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Florian avatar image
Florian asked

High self consumption of Victron ESS

Hello,
I've build a 3 phase ESS using 3 Multiplus-II/48/3000, a Cerbo GX and 3 Pylontech batteries. The already existing Fronius Inverter was detected correctly and the system now regulates to 0W consumption from the grid. Perfect so far!

But I do not understand why it draws on average 90W more from the battery than the actual AC loads consume.
According to the Victron Datasheet the MP should consume 11W each, which brings me to 33W in total. Adding a few W for the GX device and considering 95% conversion efficiency I get 50W top.

Can anyone tell me where 40W get lost?

BR, Florian

Here two screenshots from the VRM portal:

pic2.png


pic1.png

victroninverter current draw
pic2.png (92.3 KiB)
pic1.png (150.5 KiB)
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2 Answers
Jason - UK avatar image
Jason - UK answered ·

@Florian Any transfer of energy from AC to DC, or from DC or AC has losses. As a rule of thumb, the losses are 10%. In realistic terms, with my own Multiplus, the charger is 95% efficient, and the inverter 89% efficient but there are so many factors that affect the efficiency of the system. You will have this with any inverter or charger, and the losses are in the form of heat energy. The below link is a similar post to yours.

https://community.victronenergy.com/questions/247348/what-is-baseline-ac-current-consumption-of-multipl.html?childToView=247397#answer-247397



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Florian avatar image
Florian answered ·

Hi Jaso,

thanks for your reply!
That means the self consumption and efficiency data provided by Victron are wrong?!

I recently found one Victron document describing the efficiency of the 3000VA inverter in detail:

efficiency.png

With my 300W AC load, every inverter would draw 112W from the battery, summing up to 336W. But actually they consume 393W, which means additional 57W.

I also found youtube videos of people describing the high power loss of the Victron ESS system.

But I can not believe Victron publishes wrong numbers, do they?



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