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jpika avatar image
jpika asked

30-50% from the grid in summer - can't victron do better that that?

Hello, simmilar questions have already been asked here, I reviewed them but with no meaningful conclusion. My situation:

  • 3x victron multiplus II 3kW,
  • Grid set point = 10W.,
  • cerbo
  • 10 kWh pylontech batery
  • Energy Meter ET340 (3 sec delay between START of 2kW load and the change of Energy meter values on the console, TURN OFF of the load has a response time a bit shorter : 2 sec)

battery full, nigh time,

between midnight and 3am. total consumption of the house 0,6 kWh (fridge, small electronics charging devices, etc), power pulled from grid 0,3 kWh; this is 50%

between 3 am and 6am (single phase water heater turned on), house consumption 5,2 kWh, power pulled from grid 1,2 kWh; this is 23%


I want to minimize the power pulled from the grid. Can anyone help please?

Dear @pablosol2 yoou seem to have had very similar problem. Did you manage to solve it?

ess grid setpoint not reached
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6 Answers
chrigu avatar image
chrigu answered ·

A Multiplus 3000 is rated at 3000VA not 3000W. Its rated at 2400W at 25°C.
So if the water heater pulls 3000W, then the missing 600W will be supplied from the grid.
The other two Multiplus cant help in this situation

Check the water heaters elements, theres a chance they can be rewired for three phase, or at least two phase. So instead of two heating elemnts in parallel on 230V you will end up with the two in series on 400V. Their combined power will go down a bit, but at least you would use two phases

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jpika avatar image jpika commented ·

Thank you but the heater is 1.5 kW only, Single phase. I checked it. The other 2 phases are not connected. An original heating element is used - designed for a single phase. What is the reason for that large pull in the interval 0:00-3:00 (as described in my initial information) ?? - in this interval the heater is not on the scene at all.

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nickdb avatar image
nickdb answered ·

Is this a 3-phase config, or 3 parallel inverters. The latter adds many variables into the environment as well.

Grid use happens for specific reasons - derating, overload, imbalances etc.


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jpika avatar image jpika commented ·

3-phase config.

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atebee avatar image
atebee answered ·

How are you metering the grid? Some of the grid meters are know to have quite slow reaction times to changing loads.

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jpika avatar image jpika commented ·

I measure it by Energy Meter ET340. I updated the measured response time to my original post

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Duivert NL avatar image
Duivert NL answered ·

If you have set it up as ESS you can use scheduled charging to go “off grid” at night time, when we had a smaller system i used that in the same way as you,


But as stated before a good fast grid meter will also help

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jpika avatar image jpika commented ·

I am affraid this will not be possible as not all circuits in the house are backed up.

I use Energy Meter ET340 and I updated the measured response time to my original post.

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Craig Chamberlain avatar image
Craig Chamberlain answered ·

You say your grid set point is 10w which means it’ll be importing at 10w minimum. It needs to be -10w to maintain a slight export balance and you could increase this to -50w or more to offset any inaccuracies in grid power metering.

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jpika avatar image jpika commented ·
Hello, thanks, in the meantine I tried different values each day: +10, 0, -10, -50 and the graphs just do not show this. It looks like this setting is ignored. In the documentation I read that this value is to be maintained by the ESS in the self-consumption mode. Is it possible that my PV is working in a different mode in which the grid setpoint is just not taken into account?
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phoenix avatar image
phoenix answered ·

There are many factors at play. Where are your figures coming from and how accurate are they? Calibrated instruments? 10%? I've played around adjusting the grid set point from -10W to +10W over a number of nights. On my system +10W will mean I lightly export using an external CT. The control electronics is doing a very clever thing trying to null consumption via import and export. It's not perfect, particularly with small loads. As @Duivert NL says, it's best to go off grid at night.
Have a look at your battery consumption during the same period. Each MP will be taking 10W/hr, so efficiency is worse at small load.
My system is single phase MP II 3000 latest FW, ESS setpoint +10W. Last night my overnight consumption 00:00 to 0800 was 566Wh (independent calibrated monitor <+/-2% error) and I bought 11Wh (smart meter) I wasted ie over-injected 32Wh of battery. Battery consumption was 693Wh. The unaccounted ~100W is probably the MP consumption and inverter efficiency. I actually don't believe the figures are that good and my calibration around 0W needs attention. Still, I have a baseline to work from.
I think you need more data, and more accurate data, before you start saying your system is poor.

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jpika avatar image jpika commented ·

As I can not go offgrid at night I need to find out whether cca 23% of pulling from the grid is typical or whether something can be done to reduce this number which seems to me too high (daily average, not reaching the minimum SoC) Even if there were a slight measurement error, even 20% of pulling is still too much for a summer day. Or even pulling about 50% pulling at night, when no real load happens and the battery is full.

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