FOX inverter H3-5.0-E

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Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

Since December '23, I have owned a photovoltaic system from FOX. The inverter model H3-5.0-E with battery storage shows the following behavior:

After dark and discharging the battery to the defined SoC Grid value, the inverter attempts to restart every 15 seconds.

This is indicated on the inverter by the sequence of the following displays:

1. "Starting..." - 2. "Waiting..." - 3. "empty display"
This is accompanied by multiple clicking sounds.
During this sequence, the battery is discharged below the SoC value - about 1% per 1,5 hours.

This behavior only stops when it gets light again and the solar modules start generating power.

Is this behavior normal for the FOX inverter model H3-5.0-E (which I do not expect)?
Does anyone know how I can stop this strange behavior?
Dave Foster
Posts: 763
Joined: Thu Oct 13, 2022 7:21 pm

Is it not tied to the grid ?

What you are describing is what would happen when there is not enough solar to run the inverter, at which point it turns to the batteries to supply power - when the batteries reach their minSoC setting the BMS would normally request charge from the inverter (via the grid).

In this case it sounds as if your inverter is not able to charge the batteries - which would only happen if it wasn’t connected to the grid, or there is a fault in the charging circuit - either way the inverter no longer has enough power to avoid being in standby which is what it is doing in the ‘Starting, Waiting, cycle’ as it is waiting for sufficient DC power either from the batteries or from solar to start up.
Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

The inverter is connected with the grid.

But I don't want to use expensive power from the grid to charge the battery.
The battery should be charged only by solar.

The inverter work model is "Self-Use". and charge from grid for the battery is not enabled.
Dave Foster
Posts: 763
Joined: Thu Oct 13, 2022 7:21 pm

If the inverter is connected to the grid, as soon as the battery hits minSoC - it will maintain the battery at that level with a small of amount of charge - this in turn keeps the inverter from going into standby which is it’s normal behaviour.

If the battery isn’t being maintained when it gets to minSoC, there could be a problem with the inverter charger - i’ve never tried to see whether setting the MaxSoC setting to the same as minSoC does, but that might stop it maintaining the batteries. - What is you MaxSoC set to ? (Note unless you have agent access you may have to look at this setting at the inverter panel).
Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

Thanks for your answer.

Max SoC = 100%

In the user manual guide I havent found a good description or a preferred value for this parameter.

Is Max Soc only the charging limit of the battery for charging from the grid or has it also an influence of charging the battery from solar?
Dave Foster
Posts: 763
Joined: Thu Oct 13, 2022 7:21 pm

MaxSoC is only used for grid charging (solar ignores it), it's meant to be used to limit the amount of charge you get from the grid (if you have a charge period set overnight on a low tariff) so that there is some spare left to be filled by solar during the day.

For some reason something is stopping the inverter keeping the battery maintained at minSoC which is why it goes into standby... i've never seen that before - could you try setting a charge period in the app (only for a few minutes) with the charge from grid switch on, what should happen is it should start charging the battery from grid as soon as the charge period begins - that will prove whether the charger is working.
Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

I've enabled the charging time from 3 to 6 o'clock this morning with SoC on grid = 15% and max grid = 25%.
Since 5:18 this morning the app shows status Offline.
So I have no Information about the current behaviour in the app.

It seems that the charging from grid caused the Offline.

Can you please tell me

How can I change the mode in Online?
Have you an idea what is wrong with the charging from grid possibility?
Dave Foster
Posts: 763
Joined: Thu Oct 13, 2022 7:21 pm

Can I just check what you meant by max grid at 25% ?

Your 'minSoC' and 'minSoC on grid' settings from what you have said should both be set to 15% and 'maxSoC' should be left at 100%.

I think the offline event is your inverter going into standby, which suggests that either the charge didn't work or it ran out of battery power before it got the chance to charge.

With the settings for minSoC and maxSoC as above - can you try a force charge from grid during the day, or early evening whilst it is still on-line.

The charge only needs to be for a few minutes, just to prove that it can actually charge from grid.
Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

The screen of the inverter is shows following values
  • this morning, 9:55
    Power 62W
    SoC = 17%
  • 16:20
    Power 310
    SoC 97%
  • 16:45
    Power 500W
    SoC = 100%
It seems that the inverter is running, but the battery is not used.
It is a rainy day and I do not expect SoC = 100%.

The app still shows no data since 5:18, state = Offline.

I've changed maxSoC from 25% to 100% as you recommend.
Dave Foster
Posts: 763
Joined: Thu Oct 13, 2022 7:21 pm

Without seeing your solar generation as well it is difficult to tell as the inverter load seems low and even on a rainy day at this time of year it wouldn’t take much solar to be able to charge your batteries.

Which batteries and what capacity do you have?.

Once it is too dark to generate solar, the information on the display will be more helpful as the battery has to be used to cover the house load.

The inverter showing as off-line suggests the datalogger has not re-connected to your wifi after it went into standby yesterday - that is usually corrected by unscrewing the collar, pulling the datalogger out of the inverter and plugging it back in.

Is this a recent installation, or one that has been installed for some time - from what you have said I think you should contact your installer and ask them to check the system as it is not operating correctly when the battery reaches minSoC, you would expect it to do small maintenance charges that keeps the batteries at minSoC but more importantly stops the inverter from powering down and going into standby - that really shouldn’t happen on a healthy system.
Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

Here is the description of the system
  • Inverter H3-5.0-E
  • Solar modules 4.5 kWp
  • Battery Cube ECS2900 5 kW
  • EPS
  • Commissioning 30.11.23
Since commissioning, the system shows the above described 1. "Starting..." - 2. "Waiting..." - 3. "empty display" behavior.
For 3 months I have therefore been switching the battery off in the evening and on again in the morning.
My installer is of the opinion that this is normal behavior.
Dave Foster
Posts: 763
Joined: Thu Oct 13, 2022 7:21 pm

You shouldn’t switch the batteries off, this is a hybrid system and it needs the batteries to be on to keep running - if you turn off the batteries the inverter will go into standby and repeat the sequence you mentioned.

With the batteries left on, if the system still repeats this sequence, there is a fault.
Mivera
Posts: 7
Joined: Mon Apr 01, 2024 2:17 pm

Your hint to unplugg and replugg the datalogger helps.

Also the loading of the battery in the night ends succussfully without errors.

So it seems, that you have found the incorrect setting, many thanks.
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