Based on the recommendation and reviews, I bought my first pack of batteries from BLS battery store. I top balanced, capacity tested, and charged and believe that I have one cell (maybe two) that is not allowing the pack to meet its capacity. Ive been in contact with BLS who is blaming the xiaoxiang bms. They are stating that I have to capacity test the individual cells for me to replace any, but how do I capacity test a 3.2V battery when my only load is a 24V inverter? Any other suggestions on getting this resolved?
Long thread of text, but support conversation below:
Long thread of text, but support conversation below:
Yesterday 15:38
Thank you for extending purchase protection window. I have charged, top balanced, and capacity tested the cells and believe that I have a single low-performing cell. My capacity test totaled 163Ah and when the single cell hit 2.5V, other cells were still at 2.83V or higher. Below are images showing the cells top balanced at 3.512V before the capacity test, the cell voltages just before BMS low voltage cut-off at 2.5V, and the capacity on my shunt meter showing 163Ah when restarted after low voltage cut-off. I am using an overkill 24V 100A BMS, Longwei 30V 10A Variable voltage DC power supply to charge, 300A shunt battery monitor and meter, and a Meterk MK06 multimeter to verify the BMS voltages readings and the shunt meter current readings.
Yesterday 18:48
你好,我看到您的测试有一个电池容量不好,这个情况我建议您先对电池组充电,然后对这个低电压的电池再单独充电,然后放电测试,谢谢您,圣诞快乐!
Hello, I see that your test has a bad battery capacity. In this case, I suggest you charge the battery pack first, then charge the low voltage battery separately, and then discharge the test. Thank you, merry Christmas!
Alibaba Translation
17:11
Thank you for the response. I recharged the battery pack and there is no need to charge the low voltage battery separately. The low voltage cell, cell 5, limited the charging, hitting 3.6V while the remaining cells in the pack were ~3.4V. See image below.
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19:48
不瞒你说,XIAOXIANG BMS总是这样的情况,我们其它使用别的BMS的客户没有这样的反馈,所以我们还是建议您单独测试细胞,我们很多客户更换了BMS后就没有任何问题,有时候不是电池的问题,是BMS不可靠,不准确,谢谢您
To tell you the truth, this is always the case XIAOXIANG BMS. Other customers who use other BMS do not have such feedback, so we recommend that you test the cells separately, many of our customers do not have any problems after replacing BMS. Sometimes it is not the battery problem, but BMS is unreliable and inaccurate. Thank you
Alibaba Translation
23:00
Thank you for the response. I have verified the voltage and current data with a Meterk MK06 multimeter
Read
I can assure you I have accurate capacity and voltage measurements
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23:06
明白,您单独测试一下怀疑有问题的细胞,根据我们客户的反馈,xiaoxiang bms的确不太可靠,
I understand. You can test the cells suspected to have problems separately. According to the feedback from our customers, xiaoxiang bms is really not reliable,
Alibaba Translation
23:14
如果您测试了某个细胞容量不足,或者有缺陷,我们会免费给你更换
If you have tested a cell with insufficient capacity or defects, we will replace it for free.
Alibaba Translation