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toeks avatar image
toeks asked

Erratic charging from Multiplus-ii

Hi there.

I have the following system at home wich is grid tied:

Multiplus-II 5000 with MPPT 250/100 charger, 2400w of 400W Jinko Panels, 1 x Pylontech US3000c 3.5kw battery.

If I know beforehand that we will have a power outage or loadshedding I set the SOC to 100% in ESS. But when the grid comes back on and the batteries get charged during the day with PV energie, the charging is very erratic. If I change the SOC to anything else (i.e. 95%) then it charges normally according to outside conditions and the charge doesn't fluctuate. What could be happening?

Regards,

Multiplus-IIbattery charging
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Alexandra answered ·

@Toeks

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom#minimum_battery_sizing_recommendations

Your battery bank is undersized and being punished by the system. 37A max charging on one module. 2400W is 50A potential at 48V.

Is it connected to the GX and are you running DVCC? SVS and STS?

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toeks avatar image
toeks answered ·

Thanks for the reply Alexandra.

My setup is connected to the GX and DVCC is enabled. SVS and STS isnt enabled at the moment though. I think the Pylontech is handeling the battery management at the moment.

I will definately be adding more batteries to the system as soon as the finances allow it, but for the meantime the one 3.5kw Pylontech will have to do.

I'm new to solar, so any information is highly appreciated. Please let me know what you think and if I need to change something on my setup or add any additional hardware (other than another battery, which is in the pipeline).

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Alexandra avatar image Alexandra ♦ commented ·
@Toeks

The solar will only produce what it is told to do in an ess system. If it is up and down and the battery is charge then the fluctuations may be load based.

With the Pylontec just keep to the charge and discharge currents. So I think your model is 37A discharge.

37x voltage is the max draw from the bank. So you wont be able to run at the full capacity of the inverter right now without potentially damaging the battery

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toeks avatar image toeks Alexandra ♦ commented ·
Thanks again for the input. As long as everything is fine and I'm not damaging anything, I can live with keeping it at 95% charged until I get another battery.

Out of curiousity why did you ask about SVS and STS?

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