question

gabius avatar image
gabius asked

multiplus 2 draw from grid when battery are full

Hi, i just switched my instalation from multiRS solar to Multiplus 2 5000 with a 150/50mppt.

The whole system is controlled by a cerbo gx and pylontech batteries with DVCC.

I setup the ESS ( i think corectly) evrything seemed fine, when battery are 100% it feed grid with solar.

The problem is when i turn something huge, like air conditiner, it seems to draw some high current from the grid. To be clear it work from solar for few sec, then draw from grid, nothing from batteries, even if they are full...

By the way i know that pylontech bms is "stoping charge and discharge" when 100%(it's what was displayed on the Multirs solar), but with the multiplus2 it doesn't display anything so i don't know if its the pylontech bms wich cause this.

-4x US2000C pylontech 50ah each total 100A max charge and discharge

-DIY battery 300ah conected in paralel with pylontech

-Multiplus 2 5kVa

-cerbogx

-MPPT 150/60

All have last firmware (tried beta firmware with cerbogx, doesn't change at all)


Thanks for your help, here a picture of the event

1685110342469.png

Multiplus-IIESSgrid
1685110342469.png (3.0 MiB)
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Mike Dorsett avatar image Mike Dorsett commented ·
Why should pylontech BMS stop "discharge" when the batteries are full?
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gabius avatar image gabius Mike Dorsett commented ·
I have no idea, it’s what was displayed maybe it was a translation mistake.
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Alexandra avatar image Alexandra ♦ commented ·
Use the remote console over local network rather than the VRM. The update times over VRM doesnt always give a good synchronised picture for shorter duration information.
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gabius avatar image gabius Alexandra ♦ commented ·
The info on vrm is good.

I see that he is drawing from grid on an other source(power meter) and moreover the voltage go lower, from 230 to 219v because the cable is to thin.

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seb71 avatar image seb71 commented ·

Yeah, but then where the PV power goes? It's not going into the battery. A part is powering the load (supplementing the power from the grid), but the huge difference can't be explained by inverter efficency. Something is wrong with the measurments or settings.

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3 Answers
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ejrossouw answered ·

Is the pylontech connected via can and the DIY bank not?

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gabius avatar image gabius commented ·
Yes :) only a smartshunt for the diy
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ejrossouw avatar image ejrossouw gabius commented ·

I propose you disconnect the DIY bank as a test and configure ESS to use the Pylontech battery monitor information. Mixing a unmanaged DIY bank with a managed bank is not something I will do.

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Alexandra avatar image Alexandra ♦ ejrossouw commented ·
I would use the smart shunt for the whole battery bank and disconnect comms. Does your diy and Pylontec have the same charged voltages?
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gabius avatar image gabius ejrossouw commented ·

okay i will try, I don’t understand why it should matter, but maybe it’s about équilibration of discharge between the to batteries

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gabius answered ·

Here is a clip of what happened when I turned on my AirC on. Then the AC in is disconnected by the multiplus because of rules when voltage is too low


fullsizerender-copie.mp4 (40.8 MiB)
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gabius avatar image
gabius answered ·


can you assist on this @Guy Stewart (Victron Community Manager) ? Trying to find a solution for a month now, I have no idea anymore


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