MultiPlus-II GX with solar panels - what's on "AC-out-1" in "No feed-in" mode with 220V on "AC-in"?

Q&A and troubleshooting
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1

Where will the power come from for the “AC-out-1” output if there’s voltage at the “AC-in” input and there’s excess power from the solar panels (the sun is shining, the battery is charged, and the energy isn’t being fed back to the grid)?

I’ve looked through all the texts in the “Download” section, but I still haven’t been able to find a definitive answer to this question. Each new paragraph contradicts the previous one.

As a result, it’s still unclear where the inverter will get its power in “No feed-in” mode.

2

no feed-in just means no power to the net, but of course he could draw from the net

look at schematc diagram for MP2 with the relais inside

When connected to grid, AC-in, out1 and out2 are linked

3

Thank you. But I haven’t found a schematic diagram yet.
I’d be grateful if you could share it.

4
5

Thanks. My head isn’t quite clearing. The diagram suggests that this is a dumb UPS with additional charging from solar panels. If the battery is charged, then no matter how much sun shines, “AC-out-1” will be connected to “AC-in.” Or am I wrong and there’s some “brain” there after all?

6

This is the block diagram of a MUltiPlus. They dont have any PV input themselves.

In order to add PV you either need to use a DC MPPT, which then charges the battery.
Or you use an AC PV inverter, either on ACin/grid side or ACout side.

ACout is connected to ACin as long as theres mains voltage on ACin. The state of the MPPT, PV inverters or battery has nothing to do with that (by default).

What is your goal, what are you trying to do with your MultiPlus?

7

I want to replicate my homemade hybrid grid-solar power supply circuit.
10 years ago, I designed a simple battery charge controller for a country house. Then, when we got the grid, I added a program to automatically switch between the inverter’s AC output and the AC grid.
Everything worked as expected: as long as the sun was shining and the battery had enough charge, the house received power from the inverter. As soon as the battery’s charge reached critical levels, the output was switched to the grid. Naturally, there was no “return” to the grid.

Now I’ve decided to increase the power and use lithium-ion batteries instead of car batteries.
I was offered a kit with a MultiPlus-II GX hybrid inverter and a 250/70 MPPT controller for battery charge monitoring.
I’m ready to buy it. But I can’t figure out if this rather expensive device has an automatic control system with a similar algorithm. Or will I have to re-solder this switch. And also somehow receive information from the inverter that the battery charge has dropped below a specified level.

8

AC-out doesnt make much sense in a house ESS installation

Imagine a boat, camper,…

critical loads like the fridge, lights are on AC-out 2

luxury things like a dishwasher are on AC-out 1

If you have power failure, battery only supports the critical loads, luxury loads are switched of

But some people - the ones that have fear of power failure - also use it in houses, especially in 3-phase systems with 3 MP2

9

The problem is that the refrigerator also runs at night. And sometimes there are clouds in the sky :slight_smile: Batteries are quite expensive. And the roof of my house is a little smaller than a football field. I can’t get by without power from the grid. There is one, but it’s intermittent :frowning:
So I’m looking for a “hybrid” system to get a stable power source without spending too much money.
And I haven’t yet determined whether the equipment I’m being offered allows for this or not.

10

why it shouldn´t?

Compare it to water: you could store some rain water - as long as you have some you could use to water the garden

If its empty you have to zse water from the supplier

Victron does all that automatically - with electricity

11

What a wonderful metaphor :)))
I’m all for it!
But I don’t know if “Victron” will add water as the barrel empties, or if it will pour it out regardless of how full it is :wink:

Please forgive my poor English, all complaints go to Google Translate :slight_smile:

12

victron will first take the water of the tank - here battery

if the line to the tank is to weak, it will take additional water / electricity from the net

if the tank is empty, it will take all water / power from the net

next morning, sun is shining- battery will be reloaded, but only whit what is leftover from your house consumers

13

The difference here is whether you use the ESS functionality or not.

Without it, then it will behave like a UPS, once grid is avialable, the batteries get charged from the grid, and kept full all the time. Thats also the standard behaviour for mobile use.

With ESS your system works as you want it. It will use power from the batteries when available, let the PV recharge them, and only if the batteries are empty it will take power from the grid, but also only to run whatever load is connected.

Theres more options for both of those basic functionalities, bot those are the very basics.

14

Here’s the answer I got. It’s a little different from the plumbing analogy :slight_smile:

"…the solar panels would charge the battery/DC side through the MPPT controller, and the MultiPlus-II would supply the selected loads on AC-out-1…

…in “No feed-in” mode, AC-out-1 gets power first from the available solar energy through the MPPT/DC side, then from the battery if allowed by the settings, and if that is not enough, the remaining power comes from the grid through AC-in.

When the grid is available, AC-out-1 remains synchronized with the grid. If the battery is full and there is more solar production than needed, while feed-in is disabled, the system limits PV production instead of exporting excess energy to the grid."

15

Thats correct for ESS with DC feed-in disabled

16

yes, plumbing is little different

They system also has limits

if your MP2 coild only provide 3000W , you need 4000W - 1000W will come from the net

I´d rethink using MPPTS - did you think about Micro-Inverters like Hoymiles that produce directly AC 230V AC

Most of the time your PV production will be directly used by the House