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ford-donald asked

SmartShunt DC Meter Settings Negative Readout

I've added a secondary SmartShunt to my travel trailer system for the purposes of measuring consumption on the DC side of the installation. I am getting odd readings that don't fit intuition.

Question is: when I set the shunt to DC Meter Mode + "Generic Load" or "DC System" I get negative output numbers on the meter, causing Cerbo to show the DC system as a supply to the system (little dots travel from DC System to Battery). Intuition says this 24/12v DC converter should be a load and it certainly is the DC System as every12v circuit is downstream from the Orion 24/12. If I change the mode to DC Meter + "Generic Source", the reading flips from negative to positive and things look correct in Cerbo (dots travel from battery to DC). What are the definitions of a Load, Source and System in this context?

My setup is a 24v battery and inverter system with an Orion DC-DC 24/12 stepdown device to supply 12v for the trailer. I have wired the Orion as the only appliance downstream from the shunt as a 24v device with "stuff" attached to it, I only care how many amps the stuff wants.

Thus:

Trailer ground -> SmartShunt "TO BATTERY MINUS" bolt

SmartShunt "TO SYSTEM MINUS" bolt -> Orion 24/12 stepdown negative post

24v supply from batteries -> SmartShunt 24v input of Orion DC-DC

Orion DC-DC 12v output -> trailer 12v DC fuse panels

cerbo gxSmartShuntorion dc-dc
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Hi @Ford Donald

Do you also have a shunt or BMV as battery monitor in the system?

What is the firmware version of the Cerbo?

Kind regards,

Thiemo van Engelen

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ford-donald avatar image ford-donald Thiemo van Engelen (Victron Energy staff) ♦ commented ·
I do have a BMV shunt in the system, connected between the battery bank and the rest of the system. Cerbo is at v3.32.


24v battery neg -> BMV-712 shunt BATT

BMV-712 SYSTEM -> trailer chassis & system grounds -> SmartShunt in DC Meter mode -> Orion 24/12 ground

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1 Answer
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kevgermany answered ·
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