question

techmaniac avatar image
techmaniac asked

Sum of powers far out of range (power disappears)

In the VRM Portal as well as on the display the sums of powers is far out of range

700W are consumed but 1600W are fed into the system from solar and battery, which means 900W disappear somehow.

Any clue where this could go to?

deb3a786-95c8-4c7e-8eed-826014bc5f61.png

Another example with the display

9b9da60c-2b88-418c-a7f8-8c5632c0b272.png

VRMdashboard display
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5 Answers
marekp avatar image
marekp answered ·

@Techmaniac

It could be that the numbers you see are not from the same moment in time.

Also you have to "calculate in" the efficiency of the DC to AC conversion.

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techmaniac avatar image
techmaniac answered ·

OK, after some days of watching the display I am pretty sure that it does not show what's really happening. It stays in "discharge" all day even if more than 1kW contantly flows into the battery. The "-" at the battery indicates a "negative discharge"=charging.

The SoC is correctly calculated and the battery full by the end of the day so...

- either the values/status are simply displayed erroneous and everything is fine in the background

- or the charging is a "coincidence" and the system does not correctly control the devices

or?

Extra info: There is no external current sensor present, only the internal sensing is used. MultiPlus and MPPT with Cerbo in the system.

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@Techmaniac

The "-" at the battery indicates a "negative discharge"=charging.

I do not understand what you are saying.

If current at the battery has negative value it means that battery is discharged.

"Bulk", "Absorption" and "Float" are charging states.

Can you show us a diagram of your system?


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Sure. Pls also see my new reply in the main thread

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techmaniac avatar image
techmaniac answered ·

Finally, a colleage of mine had the correct answer: It is the point of view of the MultiPlus which is displayes. From his point of view, he is always discharging something no matter if it comes from the MPPT or the battery.

So the battery shows a discharge with a genative current which is practically charging.

Quite misleading and from my pov a bug in the programming as at least the battery should display "charging". Maybe they fix it in a future release.

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@Techmaniac

You can fix this "problem" by installing SmartShunt.

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trevor-bird avatar image
trevor-bird answered ·

Hello @Techmaniac , as marekp says it seems the missing component to your system is the Smartshunt. Each component of your system reports what it knows to be the situation but CerboGX does not know what the current is in or out of the Battery. The battery is discharging as far as the Multiplus is concerned (and that is reported) but the MPPT is actually charging them. The only way for the system to know that is for the current into or out of the battery to be monitored. That is achieved with a Smartshunt. If you install that your visual representation of what the system is doing will be resolved.

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Thank you very much. I just ordered the smartshunt, will be installed by the end of next week and I‘ll keep you updated!
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techmaniac avatar image
techmaniac answered ·

Okay, I think I got it:

I bought a smart shunt and inserted it into the system as described. In the settings I then selected in the DVCC common current and common voltage. And I think the most important setting was that the smart shunt will monitor the battery, not the inverter. Now the display shows correct values.

1a0ed19f-9dc3-465b-9a13-dbcc01dd3f7e.jpeg

e4e2b1e1-49ef-4ac5-a0dd-c167d8ba8e15.jpeg


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