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BQ78Z100: BQ78Z100 RSOC jump issue after a few months storage

Part Number: BQ78Z100
Other Parts Discussed in Thread: GPCCHEM

Hi 

The customer set the CHEM ID and full learning, after a few months storage the RSOC incorrect during charge and discharge.

Attached the GPCCHEM report and log data.

Chemistry ID selection tool, rev=2.53		
		
Configuration used in present fit:		
ProcessingType = 2		
NumCellSeries = 2		
ElapsedTimeColumn=2		
VoltageColumn = 7		
CurrentColumn = 8		
TemperatureColumn = 6		
		
Best chemical ID : 2195	Best chemical ID max. deviation, % : 1.08	
		
		
		
Summary of all IDs with max. DOD deviation below 3%		
		
Chem ID	max DOD error, %	Max R deviation, ratio
2195	1.08	2.85
2892	1.1	0.43
1302	1.1	2.49
1565	1.11	3.32
2489	1.17	2.58
2304	1.23	0.64
1944	1.25	4.96
584	1.27	0.37
468	1.3	1.15
2117	1.3	1.15
120	1.38	0.44
1763	1.43	2.48
3547	1.44	6.12
2289	1.51	0.32
1176	1.53	8.35
194	1.54	2.47
3721	1.55	5.64
1304	1.57	9
128	1.61	0.75
161	1.62	2.81
1124	1.62	2.81
1452	1.62	0.41
1328	1.63	0.74
1296	1.65	5.76
2290	1.66	3.11
5754	1.67	1.3
1221	1.67	2.05
1185	1.69	1.86
2022	1.69	1.75
1375	1.71	0.49
1344	1.72	0.49
3329	1.72	0.1
1362	1.72	0.48
2316	1.73	2.84
1649	1.75	0.09
3853	1.76	0.87
1343	1.76	1.33
1345	1.79	0.48
2232	1.79	0.1
1923	1.79	1.71
1347	1.8	0.07
1288	1.81	4.08
329	1.81	1.96
533	1.81	3.98
179	1.82	4.01
1234	1.82	5.5
1373	1.82	0.51
1182	1.83	0.02
116	1.84	0.36
5727	1.84	2.8
130	1.85	0.03
1270	1.86	0.94
1374	1.86	0.5
5327	1.87	1.42
2966	1.87	3.44
2384	1.87	1.01
1795	1.88	2.56
1307	1.88	1.4
3254	1.88	0.04
148	1.88	0.28
1564	1.89	2.55
2224	1.89	0.68
145	1.89	0.17
1358	1.89	4.35
1371	1.9	2.3
2570	1.91	1.36
189	1.91	4.21
1535	1.91	0.28
340	1.91	4.86
396	1.91	1.61
1842	1.92	1.26
3188	1.92	2.78
3797	1.92	3.66
2203	1.92	2.18
3429	1.92	6.66
1394	1.93	3.78
1311	1.93	1.2
3293	1.93	3.69
2752	1.93	0.93
2204	1.94	3.35
1376	1.94	3.44
3473	1.94	0.07
3918	1.95	1.9
3122	1.95	2.81
1377	1.96	2.23
2293	1.96	0.19
3756	1.96	0.16
3442	1.97	0.09
1101	1.97	1.99
2238	1.98	1.78
3255	1.98	2.61
2312	1.99	1.54
5570	1.99	1.03
2385	1.99	1.55
1112	2	0.28
2209	2	2.37
2906	2	2.79
165	2.01	2.26
2105	2.01	8.34
2848	2.01	1.71
3263	2.01	0.89
1372	2.01	0.45
3709	2.01	0.07
1262	2.02	3.28
2347	2.03	1.82
2992	2.03	4.8
3244	2.04	4
1531	2.05	0.6
3211	2.05	0.01
1177	2.05	4.29
372	2.05	4.17
2339	2.05	1.61
1289	2.05	9.62
1327	2.05	0.34
5211	2.05	2.41
107	2.05	2.02
2727	2.05	3.06
2538	2.06	1.08
3127	2.06	0.95
2453	2.06	1.57
3428	2.06	6.04
2313	2.07	0.7
3159	2.07	4.77
3232	2.07	5.04
2032	2.07	9.51
3208	2.08	0.04
3831	2.08	0.97
1446	2.08	1.41
1238	2.09	4.02
903	2.09	4.72
3422	2.09	5.72
1988	2.09	0.93
3957	2.09	1.27
2294	2.09	0.82
125	2.1	1.04
3206	2.1	6.56
1706	2.1	1.54
389	2.1	6.31
3469	2.1	4.16
182	2.11	0.06
3459	2.11	4.09
3458	2.11	4.79
3106	2.11	7.77
394	2.11	4.73
1360	2.12	2.76
3290	2.12	7.05
3295	2.12	7.05
1864	2.12	0.03
1751	2.12	2.04
330	2.12	1.11
1422	2.12	1.67
3468	2.12	4.92
3771	2.12	4.76
144	2.12	0.24
341	2.13	1.31
2340	2.13	1.53
1487	2.13	2.3
1196	2.13	4.01
