question

Noel Rath avatar image
Noel Rath asked

Batteries fully charged, SOC sets to 100%, voltage slowly drops

I have two 200Ah batteries in parallel, Smart Shunt connected correctly, BlueSmart charger and alternator charger and MPPT solar charger. I'm in the process of replacing the old solar controller with a Victron and adding the temperature sensor to the Shunt.

Once charged the voltage indication slowly drops to around 13.5 volts. When e.g. I start charging from the alternator, it charges quickly until 14.2 volts and then stops and voltage drops. The SOC remains at 100%. These are my settings with no loads at all.

Is everything setup correctly?

shunt-settings.pngshunt-monitor.png


SmartShuntSOC
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shunt-settings.png (133.7 KiB)
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1 Answer
kevgermany avatar image
kevgermany answered ·

Sounds normal. Batteries usually charge at a higher voltage, then when full switch to float and the voltage drops.

But. The settings in the controller don't look right. This will lead to the controller switching to float too early before full charge reached.

What batteries are they (chemistry/type as well as brand) and what are the makers recommended charge settings?


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Noel Rath avatar image Noel Rath commented ·
They are Lithium batteries, VoltX brand. The user manual states that for optimum, you must charge at 14.6 volts. In the parameter section it states that the charging voltage is 13.8~13.8V.

I'm somewhat confused by all this. What should the setting be then?

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