it comes to protection !
Yes, they are. I don’t need to trust you, have the application notes on a few of the TI battery monitor SOC- I thought DJI would have moved away from TI for the BMS by now, like they did with the speed controller solution.

My question remains.... what specific condition causes the lockout?
 
Yes, they are. I don’t need to trust you, have the application notes on a few of the TI battery monitor SOC- I thought DJI would have moved away from TI for the BMS by now, like they did with the speed controller solution.

My question remains.... what specific condition causes the lockout?
 
Search for BQ40Z307 or BQ40z80 datasheet. Then read chapter 4 permanent fail and you'll get the reasons for permanent lock such as 'safety cell undervoltage', 'overcurrent in charge or discharge', over temperature, Q max unbalance, cell balancing, capacity degradation,...
 
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Search for BQ40Z307 or BQ40z80 datasheet. Then read chapter 4 permanent fail and you'll get the reasons for permanent lock such as 'safety cell undervoltage', 'overcurrent in charge or discharge', over temperature, Q max unbalance, cell balancing, capacity degradation,...
Which device is used in the Mavic mini battery? Is it one of those two?

The fault conditions are well known and documented- no question there.

I thought you may have specific knowledge. We all can guess.

The reality probably is that the battery can’t be fixed by an end user once bricked even with hardware. The SOC will be locked in manufacture.
 
When opening the battery and removing the cell, the BMS chip self protectrd itself to lock the BMS... In other words the BMS is bricked...
If it would be 100% true then this thread will not even exist. Anyway it's all about "opening the battery", "removing the cells" and various forms of "user intrusion".
As it was discovered by Topic starter, Mini's batteries with stock v100 firmware are free from bricking features or these are significantly reduced. Same was confirmed by a lot of other pilots on the youtube and drone's forums.
And as @Emanaku mentioned, his battery was never updated, so it still has those magic features!).
Yes, "updating" sometimes is evil, especially when it comes to DJI products. All we know "anti-rollback" releases etc.
Which device is used in the Mavic mini battery? Is it one of those two?
Mini's uses bq9003 with bq40z307 firmware.
Search for BQ40Z307 or BQ40z80 datasheet.
Have you ever seen datasheet for bq40z307?)
From what me know it's NDA device and its documentation is not publicly available.
Anyway these two chips are different, as on hardware as well as on firmware levels.
bq40z80 has native Texas Instruments firmware while bq40z307 has specially designed TI/DJI firmware with respect for drone's applications. Permanent Failure features are different as well. DJI has its own settings which depends on the drone model and firmware revisions.
Due to flight safety concerns drones bms PF settings are significantly reduced or sometimes even removed to avoid any early bms shutoff midflight as battery cost incomparable with drone cost.
 
A bit off topic but I need help, I currently doubled the battery of my Mavic 2 Pro. I found the battery cannot be fully charge up, can anyone tell me which battery parameters will need to be changed, what shall be the new set value. I can access to parameter with CP2112.
 
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