1884	2.14	0.07
2612	2.14	1.74
2452	2.14	1.7
2455	2.14	1.59
1255	2.14	0.34
3699	2.14	2.75
149	2.15	0.66
3301	2.15	2.32
2594	2.15	1.04
1938	2.15	1.48
3417	2.15	1.6
2734	2.15	3.19
3302	2.15	4.52
3781	2.15	3.98
1458	2.15	2.48
1648	2.16	0.88
3214	2.16	0.04
131	2.17	0.93
363	2.17	5.15
3432	2.17	5.88
1368	2.18	8.66
3731	2.18	4.67
1620	2.18	0.54
129	2.18	1.66
1929	2.19	1.54
1276	2.19	2.62
3410	2.19	0.81
2381	2.19	0.07
3262	2.19	4.94
3965	2.2	0.41
3672	2.2	0.05
3730	2.21	2.38
2601	2.21	0.34
3216	2.21	0.03
167	2.21	4.88
1779	2.21	0.46
1512	2.22	1.31
3325	2.22	5.29
395	2.22	6.3
5220	2.23	0.99
512	2.23	2.33
3690	2.23	4.43
3502	2.24	0.05
3545	2.24	1.1
1197	2.24	4.65
1188	2.24	8.22
3752	2.24	3.47
3506	2.25	0.01
3927	2.25	1.54
1359	2.25	1.75
3351	2.26	2.05
3858	2.26	2.09
1260	2.26	0.03
5349	2.26	1.08
1209	2.26	5.5
3347	2.27	0.54
2378	2.27	1.33
1504	2.27	1.09
3854	2.27	2.7
3407	2.27	5.44
2184	2.27	1.2
7012	2.28	1.71
1378	2.28	1.14
3441	2.29	6.78
1266	2.29	4.47
1872	2.29	0.68
3605	2.29	5.09
1207	2.29	6.14
3143	2.29	3.62
1283	2.29	8.78
1829	2.29	0.48
1497	2.29	0.96
2819	2.3	0.56
5995	2.3	1.57
3448	2.3	0.11
1865	2.3	0.82
1426	2.31	1.8
3521	2.31	0.62
1811	2.31	1.11
3354	2.31	2.3
1701	2.31	2.05
3472	2.31	7.08
2337	2.31	1.55
2013	2.32	5.74
3794	2.32	1.33
3217	2.32	5.89
2422	2.32	3.24
3673	2.33	1.68
362	2.33	2.93
3215	2.33	7.8
2835	2.33	0.11
1828	2.33	0.37
2189	2.34	1.94
3953	2.34	1.02
2454	2.34	1.83
1523	2.34	1.48
3755	2.34	2.38
3668	2.35	1.55
153	2.35	0.12
3773	2.35	3.79
3997	2.35	1.42
3697	2.35	1.44
3549	2.35	0.16
2364	2.35	2.24
3310	2.35	0.16
1815	2.36	0.65
132	2.36	0.36
3389	2.36	7.07
3942	2.37	0.58
1189	2.37	6.75
3682	2.37	3.16
3482	2.37	0.19
2530	2.37	2.48
1277	2.38	0.97
2228	2.38	2.71
2183	2.38	0.27
3198	2.38	0.03
3413	2.38	5.82
1524	2.38	1.92
3296	2.38	2.79
1224	2.39	3.66
1638	2.39	1.35
133	2.39	0.3
1421	2.39	1.65
2729	2.39	4.12
2288	2.39	0.09
1856	2.39	1.35
3835	2.39	1.72
1232	2.39	6.5
3925	2.4	0.22
1677	2.4	1.35
1906	2.4	1.47
1403	2.41	2.32
2169	2.41	0.01
3930	2.41	0.08
1776	2.41	0.19
3451	2.41	3.69
3535	2.41	0.17
3707	2.41	6.17
2950	2.41	0.96
5113	2.41	0.87
2382	2.42	0.18
359	2.42	4.96
3107	2.42	3.7
3575	2.42	7.86
3855	2.42	1.08
3815	2.42	1.83
180	2.43	0.13
1810	2.43	0.67
5987	2.43	2.97
2168	2.44	1.08
386	2.45	6.59
3358	2.45	6.07
2740	2.45	1.31
2301	2.45	0.06
506	2.46	2.45
1250	2.46	3.38
1639	2.46	1.13
2652	2.46	2.12
3667	2.46	3.7
1557	2.47	1.07
1285	2.47	6.63
3446	2.48	3.87
3553	2.48	7.12
1562	2.48	0.87
1511	2.48	1.88
1911	2.48	0.69
1924	2.48	0.36
2722	2.48	0.11
1777	2.48	0.01
3885	2.48	5.57
1820	2.49	0.89
1628	2.49	1.53
1566	2.49	3.76
3663	2.49	1.4
1907	2.49	0.88
380	2.49	4.69
3816	2.49	0.02
2176	2.5	0.82
2215	2.5	0.25
1184	2.5	2.22
3595	2.5	1.66
3561	2.5	2.39
3768	2.5	2.17
1361	2.5	0.91
3318	2.5	3.06
1837	2.51	0.58
3976	2.51	0.84
2177	2.52	0.36
1821	2.52	1.45
3399	2.52	0.31
2901	2.52	3.79
1428	2.52	0.96
3924	2.52	1.71
3411	2.52	7.13
1513	2.52	1.56
3528	2.53	4.18
2905	2.53	2.56
1871	2.53	1.41
1198	2.53	6.05
1892	2.53	2.32
3353	2.53	0.02
1363	2.54	0.87
2118	2.54	1.49
469	2.54	1.49
3904	2.54	1.14
187	2.54	0.53
