question

johnhb avatar image

Grid parallel load vs. AC out 2

Good-day. I am trying to understand the difference between a "grid parallel load" and a load on "AC out 2" when using a Quattro or a Multiplus in ESS mode. Clearly, the inverter does not even know there is a grid parallel load unless it is configured to do so and there is an energy meter attached to measure the power flow at the grid input. (Any guidance on how to configure these aspects would be welcome). I have attempted to list the characteristics below - feel free to correct me :-


Load on AC out 2.

Powered firstly by the inverter (until the combined "AC out 1" + "AC out 2" exceeds the inverter capacity) and then by AC mains as well. The combined load must not exceed the rating of the transfer switch.

If the AC mains falls away, the AC out 2 is cut off.

Provides a way to make use of excess Solar PV yield on non-critical loads.


Grid Parallel Load

Powered firstly by the grid (under normal curcumstances does not require any additional capacity from the inverter).

Normally, the inverter drives the loads on AC out 1 (and AC out 2) as required. Under some configured conditions (not eactly clear how), the inverter starts to "push" power out of "AC in" and thus contribute to this grid parallel load. It can supply this load completely such that no power is drawn from the mains supply. The energy meter can be used to regulate the amount of power supplied via "AC in" so that it is equal to, but does not exceed, the grid parallel load.


Is there any guidance as to which approach can or should be used under which conditions.

Thanks,

John Hope-Bailie

parallelac out 2
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1 Answer
ejrossouw avatar image
ejrossouw answered ·

Hello @johnhb

The Multiplus is a bi-directional inverter and it depends on whether you require backup power in the event of a mains failure or not, have access to solar etc. how you set it up. Is this in a house, boat or RV?

I have a pure self consumption ESS and no solar configured only connecting the ACIN to my consumer board. No ACOUT at all. In conjunction with the ET112, the multiplus will run up to it's max and then simply top up with grid (below red at 18:00) as required. This offers no backup power if the grid fails I however use it to buy energy cheaply in the early morning hours (red) and then consume it during the day. As you can see below, blue is battery with only occasional red grid when the electric oven runs and the inverter reaches max capacity. I very much halved the cost of my electricity bill

For the the second option, the best way I can explain my understanding of it is, if you want to configure AC1OUT loads in off grid mode or UPS mode, it should not exceed the 13A output capacity of the inverter for when the grid falls away. Typically used for lights and some sockets depending on the size of inverter and battery capacity. When however connected with shore or mains passthru, you have an additional 32A across AC1 & AC2 OUT and you choose how to set it in line with your requirements. AC2OUT will best be used for e.g. electric oven, water heater etc, when there is shore/mains but a proper design warrants a comprehensive understanding of what you want to achieve etc., batteries, etc. How long is a piece of string? Hope this helps.



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Many thanks - very interesting. I assume that you have configured the inverter and CCGX to discharge between certain times, and to charge between others. Please point me to where I can read up about this time-based behaviour.

It is all part of ESS. Charging can be configured on a schedule and also SOC percentage. Happy reading.

https://www.victronenergy.com/live/ess:design-installation-manual

Спасибо за информацию! А если по этой схеме разряжать аккумулятор только с помощью функции Power Assist? Мне нужно только разрядить батарею на утренние и вечерние пики. Чтобы не выбить входной переключатель в плате