Part Number:BQ27Z561EVM-011
Hello,
I am a newbie in battery gauge domain. I need to perform a learning cycle on a NCR18650 Lithium Ion battery by BQ27Z561EVM-011 battery gauge and BQ27GDK000EVM kit. I have already done the current and voltage calibration and uploaded the ChemID.
Now I meet a problem that the learning procedure takes too much time in my case. According to the video guide for learning cycle (https://training.ti.com/how-perform-successful-learning-cycle-gauges?keyMatch=LEARNING%20CYCLE%20VIDEO&tisearch=Search-EN-Everything), in order to accomplish a successful learning cycle, the following steps should be performed:
Step 1). Discharge battery by C/5 rate (in theory it takes 5 hrs);
Step 2). Relax battery for a period of time (according to the guide https://e2e.ti.com/blogs_/archives/b/fullycharged/archive/2016/03/02/how-to-run-a-learning-cycle, it should take at least 5 hrs);
Step 3). Charge the battery by C/2 rate (by the data sheet of NCR18650B, it should take around 4 hrs);
Step 4). Relax battery for a period of time (according to the guide https://e2e.ti.com/blogs_/archives/b/fullycharged/archive/2016/03/02/how-to-run-a-learning-cycle, it should take at least 2 hrs);
Step 5). Discharge battery by C/5 rate (in theory it takes 5 hrs).
Step 6). Relax battery for a period of time (according to the guide https://e2e.ti.com/blogs_/archives/b/fullycharged/archive/2016/03/02/how-to-run-a-learning-cycle, it should take at least 5 hrs).
If the procedure above is correct, the total time of a full learning cycle should be 5 + 5 + 4 + 2 + 5 + 5 = 26 hrs.
In the post https://e2e.ti.com/support/power-management/f/196/t/461819?AutoCycle-BQStudio, it reads that "the Auto cycle feature is not supported using the EV2400". Since I am currently using the on-board EV2400 of BQ27Z561EVM-011, the only choice for me is to perform the learning cycle manually. While normally, no one can keep monitoring the learning cycle for 26 hrs. By this reason, I come out several solutions for my case:
Solution 1). Decrease the time cost of each step listed above, like discharge by a higher rate, for example C/2 and let the battery relax less time, e.g. 2 hours for each step of relaxing. I know this solution looks crazy and probably not feasible. I still want to ensure if increasing discharge rate and decreasing relax time is feasible for the learning cycle. Let's call it Question 1).
Solution 2). Increase the relax time of some relax step in order to separate the procedure into several days, for example:
Day1: Discharge battery by C/5; relax until next morning;
Day2: Charge the battery by C/2; relax until next morning;
Day3: Discharge battery by C/5; relax until next morning.
By this approach, the problem could be solved. While I still have some questions (following previous index):
Question 2): Will the result of learning cycle be inflicted by increasing the relax time?
Question 3). Can I turn off battery gauge and/or GDK during relaxing time?
Thanks for your patience to read my question.
Waiting for your reply sincerely,
Wenlong
