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blufly asked

SOC 100% but only 12.1v

Hi Guys - I have 4 120ah sphere lithiums charging off 8 x 180w solar panel on my basestation - solar charger is a victron smart solar 150/100 and i also have a Smart BMV 712 - I had to put the van in my shed to do some maintenance so it wasn't in the sun - normally the system is continuously charged so never had a problem before and had it made to be able to survive in storage mode for at least a week - after 2 days the my ph lost Bluetooth connection but then it came back on again and was on 78% so didn't worry the next day all the power had shut off and nothing worked so i went to get a 3pin plug to hook up the caravan lead to the house and when i came back it was back on again and now says 100% SOC but only at 12.09 volts . I havnt plugged it into the mains yet and want some advise what to do as I havnt seen this before and usually sits between 13.2-14.2V and it defiantly isn't 100%SOC as hasn't had a power source or sun for 4 days now

BMV Battery Monitor
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Uwe Kilon avatar image Uwe Kilon commented ·

Hallo, was ist denn ein gutes Mass für den Ladezustand, wenn nicht die Spannung?

vg Uwe


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kevgermany avatar image kevgermany ♦♦ Uwe Kilon commented ·
Normaleweise BMV series. Zb. BMV712
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nickdb answered ·

If power was completely lost, the BMV may automatically start at 100% when it is turned on. There is a setting for this in the menu - Battery starts synchronized.

It would then need a proper charge cycle to sort itself out.

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blufly avatar image blufly commented ·
hi nick - yeah it went completely dead -but shouldn't have in such a short time - Should i plug it into 240v and just let it charge up? and it will then reset after its fully charged or do i need to then re balance or do anything to the bank?
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nickdb avatar image nickdb ♦♦ blufly commented ·
Just let it fully charge itself, then do a normal discharge/charge cycle.

Perhaps post your shunt settings here and the battery specs. Does the pack have a bms you can connect to?

It sounds like either the soc isn’t tracking right (settings) or the battery bms isn’t happy.

Voltage isn’t a good measure of soc for lithium batteries.

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