Smart shunt not reading current

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jbyers281 asked May 1, '21

Smart shunt not reading current

I have a Smart Shunt 500a connected directly to the negative terminal of my battery from “to battery minus” side of the smart shunt. (There are no bus bars or other items between battery and smart shunt.) The “to system minus” side of the smart shunt is connected via a bus bar to the Victron multiplus box, dc distribution box and ground. As far as I can tell, the system has 2-3a coming in from shore power (this is based on a reading from my EMS box). All ac and dc circuits are disconnected, so I’m assuming the battery is charging. Current voltage on the battery is 14.38. I am reading through the smart shunt 0a, whether I am testing items on the dc circuit or just charging. Shouldn’t there be some amount of current reading?

BMV Battery Monitor Venus OS SmartShunt

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seb71 commented · May 01, 2021 at 05:12 PM

Yeah, the current should not be zero on those conditions.

The “to system minus” side of the smart shunt is connected via a bus bar to the Victron multiplus box, dc distribution box and ground.

Is the negative terminal of the battery also grounded (maybe from before installing the shunt)?

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jbyers281 seb71 commented · May 01, 2021 at 05:19 PM

The negative terminal of the battery is not grounded. The only lead on the negative side of the battery is from the smart shunt to the battery. Grounding on the negative side of the dc circuit is from the bus bar.

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seb71 jbyers281 commented · May 01, 2021 at 05:25 PM

Try a SmartShunt "reset": disconnect the wire coming from the battery positive terminal and connect it back. Not sure if this will help, but it is easy to do.

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jbyers281 seb71 commented · May 01, 2021 at 06:05 PM

Just tried your suggestion. No luck. Still reading 14.4v but no current.

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seb71 jbyers281 commented · May 01, 2021 at 06:39 PM

Can you post a screenshot with the "History" tab from SmartShunt (in Victron Connect)?

Edit:
Also, is the positive wire connected in the "VBatt+" (and not in "Aux)?

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jbyers281 seb71 commented · May 01, 2021 at 06:56 PM

We are connected to the Vbatt +.

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df02ddf4-81c4-42e3-acdb-75d5eecdf3ec.png (185.4 KiB)

goodoz commented · May 04, 2021 at 04:39 PM

Are you sure your charge current is flowing "through" the shunt and then into the battery (and not directly to the battery while bypassing the shunt)? From negative battery post > Batt side of shunt > Load side of shunt to bus bar. Now, connect both charge line negative and load line negative to the same bus bar. That should fix you up...if not, there's a problem with the shunt.

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Answer 1 · 2021-05-01T19:05:43Z

seb71 answered · May 01, 2021 at 07:05 PM

One more thing to try:

disconnect loads, turn off AC power input, turn off the inverter, disconnect chargers;
disconnect the wire from "Load Minus" side of the SmartShunt (so now the only thing connected to the battery is the SmartShunt);
using VictronConnect, go to Settings (cog wheel), click/tap on the 3 vertical dots and then on "Reset to defaults";
then go in "Battery Settings" click/tap on the "Calibrate" button from "Zero current calibration";
check that the curent is 0A;
re-done your other battery settings from SmartShunt (battery Ah, charged voltage, etc.);
connect the "Load Minus" wire back (but pre-charge the inverter capacitors before that);
test if it is working now.

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jbyers281 commented · May 01, 2021 at 07:38 PM

I think it was a bad battery. We tried your suggestion on the battery we had NOT been using. Not sure if our battery was the issue or the rest helped, but it’s working now! Thanks!

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seb71 jbyers281 commented · May 01, 2021 at 07:40 PM

Well, try with the "bad" battery again.

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