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Hi Guys,

A few questions I hope one or more of you may be able to help me with.  I’m a newbie on a steep learning curve.  First my system comprises x10  second hand 355 Watt Canadian Solar panels feeding an Axpert VMii 5KW inverter.  The battery is a single Pylontech US2000 which I hope to add another three units to when I can afford it.  My questions are:

1.            Does anyone have the correct inverter battery settings (in USR mode) for this battery when used with this inverter?  I actually have some settings from Pylontech but I think they may be referring to the VMiii rather than VMii inverter.  Currently these settings keep telling me that the battery is at a low state of charge and setting off an alarm [04] whilst the battery LEDs indicate it is fully charged. I assume that the VMii is unable to use the Ethernet port to ‘talk’ to the battery unlike the VMiii.

2.            When drawing power from the grid, there appears to be a lower limit on current being taken.  In other words, if the inverter is supplying power to the load and the load is removed, the current drawn from the grid doesn’t drop below about 1.5 Amps despite the fact that the load is virtually zero.  I am aware that the inverter also takes power for its own purposes but surely not that much?  (A friend with the same inverter sees the same thing) Is it possible that this is a measurement error due to the type of load?  I measure the grid current by an AC ammeter in series with the live supply line and I also have a digital readout of voltage and current that uses a Current Transformer to sample the current drawn.  Both methods produce the same result.

3.            I have downloaded the very useful Axpert Settings 1.1 file by Chris Hobson.  This has helped a lot with deciding which settings to use but I am a little confused by the need to start the inverter on batteries as mentioned in the Addendum.  The inverter is designed to run without batteries when necessary so why is this a requirement?

4            Are there any other useful guides to understanding the VMii settings out there?  Either textual or YouTube.

Many thanks for your time,

Trev

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16 hours ago, Trev501 said:

1.            Does anyone have the correct inverter battery settings (in USR mode) for this battery when used with this inverter?  I actually have some settings from Pylontech but I think they may be referring to the VMiii rather than VMii inverter. 

The inverter model doesn't matter as far as the battery settings are concerned (assuming battery type is USE). There are several sets floating around; these are the ones I recommend:

203529550_PylonTechsettings.png.f5579d2c24ef284ea613fa8ce9a060b4.png

16 hours ago, Trev501 said:

I assume that the VMii is unable to use the Ethernet port to ‘talk’ to the battery unlike the VMiii.

Correct.

16 hours ago, Trev501 said:

2.            When drawing power from the grid, there appears to be a lower limit on current being taken.  In other words, if the inverter is supplying power to the load and the load is removed, the current drawn from the grid doesn’t drop below about 1.5 Amps despite the fact that the load is virtually zero.

There is a largish capacitor across the AC input, and this (or something else) causes significant imaginary power to be drawn by the inverter. This does no harm, and you only get charged for real power (which is a small fraction of that), so just ignore it. Voltage times current gives you apparent power, which in this case is close to the imaginary power. The capacitance will actually slightly correct your house's power factor (which is almost always inductive).

16 hours ago, Trev501 said:

3.            I have downloaded the very useful Axpert Settings 1.1 file by Chris Hobson.  This has helped a lot with deciding which settings to use but I am a little confused by the need to start the inverter on batteries as mentioned in the Addendum.  The inverter is designed to run without batteries when necessary so why is this a requirement?

Chris' settings file was written a long time ago, before batteryless operation was possible.

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Sory, I forgot to add a couple of supplementary questions.  I notice the fans on my VMii inverter are on permanently regardless of load, is this correct?  Also, when I eventually add to my Pylontech battery, as the ethernet cable to the inverter is not in use, does this mean that the interconnecting ethernet cables are also not needed or do the batteries communicate with each other?  Thanks again

 

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1 hour ago, Trev501 said:

notice the fans on my VMii inverter are on permanently regardless of load, is this correct?

The VM models have weird fan control. It looks to me that only one fan may be PWM controlled; the other may be on/off. This seems to be one of the cost cutting areas for the "V" (Value?) models. It doesn't seem to me to be a good place to cut costs. Others have mentioned that the VM models are noisy.

Quote

Also, when I eventually add to my Pylontech battery, as the ethernet cable to the inverter is not in use, does this mean that the interconnecting ethernet cables are also not needed or do the batteries communicate with each other?

You won't need the cable between the inverter-charger and the battery. But when you add the second battery module, you'll still have to use the short RJ-45 (or is it RJ-11?) cable(s) between modules; that's how the BMS on each module talks to the others.

Edited by Coulomb
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You will probably benefit from adding the Centurion Solar Rasberry Pi monitoring to your setup - it allows for the Pylontech to talk to the Axpert inverters .

Also make sure that when you are running off grid without solar that your load dont exceed the 1.3kW rating of the Pylontech US2000. 

 

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