Hello

I have a 48V boat system with a Lynx BMS, six Smart Lithium batteries (3 parallel banks with 2 batteries in series) and a Multi Solar RS. The bank has been properly balanced before.

Now, after 5 weeks I came back to my boat and charged the batteries from around 60% to 100%.

A few things that I don't understand.

1. The state of charge was way off. The RS stopped charging at around 53.91V because SoC supposedly was 100%. Why does this happen?

2. Then I manually set SoC lower and manually checked battery voltages. When batteries hit 27.6V they started balancing. All good.

3. Finally at 56.8V (absorption voltage) the charger stopped and voltages immediately started dropping. 5 out of 6 batteries managed to balance but the 6th battery did not because voltage dropped too quickly. It now says "imbalanced". Absorption time is set to 2h. I thought that I should stay at 56.8V for 2 hours in order to give enough time for all batteries to balance. What went wrong?

4. Before charging the battery cell difference were very small, never more than 0.01V. The batteries only ever started to be imbalanced at the end of the charging sessions. Why charging full and balancing the batteries at all as long as I can manually check cell voltages?

5. My multimeter constantly tells me that battery voltage is 0.2V higher than indicated by the BMS. This seems a rather big difference. Whom to trust?

I am no professional but eager to learn. Thank you for sharing your knowledge.

Aurel