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sam-carleton asked

Accurate monitoring of DC power consumption

I have a pretty small Victron system installed in my travel trailer:

  1. Cerbo GX & Display
  2. Victron Smart Batteries
  3. Lynx input and distributor
  4. Lynx Smart BMS
  5. two Multiplus for the 50 amp service

I just added a SmatShunt to from the Lynx Distributor to the RV DC system:

img-0118.jpgWhat is up with the difference between the estimate and what the Shunt is showing? Is that what things like the Cerbo, three MPPT's, Multiplus (even though they are off), are consuming?

I do have GUI Mods installed, is there any way to get the system to show both on the main page?

cerbo gxSmartShuntpower meter
img-0118.jpg (157.5 KiB)
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Alexandra avatar image Alexandra ♦ commented ·
Is your shunt configured as a DC meter? Looks like the mod isn't drawing its information from it.
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sam-carleton avatar image sam-carleton Alexandra ♦ commented ·
I do have it configured as a DC meter, not a battery monitor. I assumed I would have to go into the Cerbo somewhere and tell it what type of DC Monitor it is, but I have yet to find that while poking around.
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pwfarnell avatar image pwfarnell sam-carleton commented ·

You tell the SmartShunt what it is measuring using Victron connect, choose from things like DC system, wind power, fuel cell etc. etc. In your case it should be DC System if it is to the RV DC loads. The GX also needs the "Has DC System" enabled on the System Setup page.

/pg/SmartShunt/en/all-features-and-settings.html#UUID-4d8c0755-7f10-f76d-494a-26f9745051bf

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sam-carleton avatar image sam-carleton pwfarnell commented ·
Thank you, I think I had the shunt set to Generic Load, not DC System. I made the change and all is good!


Now, how can I see how much overhead the two Multiplus actually use?

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pwfarnell avatar image pwfarnell sam-carleton commented ·
Try some math depending on your system. The Lynx BMS will give total ex batteries, your new SmartShunt should capture all DC loads if set up right, you do not mention solar. With the inverters at idle without shore power connected they will be using the difference between the Lynx and the SmartShunt. The one issue I do not know is if the Lynx BMS measures the Cerbo current if connected to aux.
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pwfarnell avatar image pwfarnell pwfarnell commented ·
Or the current taken by the contactor because if it includes the BMS overheads and Cerbo then it will not be possible to get an accurate answer unless you take the datasheet values for these.
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kevgermany avatar image kevgermany ♦♦ sam-carleton commented ·
It depends where the shunt is in the system. You might need a second shunt in the feed to the Multiplus.
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sam-carleton avatar image sam-carleton kevgermany ♦♦ commented ·
Yea, the current shunt is between the Lync Distributor and the RV. Right now both Multiplus have two negatives, for a total of four. Because of this, I am thinking I am not going to put a shunt on them, but if I did, how would that be setup? Would I need to use the SmartShunt 2000A so each wire had its own connection?
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