Dear Forum,
We recently got a BQ40z60EVM - 578, which is a charger and gauge board for use with Li-ion batteries with 2s-4s configuration.
I am trying to test using 2 cells in series. As instructed in the User's guide, I connected the negative of cell 1 to 1N, then positive of cell 1 and negative of cell 2 on 1P, and positive of cell 2 to 2P, and two resistors of 1KOhm between 2P-3P and 3P-4P.
Now, I connect a load of about 200 Ohms between the VSYS and PGND (I tried with a 10KOhm resistor as well), and a Power Supply between VAC and PGND, with voltage set to about 10.8 V, which is higher than the final charge voltage of two cells combined (4.2V + 4.2V).
Then I connect a EV2400 adapter using the SMBUS port, to a PC with bqStudio installed. When I launch bqStudio, I have to press the Wake-up button for bqStudio to recognise the gauge. Once it does, it is able to measure the voltage of the combined system which sits right now at about 7.3V (gauge reports 7267 mV). But gauge doesnt report any charge / discharge current nor does it report SOC etc.
Also, the gauge goes to a sleep mode, in about 30 seconds. When I try to wake it up again by pressing the wake-up button, it wakes up for 30 seconds, and then sleeps again. In the sleep mode none of the registers update and I cannot communicate with the gauge.
I learned that the BQ40z60 is pre-set for a 3 cell configuration and the "Settings" -> "Configuration" -> "DA Configuration" needs the values of CC0 and CC1, which I try to set using bqStudio and it gives an error called "operation failed because initial read of all data flash failed". I also tried unsealing the gauge, it required a code, which seemed correct in the textbox - 36720414 and FFFFFFFF for unsealing with full access, but these commands also, didnt work.
My jumper settings are as follows:
SERIES CELL SELECT (J4) - 2S
J2 - SYSPRES and ALERT
J7 - SYSPRES (in place)
I tried to use the LED DISPLAY functionality, but that didnt work as well.
Am I missing some startup step ? Any guidance in this regards would be appreciated.
Thanks and Regards
Chintan Pathak
Research Scholar,
University of Washington