Balance plug for Mavic pack

[Danny-B-]

So you're not disconnecting it at all just spliced into the wires? Can you post a pic?

 

[everBit]

Yes, just connecting to cross-board using small Arduino clips or by soldering to nickel plates.
Cells connection are marked there as follows
Cell1 = B1-, B1+
Cell2 = B2-, B2+
Cell3 = B3-, B3+

Use lab power supply with a settings within 3.5 to 4.3v depending of cells voltages level and current about 0.3A
Be careful while working with lithium cells especially avoid touching any two nickel plates with metal instruments, it could cause short-circuit and damages.

 

[t0m541]

Bumping an old thread here I think, but reading through it there is some really good information and tips.
The reason I'm posting is that I recently bought an MP1 with 3 batteries, these all seem to be charging ok, for now anyway.
I also just bought a fly more pack, it was brand new, I'm assuming to the seller, everything still in wrappers, apart from the 2 batteries.
These I put on the charge cube and got nothing but the red led of doom.
Pressing the button on the battery did nothing.
So after doing a bit of research, I then plugged in the charger lead direct into the battery and left them for 12hrs on charge, thought maybe deep hibernation mode.
Still nothing, pressing the on button got no response.
So I dug a bit deeper and done some more reading and video watching, mainly people busting battery cases to get the things apart.
What I noticed was that the 2 main power cables from the battery board ran up inside the front cover of the case.
So I drilled a small hole in each corner where the case curved and sure enough, there was the red and black cables.
So using a multi-meter, I probed the cables and found a low voltage was there which told me that they connected to the battery cells.
So using 2 sewing needles as connectors I used the output on my balance charger to supply power to these cables.
Charger set to 3s at 0.5A and left it to slowly build up to 11.4v, took about 90 minutes.
I then re-checked using the meter and found, 11.38v.
I then pressed the on button and the battery scrolled the led's and sat at 3, so I plugged it into the DJi charger and it scrolled the led's again with 3 solid lit and No.4 blinking
I repeated the above with the second battery and got the same results.
However....after 12hrs of being on charge, the led's on both have dropped to 2 solid and 3rd one blinking.
Putting the battery on the drone does nothing.
I can switch the batteries on and off with the power button, but don't appear to be taking a charge from the DJi power supply and putting them on the 4 way, after some green blinking led, it goes solid red.
What I am thinking is that either the cells are out of balance so the internal board won't let it charge...or that the chipset has the perm fail fault flag.
So, I'm going to open the cases up and do the balance charge lead mod from the OP of this thread, and while I have it in bit I'm also going to plug into the BMS chipset and see if there are any fault flags and erase them.
I'll post back here as and when I make any progress with what I find, it might be a while as shipping is a bit slow for stuff to arrive etc.
Oh and Hi from a new member..

 

[t0m541]

Hi and here is the update on my battery experiments.
As I previously posted, the battery programmer I purchased finally arrived.
I downloaded the software from Texas Instruments who make the BMS chip only to find that whilst the software recognised the programmer it didn't cover the chip on the board.
So after a bit of research I found a link to the correct software version, as these batteries are now 6 years old, but the software didn't like the programmer as the firmware was too new.
So I bought another one that was a clone of the Ti one.
That arrived today, this one worked straight away with the older software.
So after a bit of careful soldering of wires onto the pinouts on the board and test and trial to establish what firmware was on the BMS chip, I managed to read the errors and found a permanent fail flag for battery voltage,(undervolt).
Carefully followed a video on how to reset the flag and put the battery on charge.
First on the charger lead plug, which charged it to 3/4 then put the battery onto the charging cube which then balance charged it to fully charged.
So that's one battery fixed, now to crack open the second battery and repeat the process.
I did try balance charging the battery using a balance plug prior to the reprogram, but the balance charger said the battery was fully charged.
If anyone wants links to parts used/software etc I can post them

 

[lee82gx]

Hi and here is the update on my battery experiments.
As I previously posted, the battery programmer I purchased finally arrived.
I downloaded the software from Texas Instruments who make the BMS chip only to find that whilst the software recognised the programmer it didn't cover the chip on the board.
So after a bit of research I found a link to the correct software version, as these batteries are now 6 years old, but the software didn't like the programmer as the firmware was too new.
So I bought another one that was a clone of the Ti one.
That arrived today, this one worked straight away with the older software.
So after a bit of careful soldering of wires onto the pinouts on the board and test and trial to establish what firmware was on the BMS chip, I managed to read the errors and found a permanent fail flag for battery voltage,(undervolt).
Carefully followed a video on how to reset the flag and put the battery on charge.
First on the charger lead plug, which charged it to 3/4 then put the battery onto the charging cube which then balance charged it to fully charged.
So that's one battery fixed, now to crack open the second battery and repeat the process.
I did try balance charging the battery using a balance plug prior to the reprogram, but the balance charger said the battery was fully charged.
If anyone wants links to parts used/software etc I can post them

Hi, and welcome...Thanks for your teaching. Yes, I'd very much be interested to have the parts and used and the SW. can you link them out?

 

[t0m541]

Hi, and welcome...Thanks for your teaching. Yes, I'd very much be interested to have the parts and used and the SW. can you link them out?

Here are the links to software https://www.ti.com/tool/BQEVSW, and hardware Battery Metering Chip Programmer UAV Battery Debugger Fit EV2400 EV2300 For TI#Z | eBay and video