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Recelling a 18650 based battery pack

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DjiBattWorkshop
(@djibattworkshop)
Member Moderator

After connecting resistors apply 12v on top of the stack to get chip powered.

 

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Posted : 09/09/2021 1:39 pm
Kevin liked
Kevin
(@kevin)
Estimable Member Customer
Posted by: @torture
Posted by: @kevin

Can I connect dummy resistors instead of cells for the time being? If so what resistance values shall I use?

Yes you can 470Ω. 

Thanks

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Topic starter Posted : 09/09/2021 1:41 pm
Kevin
(@kevin)
Estimable Member Customer
Posted by: @djibattworkshop

After connecting resistors apply 12v on top of the stack to get chip powered.

 

I just did that but the BQEVSW software is giving the following error.

image

Is this due to incompatibility?

Thanks

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Topic starter Posted : 09/09/2021 1:43 pm
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

Make screenshot of the very first page to check main Sbs parameters.

 

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Posted : 09/09/2021 1:46 pm
Kevin
(@kevin)
Estimable Member Customer
Posted by: @djibattworkshop

Make screenshot of the very first page to check main Sbs parameters.

 

SBS, Flags and static data.

Capturea
Captureb
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Topic starter Posted : 09/09/2021 2:08 pm
DjiBattWorkshop
(@djibattworkshop)
Member Moderator
Posted by: @djibattworkshop

Unseal the chip using NLBA1, then reconnect battery to ev2400, Select v1.05 plugin, Go To DataFlash and Select "Gas Gauging" page.

There very first step is omitted, that's why you getting error.

DataFlash of this chip could not be read in Sealed condition.

 

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Posted : 09/09/2021 2:19 pm
Kevin
(@kevin)
Estimable Member Customer
Posted by: @djibattworkshop
Posted by: @djibattworkshop

Unseal the chip using NLBA1, then reconnect battery to ev2400, Select v1.05 plugin, Go To DataFlash and Select "Gas Gauging" page.

There very first step is omitted, that's why you getting error.

DataFlash of this chip could not be read in Sealed condition.

 

Apologies, it's unsealed now.

image
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Topic starter Posted : 09/09/2021 2:51 pm
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

Parameters decoded correctly.

What is capacity of new cells and what is cells configuration?

 

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Posted : 09/09/2021 4:46 pm
Kevin
(@kevin)
Estimable Member Customer

The news cells have a capacity of 2550mAh each and they are configured in 2Px3S configuration and therefore a total of 5100mAh

Thanks

 

 

 

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Topic starter Posted : 09/09/2021 6:16 pm
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

Then put in the Qmax1...4, QmaxPack value 5350mAh (5100 + 5%).

Put in the DeltaVoltage value 0mV.

Everytime you enter a new value press Enter button on keyboard to write it to eeprom.

Then Go to Pro tab and send this command

WriteWord 0x0041 to register 0x00. It will SoftReset and Seal the chip.

Then Go to SBS tab and refresh parameters. Paste updated screenshot to check changes.

 

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Posted : 09/09/2021 6:49 pm
Kevin liked
Kevin
(@kevin)
Estimable Member Customer
Posted by: @djibattworkshop

Then put in the Qmax1...4, QmaxPack value 5350mAh (5100 + 5%).

Put in the DeltaVoltage value 0mV.

Everytime you enter a new value press Enter button on keyboard to write it to eeprom.

Then Go to Pro tab and send this command

WriteWord 0x0041 to register 0x00. It will SoftReset and Seal the chip.

Then Go to SBS tab and refresh parameters. Paste updated screenshot to check changes.

 

Screenshots in order

Capture

 

Capture2

 

Capture3

 

Capture4

 

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Topic starter Posted : 10/09/2021 7:16 am
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

So FCC just changed from 1504 to 2416mAh. This is because impedance tables in chip eeprom left from previous worn cells. They should be reset to reflect impedance of new cells.

There are three ways to do it.

1. Make relearning cycle according to TI requirements. Full Charge -> Relax 2 hrs -> Full Discharge -> Relax 5 hrs -> Recharge to Full or to Storage Level. Chip should recalculate impedances after this.

2. Updating the Chemistry tables using bqEasy plugin. It will rewrite impedance tables, OCV curves tables, temp correction tables and OCV flat range to your specific cells. But it require v1.04 support. Using v1.05 could break something in dataflash if any of updated parameters have different layout.

3. Updating Ra-tables manually using Hex-editor or SMBUS commands.

 

 

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Posted : 10/09/2021 8:12 am
Kevin
(@kevin)
Estimable Member Customer
Posted by: @djibattworkshop

So FCC just changed from 1504 to 2416mAh. This is because impedance tables in chip eeprom left from previous worn cells. They should be reset to reflect impedance of new cells.

There are three ways to do it.

1. Make relearning cycle according to TI requirements. Full Charge -> Relax 2 hrs -> Full Discharge -> Relax 5 hrs -> Recharge to Full or to Storage Level. Chip should recalculate impedances after this.

2. Updating the Chemistry tables using bqEasy plugin. It will rewrite impedance tables, OCV curves tables, temp correction tables and OCV flat range to your specific cells. But it require v1.04 support. Using v1.05 could break something in dataflash if any of updated parameters have different layout.

3. Updating Ra-tables manually using Hex-editor or SMBUS commands.

 

 

Thanks!

 

I think I will use method 1 once I receive and attach the new cells. 

 

I'll keep you informed.

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Topic starter Posted : 10/09/2021 8:49 am
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

By the way what is model of new cells planned to use, is it BAK as you mentioned before?

And what cells were originally installed?

Also check presently preprogrammed chemistry profile by running these commands

WW 00 0008

RW 00

 

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Posted : 10/09/2021 9:45 am
torture
(@torture)
Member Moderator

@kevin 

The Cycle Count must also be reset after battery recelling.

At the moment it's 1141.

Also not a bad idea to change the manufacture date since the battery will be considered as new.

Both values can be found on the SBS Configuration tab of BQEvsw.

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Posted : 10/09/2021 3:26 pm
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