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questionableturkey avatar image
questionableturkey asked

ESS not working, multiplus doesn't invert or charge.

I'm hoping someone can steer me in the right direction here as I'm tearing my hair out:

I have a Multiplus 2 connected to the grid on AC In. I have a battery connected with BMS talking on CAN, and I have an external CT on the main AC In to the house which is connected to the external sensor input on the Multiplus. I have nothing connected on AC Out and the whole thing is controlled by a CerboGX. So configured like this:

Grid--->CT--->House--->Multiplus---->Battery

I am attempting to have the Mutliplus support the AC loads in the house as long as the grid is connected, and I intend to use scheduled charging to charge the bank at night. Eventually a DC coupled solar system will come along, but not yet.

I have two problems that may or may not be related.

1. The Multiplus does not invert back to the grid or charge the batteries via Keep Charged, or via Scheduled Charging. After reset it sits at Bulk for a while before falling back to Passthrough.

I can make it happen manually. If I control it in Mode 3 and send the appropriate commands directly then it'll happily charge and discharge the battery. Further, whilst in Mode 1 if I write a value to dbus channel Hub4/L1/AcPowerSetpoint then it springs to life and acts as expected for 60 seconds - after which it falls back to passthrough.

I cannot fathom what is going on here. The Multiplus appears on the console as being in "external control". Not sure if this is right. Seems it's waiting for external commands? Not sure how the control loop works - would have thought it'd be internal to the Multiplus.

2. The Multiplus is reporting the same current use on AC In as it is on AC Out. The CerboGX reports that the AC coupled loads are zero. This isn't right - there are no loads on AC Out so I don't know why the Multiplus is reporting it like this.

Screenshots below. Any help much appreciated.



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Multiplus-IIESS
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7 Answers
Rob Duthie avatar image
Rob Duthie answered ·

Hi

Have you installed the correct grid codes using VE Configure and assistants ?

Regards

Rob D

NZ

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questionableturkey avatar image
questionableturkey answered ·

Thanks Rob.


Yes, this is set up correctly (I think). I've also taken it back to defaults and set up again from scratch - no change in behaviour.

I have though continued to read since I posted the above. I think I might have mis-interpreted the correct settings for the CT. This is not a "External Grid Meter" - turning this off in the ESS settings menu brings the Multi into bulk mode. It will now charge the batteries, but continues to not export to the grid.

I've noted that there is a dbus message Hub4/DisableFeedIn that is set to 1. Setting this to 0 starts the Mutli exporting, but something resets it to 1 pretty promptly. Any ideas what might be doing this?
Also, with External Grid Meter set to Inverter/Charger the CerboGX mimic display is no longer correct.




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ejrossouw avatar image
ejrossouw answered ·

Yes, grid metering should be inverter as the CT replaces the internal one. Is the CT the right way around? Is it the wired version or older din plug? (The older din plug had an issue and it was advised to push it in and out a few times to 'dislodge' a stuck connector.) If the wired one, you may have the wires wrong? Not related, but the battery voltage is high for a typical LifPO4 suggesting an EV battery?

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questionableturkey avatar image
questionableturkey answered ·

It's a wired one, and I did get the CT backwards first time round. I'm confident it's correct now though.

The battery is a 16S config of Nissan Leaf cells. Possibly a touch high on the volts, but trying it out for now.

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Rob Duthie avatar image Rob Duthie commented ·
14 is the sweet spot
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questionableturkey avatar image
questionableturkey answered ·

For anyone finding themselves here from Google, this was my solution. Two dbus channels:

com.victronenergy.settings /Settings/CGwacs/MaxChargePercentage (Enable/Disable charger)
com.victronenergy.settings /Settings/CGwacs/MaxDischargePercentage (Enable/Disable inverter)

Note that the MaxChargePercentage and MaxDischargePercentage paths are represented as percentage, but should be used as on/off switch (0: off,100: on).

Setting both of these to 100 brought the system to life. Unknown why they were at 0 to begin with.

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stormdust avatar image
stormdust answered ·

I have a similar problem, ess is stuck at recharging and dont swap back. How can i see the values there and set them?

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jindrich-janek avatar image
jindrich-janek answered ·

Hello,

I had a similar problem after replacing Multiplus II 3k with Multiplus II 5k.

Modbus parameters are stored in Cerbo GX.

I solved everything by resetting it to default Cerbo device and configure again.

Instructions are here: https://www.victronenergy.com/media/pg/Cerbo-S_GX/en/reset-to-factory-defaults-procedure.html

Jindrich

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