1178	2.54	3.32
1839	2.54	1.1
1552	2.54	1.14
1853	2.54	0.9
1824	2.55	0.15
1329	2.56	4.84
1115	2.56	3.94
3260	2.56	1.84
1718	2.56	1.1
3832	2.56	1.72
3603	2.56	1.63
1225	2.56	3.93
2216	2.56	1.5
3474	2.57	3.13
1439	2.57	0.25
2178	2.57	0.97
3922	2.57	0.13
3842	2.57	1.11
3766	2.57	1.92
2241	2.57	1.5
3504	2.57	0.33
1434	2.58	2.35
3943	2.58	3.48
1136	2.58	7.42
1228	2.58	3.1
2415	2.58	2.64
1440	2.58	0.29
1558	2.58	0.73
1529	2.58	0.96
2327	2.58	1.14
1868	2.59	1.38
3916	2.59	0
1448	2.59	0.41
2359	2.59	2.51
3487	2.6	0.24
2544	2.6	2.46
3642	2.6	1.56
1465	2.6	1.84
3633	2.6	1.4
1624	2.6	0.95
1729	2.6	0.25
124	2.61	1.42
3494	2.61	1.63
2400	2.61	1.32
1679	2.61	1.92
3503	2.61	4.07
1118	2.61	2.96
3404	2.61	5.17
3769	2.61	1.34
1356	2.61	0.93
1193	2.61	5.13
1870	2.62	1.28
1435	2.62	0.34
1536	2.62	1.69
1445	2.62	0.33
3463	2.62	2.65
3313	2.62	6.28
3892	2.62	1.83
1239	2.62	0.22
2869	2.63	1.69
166	2.63	0.47
1908	2.63	0.77
1265	2.63	4.25
3564	2.63	2.06
109	2.64	2.27
1888	2.64	1.24
2596	2.64	3.84
3888	2.64	1.4
3964	2.64	1.52
3366	2.65	4.2
3982	2.66	2.25
3848	2.66	0.02
1444	2.66	0.32
5836	2.66	0.05
1195	2.66	7.31
2310	2.66	1.99
3611	2.67	2.2
3631	2.67	2
199	2.67	0.68
1873	2.68	0.47
3488	2.68	2.11
1257	2.68	4.72
3562	2.68	3.21
1186	2.68	4.95
1297	2.68	7.47
3365	2.69	2.84
3223	2.69	4.14
2199	2.69	0.99
2818	2.69	0.78
1734	2.69	0.97
1469	2.69	0.03
1333	2.69	5.39
1819	2.69	1.59
1495	2.69	1.25
1927	2.69	1.47
3101	2.7	6.81
5660	2.7	1.1
3182	2.71	4.33
3594	2.71	3.9
2599	2.71	0.75
379	2.71	6.38
1699	2.71	1.34
2451	2.72	0.44
5116	2.72	1.85
1438	2.72	0.38
1582	2.73	0.71
1317	2.73	2.8
3464	2.73	0.33
160	2.74	0.33
1749	2.74	0.82
2536	2.74	0.04
2735	2.74	0.58
3501	2.74	1.66
2248	2.75	0.95
1530	2.75	1.24
2335	2.75	0.39
3572	2.75	1.84
157	2.76	0.03
1646	2.76	0.56
3507	2.76	2.6
1885	2.76	1.3
3294	2.77	6.33
1483	2.77	1.68
3715	2.77	3.5
1854	2.77	1.04
1886	2.77	1.3
3646	2.77	1.71
117	2.77	0.25
3416	2.78	4.49
3397	2.78	4.5
2955	2.78	1.09
3439	2.78	1.95
3793	2.78	0.11
2807	2.78	2.17
2817	2.78	1.88
1597	2.79	4.44
1450	2.79	1.31
3651	2.79	4.41
1617	2.8	5.08
1443	2.8	0.51
1100	2.8	0.68
2377	2.8	0.93
5712	2.8	0.97
1697	2.8	1.45
1887	2.8	1.13
3760	2.81	5.45
2439	2.81	1
1875	2.81	1.37
127	2.81	1.42
2598	2.81	0.93
2575	2.81	0.11
1905	2.82	1.1
5341	2.83	2.1
3467	2.83	2.46
1315	2.84	3.23
3466	2.84	2.4
2587	2.84	0.37
2147	2.85	4.44
1619	2.85	1.45
3743	2.85	2.06
3402	2.85	2.14
2214	2.86	0.36
3257	2.86	3.01
2334	2.86	0.37
2440	2.86	0.63
1442	2.86	0.86
5104	2.86	0.43
1874	2.87	1.12
3452	2.88	0.01
1312	2.89	1.94
1645	2.89	1.89
3685	2.89	0.11
2249	2.9	0.19
2586	2.9	0.48
2834	2.91	2.12
1287	2.91	1.27
126	2.91	1.07
2326	2.91	1.15
1441	2.92	0.9
1705	2.93	0.84
1261	2.93	8.11
2116	2.93	5.6
467	2.93	5.6
3519	2.93	1.17
1326	2.93	1.17
5185	2.94	0.42
1720	2.94	1.4
3691	2.94	5.9
159	2.94	1.79
3929	2.95	3.56
1137	2.95	1.86
3941	2.96	1.44
3538	2.96	1.83
1402	2.96	2.38
1851	2.96	1.45
1392	2.96	0.94
1838	2.97	1.19
2844	2.97	1.8
327	2.97	1.68
3544	2.98	1.27
3192	2.98	1.57
5968	2.98	1.18
5775	2.99	0.32
1537	2.99	5.85
3729	2.99	4.16
1104	2.99	0.44
3380	3	2.78
1704	3	2.11
		
