StateofCharge reaching 120%, bq27510

Hi Joshua,

Have you completed a successful learning cycle on the device? If Qmax has not been updated, you may see incorrect values for SOC.

Best,
Justin

We have completed a successful learning cycle on the device, to no avail, we are still seeing 120% percent for the entire duration of the discharge. The battery dies as the fuel gauge is still informing the micro controller that it has 120 percent. The EV2300 however, and BQ programmer are able to determine the correct charge. Was there a change in the command from Firmware 1.11 to firmware 4.00 that could result in this problem?

Hi Joshua,

It appears that this error may be due to a register mapping difference between the firmware on bq27510-G3 and previous versions. If you are using a different firmware, you may not actually be reading what you are expecting to see as SOC. What you can do is to update the firmware and identify which version of gauge you are talking to and then use the correct register map.

Best,
Justin

We were able to identify a work around by changing the IDSEL register.  The cause of the problem is related to the fact that the bq evaluation software has not been properly updated for G3.  The bqeasy wizard incorrectly configures the chip for the "SOC1 Set" and "SOC1 Clear" because they are still using "mAh" instead of "%".  Additionally the parallel cells question causes this issue when set to "1" instead of "0".  Although that may be the intent, the question should have a drawing or additional information because I personally can interpret the question to mean 1 = 1 battery, or 0 means 1 battery (no batteries in parallel.

By having the IDSEL set to 1 (on) for the G3 firmware, it reads the wrong register, "Cell 0", for the battery charge, but uses "Cell 1" for the installed battery.  The mismatch results in the Fuel Gauge reporting the wrong value.

Example: Cell 0 was reading 1750 mAh, Cell 1 was reading 1698 mAh, the unit was using data from cell 1 but using the % from cell 0.

The BQEaSY needs to be updated to prevent additional issues, as well as figuring out why this configuration in the 27510-G3 results in it not using the correct Cell register for reporting the active battery.

We are using the current firmware, the problem is at least that the bq Gas Gauge Evaluation software for G3 has bugs in it. I would appreciate if your staff would help us with a work around, our production has been halted for almost 2 weeks because of this particular part.

Joshua,

taking your conversation offline. I have sent you a friend invite.

thanks

Onyx