[Sticky] How To Reset And Reprogram BQ304XX Chip Designed For 4.35V LIHV Cells To Work With 4.2V Cells
As far as i remember there was a topic here in the forum where a user was trying to replace LIHV 4.35v cells with standart 4.2v cells on a BQ30XXX chip and the Stage Of Charge was reported wrong which is normal since the discharge curve and chemical characteristics of the cells were different. The purpose of this tutorial will be to show users how this problem can be solved. It requires chip dataflash reprograming via additional hardware (EV2300 adapter) and additional software BQEvsw. There are a few main reasons why we can’t replace 4.35v cells with 4.2v.
- 4.2v cells will die very fast due to overcharging since they are designed to be charged to 4.2v maximum.
- Most of the times LIHV 4.35v cells will have a high discharge cut off voltage that is written in the firmware (EMF). The chip will consider the battery as empty when voltages of cells reach around 3.5-3.4v since discharging further will result in a very unstable and fast voltage drop. A normal 4.2v cell will not be able to deliver it’s full potential until 3.5-3.4v and it needs to be discharged to at least 3.1-3.0v.
- 4.35v LIHV cells are very hard to find and are very expensive.
So it should be clear by now why dataflash reprograming needs to take place. And before we even start I will post the original cells discharge curve so it can be compared to new cells discharge curve that I will use so you can see the difference.
The original cells were LGABC11865
The new replacement cells are LGGBH261865
STEP 1 Analyzing
We start with the initial first read of the battery with NLBA. We can see that it’s still unlocked and working fine but FCC has dropped below 50% which is normal considering that the cells have 236 cycles. We can also see that the chip is detected as BQ30421 which is correct. The Charging Voltage is 13050mv and the battery is 3s 2p so if we do the simple math ( 13050mv ÷ 3s = 4350mv).
STEP 2 Unsealing the chip so dataflash can be read and edited
Probably the most important step since if the chip is not unsealed reading and editing dataflash content is impossible! NLBA handles the unsealing process gracefully within a few seconds. No problems at all.
- To verify that the chip is sealed press READ CHIP INFO button.
- To Unseal press UNSEAL/BOOT button.
- To verify that chip is unsealed press READ CHIP INFO button again.
- DO NOT press END RESET button or the chip will be sealed again. Just disconnect the battery from NLBA and connect it to EV2300.
Step 3 Reprograming the dataflash using EV2300 & BQEvsw
So the battery is already transferred and connected EV2300 & BQEvsw.
We press the refresh button so initial dynamic data can be read.
Next we press DATA FLASH button followed by READ ALL button and this will result in displaying the whole dataflash content.
On PAGE 1 change the following values.
Remaining Cap Alarm = 10% of Desing Capacity
Manufacture Date = Current Date in hex
Cycle Count = 0
Design Capacity = Your new cells capacity
Full Charge Capacity = Design Capacity
Charging Voltage = 12600 ( 3S 2P BATTERY)
On PAGE 2 change the following values.
Safety Voltage = 12900
Emf = 3500
On PAGE 3 change the following values.
Vcell Unbalance Threshold – this is optional, it’s the cells imbalance value that will cause the chip to lock if greater then programed. In this case it’s 300mv which is a little low so it will be increased to 500mv.
Vmax Charge Voltage = 4260
Voff Charge Voltage = 4260
Von Charge Voltage = 4250
On PAGE 4 change the following values.
CCCV Charging Voltage = 12600
CCCV Over Voltage = 4250
CCCV Over Voltage Reset = 4150
CCCV Chg Voltage Cold = 12600
CCCV Chg Voltage Hot = 12600
Pulse Chg Voltage Cold = 12600
Pulse Chg Voltage Hot = 12600
On PAGE 5 change the following values.
Cccv Charge Volt cool warm = 12600
Pulse Charge Volt Cool Warm= 12600
Hot Charge Voltage = 12600
Hot Charge Voltage 2 = 4200
Weak FC Voltage = 4200
Sprint Max Chg Volt = 12600
Intvl Chg Min Chg Voltage = 12600
So we are done with dataflash reprograming. We just need to press WRITE ALL button to save all the settings. After we save the settings we can transfer the battery back to NLBA so we can check all the results.
Step 4 FINAL RESULT
So as we can see all the changes we have made are reflected in the dynamic & static data already.
The dataflash has been reprogrammed properly and the battery will work normally with 4.2v cells.
but I have no way to get bqEVSW for bq30421 / 3, like some other chips previously available for download on ti.com
would be very grateful for the opportunity to get this software.
но у меня нет возможности получить bqEVSW для bq30421/3, как и некоторых других чипов, ранее доступных для скачивания на ti.com
был бы весма благодарен за возможность получить данное програмное обеспечение.
Thanks for good tutorial, Can you share your BQEvsw version ?
how to download EV2400 software
Can someone tell me where to find this software
EV2300 & BQEvsw.