Inverters see AC-In voltage and freq, but not connecting to grid

Hello,

I have a Grid-tied UPS setup, using two Quattro 5k’s. It’s worked well for a few months, with occasional outages and recoveries-- very minor ones. Recently, we had our first major outage. The batteries are drained to ~2%, but the inverters aren’t reconnecting to grid!

In the status screens, it shows that it sees AC-In voltages and frequencies that look healthy

I’ve also enabled wide frequency input.
We’ve tried power cycling with the main Quattro switches, resetting the VE.Bus, and I’m at a blank… please help!

We also just noticed the second inverter’s status lights went off and the first unit is flashing status lights between Inverter On and Float–the manual doesn’t have anything listed for this…

Thanks,
Mike

You can find the fault definitions in the victron toolkit app.

This is ve.bus fault 1, missing phase

The original fault is in the other unit.

Btw you should test emergency power at least once per month, when batteries are full. Then have the whole system running on generator for one hour.

Looking at the faults, there is no fault 1 being listed.
Here’s the list of faults.

  • We have had roughly weekly outages with no issues before, but never 24 hrs draining the batteries this much

  • The alarms are making me distrust the VE bus. We’ve tried resetting it a few times, sometimes with differing effects.

  • I was upset with Signature Solar for not providing cables for these connections, but I seemed to have got it to work in the past… Here’s what I understand about the VE bus:

  • There are no terminations, like on the VE Can.

  • We’re using CAT 5E cabling that we had around.

  • I have one cable from each inverter going into the VE bus ports on the GX. Of the cables I had, one of the cables is Cat 6 patch 24 awg, the other is Cat 5e 26 awg (not patch)

Do you have to use patched vs not patched Cat 5?

Other thoughts??
Thanks

Your primary problem ist lost grid, sometimes victron inverters have problems connecting to generators, due to waveform distortions at high charge currents.

Should be solved with firmware v552, so you might try to upgrade.

@mjs333

Hi Mike

The connection on the ve bus is one inverter to the other than then one from the inverter to the GX. (I usually use the master. I don’t think it matters - never tried it anyother way.)

They use straight (also known as patch cables between the gx and the inverters.)

You are correct you don’t need a can terminator.

The system is in float with is strange if it needs a charge.
How is your system programmed?

@Ludo Grid should be good. voltage and frequency are showing all in spec.

@lxonline We tried switching the ethernet cables as you described. Sadly no improvement.

Update:
I reconfigured the units to be independent (turned off any 240V split phase loads). The master unit came back to life, is passing grid power to the loads and charging the battery!!
The second unit is faulted, but I can’t figure out in VictronConnect how to read the fault (using the PC version). We also noted the GX display wasn’t displaying the faults earlier… not sure if related.

I’m hoping maybe it wants a higher battery voltage, and it will come to life in a bit with more battery charge. But I’d really like a way to read the fault…

But its more needed : waveform, noise etc

@mjs333
It will be in fault mode of left as previously programmed (part of a split phase set up) as it is looking for its partner.

Reset to default and see if the fault is still there. Victron connect usually has a banner on it if there is a fault.

@Ludo Understood… wouldn’t the other inverter fault if this was the issue? The other inverter has been rock solid.

@lxonline Correct, we went in and reprogrammed both inverters to be standalone using Victron Connect. It does show a fault, but we can’t see what it is!

To be clear, we disconnected the second inverter from the Cerbo GX (we tried with it connected to the GX and the other inverter disconnected… no difference–faulted either way)

Did you upgrade to 552 ?

Also check this thread

A firmware update is definitely the next move.

Unless you feel you are at the point where there is a warranty claim? Work through the testing in the pre rma form.

Checked firmware versions a few days ago—all updated.

The VE Bus tools is something I’ll try to read the faults. (Sadly I’m doing this all remotely, with a friend at the house… can’t try now)

I will also check a few settings to make sure they were mirrored correctly:

  • Accept wide frequency range
  • Weak AC
  • Power assist off
  • check voltage limits
  • I could have sworn I checked if the AC ripple was triggered, but will do again

With the units independent, it lets the good unit charge the batteries, while the bad unit inverts to supply power to the loads… works okay for now. I just can’t power my 240v water pump.

Thanks for all the thoughts—any more are welcome

The “bad” unit should show why its not connecting…

@Ludo, where do I find the information on why it’s not connecting? We didn’t see a fault, but this one unit is still on inverter only (the other unit working well).

  • I verified the following settings: Accept Weak AC: on; Power Assist: off; Accept Wide Frequency Range: on
  • Voltage and frequency were in-spec, and no errors
  • Here is the display from VE Configure, looking at the VE Bus. Should UMains be orange?

We did notice a few things that caught our eyes. Let me know if these rings any bells:

First, I noticed this tab… I have no idea what this stuff refers to. Thoughts?

Second, we noticed the following in the NS Protection Log. I think this refers to the battery… could be related to how we’re messing with the VE Bus connections to get the two Quattros operating independently for diagnosis… This inverter is operating without comms to the GX, battery, or shunts. My quick google seems to indicate these under voltage entries refer to the battery–which is working fine. Let me know if you all have other thoughts.

Thanks all

No, the errors are in the GRID tab, so they refer to the incoming ac voltage.

And ofc the ac-in should not be orange.

Disconnected you have 120v, as soon as the multiplus tries to connect the voltage breaks down. So there must be a loose contact in the wiring or a defective circuit breaker.

For the checked assistant function you’ll have to check the other tabs on this page

Thanks for the inputs… will check all connections in the morning.

Hi All,

  • Connections were all tight–no change.
  • Interestingly, when we went to tighten the connections, the grid was down… had a 6+ hr outage before we got feedback on if anything changed. But alas, we still have a fussy unit regarding accepting the grid.

We did take screenshots of all the VE Configure tabs. Again, I don’t understand the Virtual Switch, so I’d love help looking at those settings. Of note, now the frequency is also orange… the values look totally fine to me though! We’re still getting the Under-voltage log entries on the grid tab…





More screenshots:





On the final advanced tab, we are not limiting charge to prioritize other energy sources. (just didn’t want another post)

As far as i see you can just as well turn the vs functionality off, as no parameters are set.

Just to try, I’d also swich off weak ac, wide input range, ups. Probably won’t change anything, but worth a try.

And try setting to charger only, then no synchronisation is needed.

The quattro should adjust its voltage and frequency to the grid values, which it clearly doesn’t do.

Maybe @lxonline or @M_Lange have some good ideas ?