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VMII clone 5.5kw behaving strange


geert
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I assume that Axpert is the original manufacturer, too late, I did not know and unfortunately I bought this clone (blue-white color chassis) from Aliexpress.

My believe is that the inverter came broken:

I have no batteries on the inverter. When I connect PV power (+-4kW), AC in and AC out, I measure that the inverter is only taking power from the grid, not from the PV.

The inverter is in SOL mode, but never disconnects from Grid. When there is no load, the inverter is using +- 2A, which is around 460watts, the manual says that it should be consuming < 35W.  When all is connected, including PV power and I disconnect the AC input, the load goes off. I tested with loads of 100-200-500-1000 watts.

The inverter is showing no errors on the display. I opened the inverter, checked all the cabling and was looking for any short or burned components, but all looks (measures) good.

The company refuses to give me a replacement, even after proving that something is wrong with the inverter. (made lots of videos for them and lost a week of time, arggggg)

It is running firmware 20.10

Any ideas would be very very welcome! Thanks in advance.

 

 

 

 

 

IMG_20220621_230640.jpg

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Must admit, this the first time I have seen a clone with the High voltage Solar Charge Controller. Sorry about this purchase. Maybe try to contact AliExpress direct. Maybe you get some resolution. 

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8 hours ago, geert said:

I assume that Axpert is the original manufacturer, too late, I did not know and unfortunately I bought this clone (blue-white color chassis) from Aliexpress.

My believe is that the inverter came broken:

I have no batteries on the inverter. When I connect PV power (+-4kW), AC in and AC out, I measure that the inverter is only taking power from the grid, not from the PV.

The inverter is in SOL mode, but never disconnects from Grid. When there is no load, the inverter is using +- 2A, which is around 460watts, the manual says that it should be consuming < 35W.  When all is connected, including PV power and I disconnect the AC input, the load goes off. I tested with loads of 100-200-500-1000 watts.

The inverter is showing no errors on the display. I opened the inverter, checked all the cabling and was looking for any short or burned components, but all looks (measures) good.

The company refuses to give me a replacement, even after proving that something is wrong with the inverter. (made lots of videos for them and lost a week of time, arggggg)

It is running firmware 20.10

Any ideas would be very very welcome! Thanks in advance.

 

 

 

 

 

IMG_20220621_230640.jpg

Is the issue not that there are no batteries connected to the inverter?

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Hi Leshen,

Thanks for replying. I was thinking the same. However they (seller) keep on saying that the inverter should behave normal without batteries.

I don't know what their perception of "normal" is :)

I found on this forum the firmware VMII 5K_3K MAIN_V2043, someone know if that would be a good candidate for a firmware upgrade?

Would a firmware upgrade be advisable?

 

Thanks !!!!

 

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Hi Jacques,

Thanks for your reply :)

I  agree, I guess the chance would be bigger to brick the inverter than to upgrade it successfully. Anyway I am also struggling to get a communication via rs232 or USB.

(on my other inverter, rs232 works immediately)

Currently I am not in a position to test it with batteries, unfortunately.

Beside the PV injection problem, I  measure with Amp clamp and with Amp meter that the inverter with or without load is consuming around 450-460W (2 amps-230V)

(with load = load+inverter consumption) No matter which setting I take, it always takes the power from the grid. I never hear any relay clicking...

Any ideas are welcome!

Thanks a lot

 

 

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Some update.

I got the inverter partially working after a "restore to defaults" with Watchpower and configure it again as before.

The inverter injects now solar power to the load.

HOWEVER I always have the inverter pulling 450W from the grid, even with or without load (PV on)

When I disconnect the grid, the inverter remains active and continue to work normally, and sends power from PV to load.

But I cannot afford that the inverter constantly consumes 450W from the grid during the day & night...

 

Any ideas?

 

 

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44 minutes ago, geert said:

Some update.

I got the inverter partially working after a "restore to defaults" with Watchpower and configure it again as before.

The inverter injects now solar power to the load.

HOWEVER I always have the inverter pulling 450W from the grid, even with or without load (PV on)

When I disconnect the grid, the inverter remains active and continue to work normally, and sends power from PV to load.

But I cannot afford that the inverter constantly consumes 450W from the grid during the day & night...

 

Any ideas?

 

 

A simple question. When it pulls the 450W from the grid do you in fact have a permanent load of 450+W switched on?

Edited by Scorp007
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Hi Scorp007,

Thanks for your reply.

No, I have no load connected (output wires off), it is only the inverter that consumes that much.

I just bought a new AMP meter (to make sure), I have the new AMP meter and also the AMP clamp, they both show the same result, around 2 Amps current.

To give you an idea, you take an inverter and just plug into a socket and measure the current it draws, in my case this is 2Amps.

2Ax230V = 460W that is the consumption of the inverter. This consumption of the inverter is always present - even with PV power, load or no load.

Looking at the manual it says that the inverter itself should consume less than 35W, this is about right for most of the inverters ...

I have no idea why this happen, is this a problem with all these models of inverters or could this be a broken electronic part?

:) regards

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3 hours ago, geert said:

To give you an idea, you take an inverter and just plug into a socket and measure the current it draws, in my case this is 2Amps.

2Ax230V = 460W that is the consumption of the inverter.

No, 2 A x 230 V = 460 VA. To find how much power that is, you need to know the power factor. There could be a considerable phase difference between the voltage and current. If the angle is nearly 90°, then the real power drawn will be much less than the apparent power.

Without a battery, the AC input is connected to the AC output (so it's like a grid tie inverter, but it tries not to feed back to the grid). That means that the LC filter is across the inverter AC input. The capacitor causes the reactive current to flow, but does not result in significant real power. 5 kVA models are known to draw some 2-3 A from AC-in, but it's not real power, it's apparent power. These inverters should have an idle power draw of some 50 W, though with clones, that's not certain. If you plug the inverter into a power outlet via a gizmo that can read the power factor, you'll see what I mean. At idle, power factor will be about 10%.

Some clones can't be firmware updated at all. One would think that the clone makers would provide the latest firmware that can be stolen from the internet. Though maybe they need to make changes to it (e.g. to remove the words "VOLTRONIC POWER", and they somehow have source code for an older version. And they're not patch wizards.

19 hours ago, geert said:

The inverter is in SOL mode, but never disconnects from Grid.

This is normal when no battery is connected. The PV input is not stable enough to run loads without AC input to partially take over if there is a cloud or increase in load.

Edited by Coulomb
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Hi Coulomb,

Thank you very much for your clarification, it all makes sense now  :)

I saw in some hybrid inverter manuals that they talk about the pf = 1.0, but I guess that is only the output pf?

 

This makes me think of another question regarding the size calculation of a solar system e.g for a guest house with many A/C units, fridges, etc...

Calculating the solar system size based on their utility bill would never be  correct ?

 

Thanks again, I'm glad to be on this forum :)

 

 

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9 hours ago, geert said:

I saw in some hybrid inverter manuals that they talk about the pf = 1.0, but I guess that is only the output pf?

Yes, it means that the rated power and rated VA both peak together at a power factor of 1.0 now; for earlier models that was PF0.8.

9 hours ago, geert said:

Calculating the solar system size based on their utility bill would never be  correct ?

It's not too bad. Utility bills are based on real power, and that's what you need to be able to supply from the battery and/or panels, with an allowance for losses. But you also need an allowance for the power factor and surge power of loads. Motors are especially bad: they have a power factor of about 0.8 when running, and they draw 5-7x their running power in their start-up surge. If your only load is say a largish pump motor, then you may need a much larger inverter and battery to be able to start it, unless you can somehow soft start it.

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