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Ben Boger avatar image

Venus OS showing DC power as negative while inverting

I recently put together a new system and as I've been testing and monitoring things, everything is working great but when I look at things in the Remote Console, the dc power seems to suggest its charging the batteries while inverting. I have tested dc connections and Im seeing a consistent 13.2 volts coming from the 24/12 converter, and all 12 volt motors and appliances are working great.


From the Remote Console, the animation seems to suggest that power is flowing from the DC Power into the battery and the values coming from DC are negative. I've attached an image with an example of what I'm seeing.


At the time of this screen shot, the system was disconnected from any power source except the batteries. There was originally a converter/charger but is unplugged from AC power.

I found this question https://community.victronenergy.com/questions/34619/hmmm-color-monitor-shows-negative-dc-draw.html and have read that the DC power is an approximation but I'm wondering if there is something that I am missing in my configuration that would help this number at least show as positive when inverting.



Venus OSdc system
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2 Answers
mrseas avatar image
mrseas answered ·

Double check your "shunt" and verify all circuits are connected correctly.

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I was looking at this today and it turns out, my chassis ground on the negative bus bar seems to be the culprit. I was trying to run a ground from my inverters to the negative bus bar to have that common ground and hopeful avoid a grounding loop. I didn't account for the existing chassis ground on the RV. which I'm now in the process of trying to find.

Michael Riley avatar image
Michael Riley answered ·

Some addition info which may be relevant to you or others.

I also have the same issue with a VenusGX and a Lynx 1000 distribution (shunt) system. The 'value' of this -ve charge changes rapidly on our system depending upon actual load but always with very low loads and around 50w (on 27.1 V typically). My tests seem to show that the actual current across the shunt is the culprit when the 'Set Zero' actual occurs. In other words there is always a load in our system, these being the VE.direct BMS connected to the batteries via the serial bus and powered from this cable and also the Lynx 1000 itself and the VenusGX which is the controller used to actually trigger the 'set' the zero point. Have turned off all other 'loads' via the 'Load Disconnects'. All negatives go to the Lynx Out side and ONLY the LIPO batteries connections (+ and -) connected to the Lynx In. Have played with this over time and eventually unbolted the loads from the LYNX out to ensure no real loads. I generally now 'accept' this small (<50 w) fluctuation and use the battery voltage as my primary measuring of battery charge status using the Victron battery (LIPO 28v) (recommended) parameters. I understand that SOC is a 'calculation' and voltage is an actual reading hence my preference. SOC 'error' grows over time depending upon this 'zero' set point 'reality'. My wish is for a 'button' on the Lynx Shunt which set 'zero' value and could then get it closer to reality. Hope this may assist.

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