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markbng avatar image
markbng asked

3 phase battery system. What do I need?

Hi,

Currently I have a 10m long wire 5*10mm2 wire to my storage room. In the storage room is a 18kW inverter from growatt. I will use this wire to also connect the 380VAC (3 phase, 16A each phase) battery charger/battery power inverter to the grid. So this connection will also be connected for a rechargeable battery. My RCD is now 30mA, but when it's grey weather outside this RCD activates. What is a good value for this RCD here in the Netherlands? 300mA? What characteristic? So the Battery will also be connected to this connection.

I want to use 2 * 16 kWh batteries ( DIY-koffer voor 48V 300ah Actieve balans-accu+behuizingsaccessoires › Basengreen Energie ) for my system. This 16S/314Ah/48V battery needs a device that can charge the battery, but also can provide power back to the grid. It would be nice if this system can charge a certain amount of power and in the evening can discharge a certain amount of power. The charging and discharging will be handled by home assitant. Home assistant will read the smart meter via the P1 connection and the discharging will also be handled by home assitant with EPEX prices. It's important that I can tell....Please charge a x amount of watt (prefer to control each amount per phase). But more important is the releasing the power to the grid again. If I use for instance L1 250w, L2 400w, L3 1200w, then I want to be able to compensate that with power released by the battery inverter. What devices of Victron can I use? I am a hardware design engineer, so I can make the system by myself. But where to start with Victron? What devices?

Also an option would be removing the growatt inverter and replace it with a direct charging circuit for this system (PV and AC powered). This way you don't have to make AC of the solar power and from AC convert to battery power again. I don't want to spend so much, but have a good over all system. What is good for my situation? Growatt solar power is 18kW and has 17,6kW max at the moment.

1 last thing. I also want to be able to set the maximum voltage of the solar/battery inverter when I choose the last option. I want to be able to set the max AC voltage to 257VAC for instance. Our power network provider switches of solar inverters by increasing the AC voltage level. If the battery is full, I want to be able to deliver the excess power to the grid (at a higher voltage).

Thanks for your help

Best regards,

Mark

battery chargingLithium Battery3 phase
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1 Answer
Duivert NL avatar image
Duivert NL answered ·

Hi you could use 3 multiplus 2 inverters, an cerbo and mppts, i do just the same in the netherlands

You should take a look a the ESS manual, see link

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/index-nl.html

Increasing voltage to 257V is not possible, you cant increase voltage from grid, grid also should not be higher then 253V, then inverters will shut off, multiplus will disconnect grid (dutch gridcode)


For PV if you would like to change from AC pv to DC use mppts, effieciency is higher, but however a mix of ac and dc pv is best of both worlds


For system design contact your local dealer and/or follow the free victron professional training courses

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