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edvanz asked

Cerbo GX Current is wrong but voltage and watts are good???

The watts and voltage are correct but the Amps are way off, this causes an issue for my generator as I set the limit for the generator just below the max amps the generator delivers but Cerbo thinks it is consuming 5 or 6 Amps less than the generator is delivering but the voltage and wattage are perfect inline between the generator /or even shore power and the Cerbo. This causes the generator to go in overload and it trips the shore power all the time. To bypass this behavior I set the limit in the Cerbo 6 A lower than the shore power or the max output of the generator.

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233V is the same as my NL generator 8423W same as my NL generator but the Amps are wrong it should be 36,5A. Same for AC-out L1 also wrong. I thought that with the data the Cerbo has it should provide the right Amps calculation.

What have I done wrong???

Setup is 2x quattro 8000 , 1x Skylla , 2x Mppt 150/70 , Cerbo Gx , Centaur 16

cerbo gx
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4 Answers
edvanz avatar image
edvanz answered ·

And today it is the other way around, it is driving me crazy

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Alexandra avatar image Alexandra ♦ commented ·

Input 11.5 - loads= 327w difference

Loads (6.06 + 3,813 + 1.13 = 11.173 )

Losses due to heat (at loads like that fans will be running) and wiring inefficiencies and load power factor. I assume batteries and dc loads are being measure with shunts and so are accurate not calculated by the system

400ish watts on an 11.5kw draw is actually pretty decent.

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edvanz avatar image edvanz Alexandra ♦ commented ·

and over 1 kw in the first example? which is over 10% off? what I don't understand is that the Victron reported values off voltage and wattage are, let say, correct, so why can't the current be correct? I just should display the inbound values. I have a freq and voltage converter giving exact data. 2 generators from NL giving exact data on voltage and amps produced the amount of kw and voltage delivered matches the Victron shore power or generator input on either AC1 or AC2 in. The voltage also is 100% correct. So why is the Amperage wrong? The importance off it is that the Amperage is the ONLY adjustable value, on the control panel, to make sure the generator or the shore power doesn't go in overload or pop the breaker. When we have limited shore power or run the small generator this amp limiting capability is most important as it stops the overload and/or the shore power breaker to pop. The last one has caused heated discussions between me, defending Victron's data over the marina's shore power meters which always are higher in usage than the Victron let me believe. The difference can be as high as 13A too less and up to 7A too much and this 20A difference makes the Digital Multi Control to manage inbound current absolutely useless.


One thing gets clearer now and that is the situation that, on a let's say 32A shore power, Victron power assists doesn't stop before way lower than the reported Amperage by Victron. ie We need to go down to 24A before power assist stops and charging starts happening and sometimes the other way around and power assist doesn't kick in on time creating an overload on the generator This lets me believe that Victron equipment does know the right inbound value in wattage but calculate the Amperage wrongly and uses that figure to control power assist which than causes all the trouble

@mvader (Victron Energy) Mathijs Vader

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edvanz avatar image edvanz Alexandra ♦ commented ·

Yes correct Loads (6.06 + 3,813 + 1.13 = 11.173 ) is not too far away but since when is 11.173 at 232v = 57.1A??????? In my books that is 48.1594828A let's say 50A would be acceptable :)

But how are they calculating the Line IN Amps? As that is rather important for shore power and generator supply


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cozzmicc avatar image
cozzmicc answered ·

Hi!

I have a similar problem: I'm reading from the CerboGX the values of my Solaredge SE10K via ModbusTCP. The values of the voltages are ok, but the values of the total watts are nonsense. I'm reading the values with QModMaster and my external Energy-Optimizer (Smartfox Pro2). Both the same. Screenshots of VRM and Win10. Oh, and beside this, the values of the watts are on an address (+1) not mentioned in the xlsx-file.

Loots of problems...

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Thanks for answers!screenshot-20230701-182158-chrome.jpg


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edvanz avatar image edvanz commented ·
I see, don't understand nobody from VICTRON jumps in and explains why this happens or some experienced dealers. Maybe we should post this in the development section too
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edvanz avatar image
edvanz answered ·

Hi Alexandra,


I know this and I am very thankful for the volunteers to try to help out but some dealers can't answer or don't take the effort to find out the answer and here sometimes Victron staff and the better dealers are helping out. This problem is not a new problem Brians post from 23 March is indicating the same problem and he tested it and found out that is only happens when you have parallel products in your system

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nickdb avatar image
nickdb answered ·

The current reading hasn't aligned for a long time, if ever, and there doesn't seem to be intent to change it for various reasons.

You are trying to compare apparent current with real power, these won't align.

The multi is not a particularly accurate measurement device, nor is it very quick, so external meters will always be better than the internal one.

There are timing delays within the multi and externally so what gets shown on VRM, via multiple sources, may not originate from the same moment in time and thus won't align.

Yes it is annoying but unfortunately it is the way it is and I don't expect to see it change any time soon.


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edvanz avatar image edvanz commented ·

Thanks, Nick, at least it is nothing I have done wrong but why sell DCM panels to control the intake Amperage and even have support videos about how nice this is for power assist and not blowing the fuse on the shore when you are in a marina? Still don't understand when it displays wattage and voltage correctly why they can't do the math and display the corresponding current

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