Quantcast
Channel: Power management forum - Recent Threads
Viewing all articles
Browse latest Browse all 35901

BQ78350-R1: BQ78350 SOC does not reach 0% at system shutoff voltage

$
0
0

Part Number:BQ78350-R1

I have configured the gauge with fixed EDV points
    EDV0 = 3371
    EDV1 = 3396
    EDV2 = 3425

My battery packs have a design capacity of 2600mAh at 4.2V. I am only charging to 4.1V so I see an initial reduction in the capacity to around 2350mAh after the learning cycle.

The SOC gets to 2-3% when the system shutoff occurs. I have attached logs from the system.


I would like for my gauge to hit 0% SOC, possibly occurring before the system shutoff point.

For this I tried to configure the reserve capacity as 5% of the design capacity (2600mAh * 0.05 = 130mAh). When I did this I initially noticed that the learned FCC, upon reset, was reduced by 130. Then when I started the test it reported a higher capacity until a learning cycle occurred.
I still do not get the SOC to report 0% with the reserve set as I intended. The learned FCC was reduced at this point from ~2340 to ~2140mAh. Do you think that the battery packs are exhibiting a non-recoverable loss in capacity at this point? I have completed ~20 charge/discharge cycles. The initial cycles seemed to go from 4100mV to ~2800mV per cell. Now the discharge goes from 4100mV to 3334mV before shutting off.

How do I configure such that the end of discharge reaches 0% SOC?

Since I am using a fixed EDV am I going to run into issues as the pack ages and the capacity is reduced? Will the EDV points need to be updated or changed? Is this handled in a CEDV config?

Zip file includes:

1. Earlier discharge
2. Current discharge (has  reserve capacity of 130mAh included)

3. Config (.gg.csv)

/cfs-file/__key/communityserver-discussions-components-files/180/20180712_5F00_memorydump_5F00_and_5F00_Logs.zip

Thanks,

John


Viewing all articles
Browse latest Browse all 35901

Trending Articles



<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>