question

ffmg avatar image
ffmg Suspended asked

Grid is up, battery is charging, Solar is producing more than load ...but I am still using the grid.

Hi,

I was hoping someone could help me understand what my system is doing ...

  • My solar panels are producing +2100W
  • My load is +1500W
  • My battery is at 67% and charging, my battery SOC is 55% and active SOC limit is 60%
    So the battery is charging at +700W

This all makes sense to me, but the part I don't understand is why I am _also_ drawing 300W from the grid.

I have more than enough to handle the load and charging the battery.

I have noticed this pattern over the last few weeks ... regardless what I am doing , if I am charging the battery I am always drawing something from the grid ... no matter how well my panel are doing, (they sometime go over 4900W).

The only time I am sending anything back to the grid is when the battery is 100% full, regardless what my battery SOC is.

Is it expected behaviour?

Edit:

Since my post I thought I would add my VRM screen to demonstrate.

As you can see below, I have more than enough power coming from the panels, so why am I drawing 242W from the grid.

1706090019157.png

MPPT SmartSolarbatterygrid
1706090019157.png (61.7 KiB)
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phoenix avatar image phoenix commented ·
Your screenshot shows external control. On my ESS I don't have that.
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ffmg avatar image ffmg phoenix commented ·

Not really sure why it says that ...

1706183659870.png

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3 Answers
luphi avatar image
luphi answered ·

As long as SOC is below (active SOC limit + ~3% hysteresis), whole Solar Power is used to charge the battery.

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ffmg avatar image ffmg commented ·

But as I mentioned, it is not below the active SOC limit, at the time it was above by +7%

Since my post my charge went up to 77% and my load is about the same.
My PV Charger is now +4600W

But as you can see below, I am still drawing 242W from the grid.

My question is why, why would I draw anything at all when I have more than enough to charge the batteries and handle the load.
1706089915144.png

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luphi avatar image
luphi answered ·

What is your grid set point?

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ffmg avatar image ffmg commented ·
It is set to 50W, (I assume it is the default as I did not change it since the install)
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luphi avatar image
luphi answered ·

What type of inverter do you have and how does your ESS configuration looks like?

What parameters (CVL,CCL) are set by your battery?

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ffmg avatar image ffmg commented ·

I have 2x MultiPlus-II 48/5000/70-50

As mentioned in my original message, my battery SOC is 55% and active SOC limit is 60%

1706179903423.png

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