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theshenks avatar image

Priority solar in ess connected to ac, ac2 question

Priority solar in ess but connected to ac what happens to ac2? does it still feed from the grid

ESS
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kalito avatar image
kalito answered ·

Interesting and surprised this has not been answered yet. @Theshenks and @Daniël Boekel (Victron Energy Staff) my experience on AC2 out on Multi with ESS shows that in the presence of grid with self consumption setting with battery life AC2 behaves just like AC1. A disappointing discovery as the whole point of AC2 is loads you really dont want on backup/solar unless under special conditions (such as battery full amd PV to power these etc. )

You put your hot water heater on AC2 it works in bypass when system is backup. But alas implement ESS and your hot water heater runs on batteries at night if switched on unless you limit inverter output so that when you switch AC2 load excess above limit comes from grid.

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Hi @Kalito

It wasn't answered because the question wasn't clear...

But as you describe it: yes AC2 out is the same output as AC1 but switched with a relay.

The history for this function is off-grid systems (boats, RV's, house without grid, etc). where some loads should only be powered if shorepower / generator input is available.

With the use of assistants, a lot of flexibility is possible for when AC2 is switched on/off, but technically it's the same output as AC1 and the system cannot measure what output is drawing what current.

The solution for you is to run the water heater in front of the inverter, not on the output.

kalito avatar image kalito Daniël Boekel (Victron Energy Staff) ♦♦ ·

Very good clarity there thanks so much for unravelling this. The historical bit makes lots of sense. You have answered what I had asked in another post. I will tag you there.

What do you mean by infront of the inverter? I use the inverter as the energy meter.

Lyndsay Cotton avatar image Lyndsay Cotton Daniël Boekel (Victron Energy Staff) ♦♦ ·

I am not sure of the accuracy of or my understanding of your last sentence.

I have loads; eg: such as the geyser "in front" of the inverter and still drawing from the PV.

Its almost as if the PV just feeds everything unless there is a grid failure, then just AC 2 is active


Hi @Lyndsay Cotton

In an ESS system, if you select (ESS menu) 'grid metering' 'internal' instead of external, the system will not power loads in front of the inverter.

Lyndsay Cotton avatar image Lyndsay Cotton Daniël Boekel (Victron Energy Staff) ♦♦ ·

@Daniël Boekel (Victron Energy Staff) Thankyou for your response.

Would I still be able to meter what is being drawn from the grid. All my installations use the Carlo ET112 meters (after main switch - before any DB loads - be they before inverter or AC1 & AC2

Notwithstanding your answer, what is the difference between internal and external metering on ESS.

Hello indeed I think your explanation seems quite correct. We have ESS installed and we have separated AC2 loads as the loads which should only work when mains is available. However in ESS, when the system is for example using mains and also the battery it seems to supply both AC1 and AC2. Then quite frequently the system disconnects AC2, although mains is still available... Is this a bug of ESS ?


I have the feeling under ESS batterylife, the system disconnects the AC2 whenever an overload situation happens, however this is not what I understood from AC2.


What is the solution to this problem ?

kalito avatar image kalito bulraydin ·

I have observed AC1 drops on some days and I have seen the overload led even when load was actually 500W. I read somewhere that this has to do with the quality of the utility power coming in and associated frequency issues. ESS is a Victron fix at making its components work like a those in a hybrid system. The robustness of the mix unfortunately seems to give away something.

I have nothing on AC2 and if I do it will be what I would put on AC1 and just use it as an extra port and programme it to always be on

Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Theshenks

Could you explain what your question is?
Also describe your system to get better answers.

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