Smart shunts crazy readings

DIY
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1

Hi Guys I have a system installed in an RV with the usual solar, tow charge, multiplus I etc., just lately the smart shunt is showing crazy readings.
Two days ago it was showing a discharge of 500W and today the discharge has risen to 1100W. Both readings must be false as all of the loads have been disconnected. Touch screen is showing the battery at 0% but the multiplus is is showing float. Not sure what it could be.

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2

That looks to me to be bad data. Is the VE.Direct cable from the shunt to the GX running past any active gear that could be spewing a lot of RF? things like microwaves, poor quality phone chargers, ballast from fluorescent lights, that kind of thing.
Other things to try;

  • swap the VE.Direct cable. The signal rate over ve.direct is very low, and its a near bulletproof serial signal protocol that can run over almost anything, but there still could be a fault with the cable or someone jammed it in a door hinge or stuck a staple through it.
  • Change the ve.direct port on the GX
  • Victron shunts generally never need calibration, but maybe someone tried to calibrate it and completely messed it up??? (calibration is covered in the shunt manual )
  • sometimes relying on a chassis negative that looks fine but isn’t actually attached to the chassis can yeild strange results.
  • Do you have aluminium bus bars? weird results
  • Read @pwfarnell post here
3

All started with the display not displaying so we unplugged the Cerbo GX power, then it started to work. Since then the shunt has gone crazy. The RV has no microwave or phone chargers etc., near the cables.

4

Moisture on the SmartShunt or in the VE Direct port can also cause problems.

To check if it is a comms issue to the Cerbo or a SmartShunt issue connect to the SmartShunt using Bluetooth on the VictronConnect phone app. If the phone app is reading OK then it is a cable / port issue.

Here is a link to the pre RMA for battery monitors, you could work through the shunt related items.

5

Thanks I have remotely connected to the shunt and it was reading 0% as well. This system was working and now it has decided to do this.

6

Is it also reporting the odd power flow on the app. If so it is time to check the physical condition, is it wet, corroded, damaged, loose etc and if it is all sound then contact your seller / dealer as it has gone wrong.