ESS drawing too much grid power, should be battery

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mfred68 asked Jun 20, '24

ESS drawing too much grid power, should be battery

After a first day of using ESS I managed to charge my 42kw battery to 33%, but this evening I was using over 4000w during cooking and noticed it was drawing over 500w from the grid, surely this shouldn't happen. My multiplus ii is 10kva and I did not apply an inverter limit during ess setup, But im wondering if it has anything to do with me setting my ac coupled pv to 4000w? In ve config?

Is there anything I can do to stop such high grid draws?

Does peak shaving have anything to do with it as its set to above maximum soc only, and this is an area I don't understand, can anyone explain what peak shaving means?

Also when I started the setup configurations I first updated the firmware for the cerbo and multiplus

ess settings

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Answer 1 · 2024-06-21T06:37:51Z

Alexandra answered · Jun 21 at 06:37 AM

@mfred68

What battery bank do you have? It is likely the one limiting discharge.

On the peak shaving question... Is your battery, in the screen shot, above the min SOC? If it is, then doesn't apply to the system right now.

Peak shaving is not for long duration heavy draws. Otherwise your system would draw to nothing instead of maintaining the reserve set.

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Alexandra ♦ commented · Jun 21 at 06:45 AM

From the blog article...

How does it work?

The system monitors the current at the meter, and when needed engages to keep that within the configured limits:

to prevent overcurrent during export, system limits solar production and battery discharge.
to prevent overcurrent during import, system limits battery charging.

This part applies to your set up right now...

to prevent overcurrent during import because of loads, system will assist using battery power. (As long as battery permits this, of course).
when the SOC has dropped more than 5% below the configured ESS minimum SOC, the battery will be recharged from the grid as soon as the loads drop sufficiently to allow for charging.

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mfred68 commented · Jun 22 at 09:03 PM

I have a 42kw bank, that is 7x 7kw batteries linked in parallel. The batteries bms can discharge at 100a each. So not sure why the wattage is limited before the grid kicks in.

Any suggestions what could be wrong?

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Answer 2 · 2024-06-23T17:29:21Z

mfred68 answered · Jun 23 at 05:29 PM

Is it because the minimum soc is set to 15% And its already very close to it?

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