How to reduce charging power from grid with ESS installed?

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lucode asked Dec 16, '21

How to reduce charging power from grid with ESS installed?

I have a somewhat limited feed in from the grid and want to charge my battery at night at the cheaper tariff. But at the same time I want to charge my EV (car) too. Because the reduced electricity price is only for 6 hrs I would like to charge both batteries at the same time, but without risking to suck to much from the grid.

I know there is a parameter in the VE connect settings that allows to limit the AC input current. This is set to 30A in my case. But this param limits all the current from the grid independent from the use (inverter or charger).
If I would like only to charge the battery with 2kW it would need a setpoint of about 9 A and not 30 A. Together with my car charger - that consumes 3.5 kW - I get a total of 5.5 kW, which gives me a nice reserve for other consumers as the heat pump and the water pump. Which of course are periodically turned on.

I think this a feature of which many other could profit to.

ESS

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Answer 1 · 2021-12-16T14:50:29Z

tnt369 answered · Dec 16, 2021 at 02:50 PM

Under "Charger" you can enter the max. charging current (DC).

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lucode commented · Dec 21, 2021 at 02:35 PM

Yep I know but this reduces the charging power from the panels too. That's not the desired behavior, because I need all the surplus power going to the battery.

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Answer 2 · 2021-12-16T16:32:47Z

Matthias Lange - DE answered · Dec 16, 2021 at 04:32 PM

The PowerControl feature will automatically reduce the charge current if you need more power on the output.

e.g. you set the input current limit to 30A and you have 20A of loads running then the Multi can only use the other 10A to charge the batteries. If you switch off some loads, the Multi will increase the charging current.

But if you want to reduce the charging current permanently you can set that on the charger tab in VE.config.

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lucode commented · Dec 21, 2021 at 02:39 PM

I assume your refer with PowerControl to the Shore Limit (AC input current) parameter? I think I will need to stick with this and find a value which is a good compromise between enough power to feed the critical loads and not to suck to much power from the grid during night charge.

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Answer 3 · 2022-01-02T14:31:29Z

alan-falck answered · Jan 02, 2022 at 02:31 PM

Hi (newbie here) my issue (similar thread) is some days ESS works perfectly using battery overnight (Self Consumption) other nights is goes into sustain mode at 60 or 80% SOC My cut off is 20% return to the grid. I can't find any way to change this setting?

Alan

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nickdb ♦♦ commented · Jan 02, 2022 at 03:16 PM

Some searching on this forum should show a few threads on this topic.

Your SOC may be incorrect - it is an estimated value, which with an iffy bms or shunt setup could be plain wrong at times. Your system may well be hitting voltage thresholds.

There is way too little detail here to do anything other than guess.

Would suggest you look at the battery voltages at the times this happens and compare it to your assistant and charger settings.

Knowing proper detail about what you have and how it is set up will be needed, probably best in a new thread, should the existing ones not help.

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Answer 4 · 2022-01-08T14:06:41Z

alan-falck answered · Jan 08, 2022 at 02:06 PM

Thanks for the guidance, I'll start a new post with all the detail.

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