Max. deviations for best ID is within recommended range. Chosen best chemical ID is suitable for programming the gauge.		
		
		
Selection of best generic ID for ROM based devices like bq274xx		
		
		
Device / Family #1		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
128	bq27421-G1A: 4.2V LiCoO2	1.61
354	bq27411-G1C: 4.35V LiCoO2	2.68
3142	bq27421-G1D: 4.4V LiCoO2	3.95
312	bq27421-G1B: 4.3V LiCoO2	4.09
Best generic ID 128		
Max. deviations for best generic ID is within recommended range. Please chose this ID in your device configuration or device family.		
		
		
Device / Family #2		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
1202	bq27621: (default) 4.2V LiCoO2	2.61
354	bq27621:  (ALT_CHEM2) 4.35V LiCoO2	2.68
1210	bq27621:  (ALT_CHEM1) 4.3V LiCoO2	3.2
Best generic ID 1202		
Max. deviations for best generic ID is within recommended range. Please chose this ID in your device configuration or device family.		
		
		
Device / Family #3		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
1202	bq27426: (ALT_CHEM1) 4.2V LiCoO2	2.61
3230	bq27426: (default) 4.35V LiCoO2	3.28
3142	bq27426: (ALT-CHEM2) 4.4V LiCoO2	3.95
Best generic ID 1202		
Max. deviations for best generic ID is within recommended range. Please chose this ID in your device configuration or device family.		
		
		
3337-1.CSV

How to solve this issue.

Waiting for your reply.

Thanks

Star

  • Hello Star,

    One issue could be that the gauge thinks there's more capacity than there actually is. This could be due to having the CYSNC flag on, RM will jump to FCC at EOC.  

    Battery cells increase their internal resistance over time. The gauge is able to learn the resistance as it discharges, but if the cell is being seated for a long time, then the resistances might have increased and the gauge was not learning. One option is to change the load select to a mode. What is the current mode select?

    Did the customer use the GPCRA0 tool? This tool provides thermal parameters for self heating and helps predict better the load. 

    Make sure the customer has the SMOOTH feature on. Please share the setting file.



    On another thought, looking at the OCV table of the best matched ID (2195), the lowest voltage of that profile is 3V. However, the customer discharged up to 2.6V. Can you explain this? 

    Regards,
    Jose Couso