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alieren avatar image
alieren asked

How to make Multiplus II work with PV panel in ESS?

We have a multiplus II 48/5000 and a mppt 250/100. When the grid interrupt, we want to, if the system have solar energy (PV connection), loads are fed by PV. But we tested this situation, loads are fed by PV and Battery even if PV is connected. We do not want this, if PV is connected, preferably loads are fed by PV. After PV power finish, system use battery to feed loads. We installed the ESS assistant and configured it from there. But when pv power is less than load, it uses battery or grid. In this case, solar energy cannot be used. If the PV is connected, we always want to use PV to feed load firstly. How we can configure on ESS assistant?

Multiplus-II
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Alexandra avatar image Alexandra ♦ commented ·

Hi @alieren what you are describing it exactly how ESS works. PV will feed the loads first if it is sufficient.

If the sun is not great the PV will not keep up with the loads so the power has to be drawn from somewhere. It will use either your batteries or your grid (if available) depending on SOC set and grid point set.

If it draws the power from the batteries then the PV will charge the batteries back up when the sun is bright enough. ESS will prioritize the battery charge up over loads if you have set it to keep them charged in the ESS menu and it will use the grid to power your loads until it has reached the charge you have set it to maintain.

So really if you are trying not to use Grid power then you have to allow the system to use more battery. For example keep SOC at 95% (in case of grid failure) so it uses more PV for loads. Since anything powered from your battery is PV powered as it is charged from PV, you are technically using PV for loads that way.

And if you are aiming to not use battery then your loads will draw more from the grid.

How do you want your system to behave?

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Alexandra avatar image Alexandra ♦ commented ·

@alieren

The other way to make sure your batteries do not drain and you do not use grid when PV is not enough it to reduce your loads, in other words switch off appliances/things that are using the power.

Or you could add a PV generator to your system with more solar panels, something like a Fronius PV inverter for example.

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