question

nuxland avatar image
nuxland asked

3 phase Multiplus to limit Current per Grid phase

gridlimit.pngThere seems no where to configure my Grid main braker amperage limit.

I have grid parallel connected system and grid main braker 3x20A. Also having separate grid meter set up in victron system so Victron knows what is drawn from grid.

If I put my batteryies to charge from grid with GridSetPoint 9000W and then use in my house like 3kw from L3 phase then input from GRID will be to much on L3 phase.

If I could set somewhere limit like 18A per phase in Grid meter then if I load my L3 with 3kw then batteryies are charged from other two L1 and L3 phases from more current and from L3 current would be lowered to 18A.

Attached is image how it is when there is load on L3 and therefore L3 grid is more than i would like it to be.

ESS
gridlimit.png (48.5 KiB)
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2 Answers
nuxland avatar image
nuxland answered ·

Did a little more investigation and seems that ESS tries to follow mi grid setpoint but is utilizing multis with same power. I have 3 phase system with 3pcs of 5000kv 48V multiplus II.

So lets say 8000W Grid Setpoint and load is around 300W per phase, then each multi will charge with 8000W - 3x300W=7100W / 3 = 2366W and around 2666W from grid in each phase.

No my dishwasher will start heating water and L3 load will increase from 300W to 2600W. ESS will lower each multis to 8000W - (2600W + 300W + 300W) = 4800W / 3 = 1600W. But power drawn from the grid will be L1 = 1900W, L2 = 1900W and L3 = 4200W. And that L3 will be around 17,5A.

Overall that is not wrong because if all multis are loaded equally they will last longer.

But if I would like to set my Grid Setpoint to 12kw instead (that should be 2kw lower than maximum that I can afford with my 3x20A main breaker and maximum that multis could charge if there is no house load) . Each multis would then charge with 2933W of power and then L3 input from the grid would be L3 = 5533W and that is over 23A.

So I think there should be a new feature to set max Grid amperage per phase. And if I could set it 19A in that 12kw example then ESS should lower L3 charging power to 1960W and increase L1 and L2 charging power to 3420W. I would then still draw 12kw power from the grid but all L1, L2, L3 phase's load is under 19A.

And this is the reason I can not charge my battery with 12kw from the grid because I could potentially overload my braker if there is a big non-symmetrical load in one of the phases in my house at the same time.


PS! I think when you use OUT 1 from multis to power your house then multi would use "Input Current Limit" option because house load would go through multi then. But I have grid parallel system instead and multi input is not seeing house load.

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jan-muller avatar image
jan-muller answered ·

Did you find out? I have exactly the same problem with charging my car (that only uses 1 phase)

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