question

Herve RV Nizard avatar image
Herve RV Nizard asked

Multiplus II AC OUT 2 only when grid is connected? Or just available.

Good day. I read a lot of Q&A on the subject, but still have 1 question:

I understand AC OUT 2 works if grid is available .

But does this mean that it only works if AC OUT 2 "feels" grid is available (whether using grid or not), , or does it mean that AC OUT 2 loads must be powered by the grid ?

Thanks.

Details are as follows:

system Is 3x Multi II 48/5000 in parrallel , with ESS

2 SMA PV inv SB 5000 on AC OUT side

1x SMA PV inv SB5000 on AC IN side

For a specific system, i would need to use AC OUT 2 for large loads when there is enough sun or when grid is available (even if not used) , but would NOT want these to be powered when grid is not available .

AC Out 1 would have essential loads connected , and should be the only one operating if from batteries. (Simply because the battery bank cannot handle such large loads as those on AC OUT 2).

SO : 1- in normal times, with grid available, :

- during daytime , loads connected to both AC 1 and 2 are powered from the PV inverters when there is sun ,

If not enough sun, AC OUT 1 is taking from batteries, and AC OUT 2 is taking from the grid ,

- at night, AC Out 1 is taking from the batteries , but AC Out 2 is taking from the grid

2 - If the grid fails , all AC OUT 1 loads are powered from the batteries, and all AC OUT 2 loads are off .

Thanks .

Multiplus-IIESSac out 2
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

4 Answers
waninae39 avatar image
waninae39 answered ·

ac2 only works only with the grid on

it does not use the convert/invert path like ac1

ac1 is for loads that must stay

ac2 is for loads like an air conditioner etc

3 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

lifeingalicia avatar image
lifeingalicia answered ·

Think about it as AC1 AC2 is one line just split from grid AC Both are controlled by the Multi.

When grid fails grid is isolated upstream (grid) to safeguard any linesmen. AC2 is shed. AC1 is powered by the inverter / battery.

Normal operations AC1 AC2 are powered by the Multi. Grid setpoint - SoC - max discharge of inverter - controls AC and grid demand.

If required power is drawn from batteries to top up PV up to max inverter setting rest from grid.

https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

Also note: If you use external meters grid is used first then balanced to grid setpoint (if possible) using bat.

If you use the internal ones, its the other way round first bat then balanced out by grid.



2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

nickdb avatar image
nickdb answered ·

AC2 behaviour can be overidden with an assistant.

It is a regularly discussed topic. Look for iirc general relay assistant.

4 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Kevin Windrem avatar image
Kevin Windrem answered ·

The measurement of output power is made before AC 1 and AC 2 outputs are split. So there is no way for the Multi to know what AC consumption is from the AC 1 output and which is from the AC 2 output, and no way to specify that AC 1 power comes from the battery and AC 2 comes from the grid.

Grid power when available will be used over battery power unless you have an ESS system configured. Then the logic shifts to prioritizing consumption from battery over grid but a low state of charge will trigger grid power usage.

If you want to insure that some loads only draw power from the grid, then you need to place them on the input side of the Multi/Quattro.

2 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.