Ignore AC Input

DIY
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1

A few days ago I asked help in a topic, but nobody came to rescue.
In the meanwhile, some dozens of YouTube videos later and a few days to think, I came to the conclusion that much probably I’ll need the ignore AC function.

In resume::
I have 3 multis 5000/48 in 3 phase, that when I start them up, although they have a full battery, they will start passing the grid to the output.

What I want is give priority to the battery and MPPT and only if the SOC gets low, them let the grid come in.

So apparently, there are 2 or 3 ways to accomplish this.
I will much probably use the Cerbo GX relay to control the input relay of the multis as if a generator was. This way if there are adjustments to be made on the SOC level, I can do it from the VRM, no need to connect the MK3.
So, in case of low SOC this is covered. What about in peak shaving?

Imagine that I have the car charging at 3500W and the oven kicks in at 2000W. This would be, 5500W, more than the inverter can handle.
My grid is also limited at 4600W, so it can’t handle all the load by itself.
What will it happen here? Does the grid kicks in also? Will the Multi help here? How much?

Thank you in advance

2

Have you not looked at ESS?

You can’t peak shave unless grid is connected, if a big load turns on the grid - first the system has to be synchronised to, then accept and relays connect before assist from grid can happen. So will be too slow unless it is a sustained load (the load connect can also be done with the generator start stop as well)

Your input current limit will be obeyed at all times. So if your load is too high for the incoming grid limit, the system uses battery/solar to power assist if they are sufficient. So i hope you have sized your battery bank accordingly.

3

Actually, I took a quick look at ESS, but I read that ESS is not suitable for an off-grid installation.
I’m indeed not off grid, but I have faith in my math and according to it, I’ll not need much grid.

At the moment, I can’t inject anything in the grid, and because I have a smart meter, they will see it! If I do it, I can have problems because I’m finishing my overall electric installation at home, and I’m not yet in conditions to ask the inspection, Only after inspection, I can inject. Also, here in Belgium, you almost pay to inject energy, it’s not interesting.

As I said before, my grid is limited to 20A (4600W) per phase.
I have almost 16kWp, and I’m already prepared to almost 20kWp.
I have 4x Lithium NG batteries for a total of 20 kWh in 2s2p for 48V.
3 Multis in 3 phase configuration.
1 EV charger; the car uses a bit over 5kWh/day during the week. It doesn’t ride in the weekend.
I’m still changing things here and there with my consumer unit to see what loads must go in each phase and to balance the loads the best I can.

Because of my usage profile, and the possibilities the Victron EVCharger gives, I have it set to auto mode, so my wife arrives home around 16:00, connects the cable, and the car starts to charge between 6 and 15A if there is sun available. Probably, next week after the winter time arrive, this will change a lot.
Why 15A? To use the maximum sun available directly from the MPPT instead from the battery, before its night. The downside of 15A is, it that this situation severely limits my usage of one of the phases during the busiest time of the day at home. So, I would like to bring the grid to cut those peaks above the 5kVA capacity of the inverter, but i’m lost in how to do it.

I wished that existed one charger connected to the DC busbar and that it could directly put dc in the car; or take it from the car :slight_smile: Hint Hint @Lpopescu :slight_smile:

As a solution, I could:

  1. Buy one other inverter to put standalone, only to charge the car directly from DC. This would free the multis power to feed the house. Much probably, I wouldn’t have power problems anymore.
  2. Keep the car charger in auto mode, but for that I need the grid to come in and complete the peaks; But I’m absolutely lost on how to do it.
  3. Moving the car load to an off-peak time; ex: always charge the car after midnight @6A This would fix the power peak problem in the same way.
    It would however bring the problem that I would never use the direct solar from the MPPT and would always use the batteries. Around 25% of my home batteries would go to the car, every day. This is unnecessary cycling, and limiting my available capacity for the house.

If only I could schedule also modes and not only the time and charging current. ex: auto mode during the day, scheduled mode @6A during the night. Please @Lpopescu add this feature. :pray:

Any ideas of the best way to achieve this?

With my best regards