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Inverter Output Priority


CM21
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Hi all I recently upgraded my inverter to Voltronics off grid VMIII model and added a pylontech battery. I already have 6x 335watts panels connected in series to both charge the battery and power the loads. Grid is used as a last backup on days of bad weather. What i have noticed is that during the day, Inverter is drawing from batteries instead of solar panels. output priorty is set as SBU. I have tried to change to SUB but still the inverter prioritises utility to power loads even when Solar power is availale. Is there anyway of working around this?

Edited by CM21
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From your description I think it's likely that the inverter is not receiving enough solar to run the load, have you checked your load and solar input when you noticed this? Bear in mind that, yes, you might have 6*335W panels but the 335W figure is obtained under close to perfect conditions and not what you will see in the field. If in SBU and a cloud passes over the inverter will draw from battery so is it a constant problem? Likewise in SUB it will draw from utility. As you have a lithium battery minor cycling is not something I would be too worried about but obviously you don't want to leave the battery drained too much in case of outage. Are you monitoring your system with ICC or similar?

 

Edited by Shadders
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@Shadders
 I fully understand what you are saying. Bear in mind that my highest load is an electric water pump which consumes about 1.2kw which runs for approximately 1 hour tops and my day load is approximately 180 watts till 18hrs. Surprisingly I do achieve STC and exceed it every day when charging my battery while pumping water. But my worry is once I switch off the higher load from the pump inverter switches to power the 180watts load from battery. I think my panels have sufficient power to cover 180 watts. I have tried changing output priority settings on inverter but as I said solar is only prioritized when I connect higher wattage loads. Unfortunately I have not connected any ICC equipment yet. Just using Watchpower to monitor basic stats.

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Hmm, very puzzling. I've never noticed anything similar on my VMIII. You can log the values in watchpower, this may help check exactly what's what. Another option is to use an OTG cable and usb stick to pull off the logs but this isn't perfect because the logging time is limited to 10min unless in alarm or changing modes.

Have you set up the time based priority changes on the VMIII, maybe that's causing confusion?

The obvious way to force the panels to work at max is to turn off the AC supply but that leaves you open to a drained battery on cloudy days.

This might be a bug but it's not one I've ever come across before. Perhaps wiser heads will have better ideas.

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@Shadders
 So you are saying in your case your PV are able to power loads directly all day until Sun goes down? I have started logging data in Watchpower. Will see what I can analse tomorrow. Time based priority settings default to 0 after a while so they are not permanent. I do that just in case my battery runs out just before the sun comes out, I put it in SUB just for an hour and back to SBU for the rest of the day. Remember my load during the day is about 180watts minus the pump. So I am not looking to max the panels but have them produce=day load. When charging the battery and running water pump, I do see them max out. Unless maybe for the type of inverter I have PV can not by pass battery and has to rely on replacing energy lost from battery supplied to loads. I hope it's not a bug but I will wait to hear from others before I begin bothering the distributor. Dropping the AC breaker is the very last option I want to take, hoping the inverter can help me prioritize solar over battery power once battery is fully charged.

Edited by CM21
wrong spelling
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11 hours ago, CM21 said:

What i have noticed is that during the day, Inverter is drawing from batteries instead of solar panels.

Are you actually checking the battery discharge current, or are you just watching the arrows on the front panel? During the day, you want to be in battery mode, so the battery will potentially be discharged, but if you have enough solar power, it should only be for short periods of time and soon replaced by some solar power.

What is your main (U1) firmware version? I think that older versions had some problems with solar power management. This could be one of the actually fairly rare cases where a firmware update might fix the problem.

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8 hours ago, CM21 said:

 So you are saying in your case your PV are able to power loads directly all day until Sun goes down?

Yes it does provided solar power >= load. Arrows on the display can be misleading so do as Coloumb says. The logging should also help clear what is happening quickly.
 

8 hours ago, CM21 said:

So I am not looking to max the panels but have them produce=day load

Sorry, I misspoke regarding this. I meant that the inverter will always use panels (or battery) and not AC so they will be used to the full extent necessary. By turning off AC you will force the inverter to not use AC however the panels won't be running at 100% necessarily... the power draw from them will be equal to the load + any battery charging required.

 

I am running the latest firmware (91.02).One of the differences I have noticed is improved fan control so it's worth updating just for less noise imo 😁.

Edited by Shadders
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4 hours ago, Coulomb said:

Are you actually checking the battery discharge current, or are you just watching the arrows on the front panel? During the day, you want to be in battery mode, so the battery will potentially be discharged, but if you have enough solar power, it should only be for short periods of time and soon replaced by some solar power.

What is your main (U1) firmware version? I think that older versions had some problems with solar power management. This could be one of the actually fairly rare cases where a firmware update might fix the problem.

I am using the watchpower App on my phone. It says I m discharging 5amps from the battery. Firmware version says 41/15. Output priority setting is set to SBU.

Screenshot_20210403-095409_WatchPower.jpg

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2 hours ago, Shadders said:

Yes it does provided solar power >= load. Arrows on the display can be misleading so do as Coloumb says. The logging should also help clear what is happening quickly.
 

Sorry, I misspoke regarding this. I meant that the inverter will always use panels (or battery) and not AC so they will be used to the full extent necessary. By turning off AC you will force the inverter to not use AC however the panels won't be running at 100% necessarily... the power draw from them will be equal to the load + any battery charging required.

 

I am running the latest firmware (91.02).One of the differences I have noticed is improved fan control so it's worth updating just for less noise imo 😁.

How do u upgrade firmware? I suspect that could be one of the reasons my solar panels are not being prioritized over battery.

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1 hour ago, CM21 said:

How do u upgrade firmware?

I got my VMIII firmware files from here:

https://www.ostrovni-elektrarny.cz/support/Axpert/FW/

Unzip the file and follow the instructions in the pdf. Please make sure you you have the correct model Axpert and don't disturb the update once you start. The VMIII 91.20 file here was the one I used for my 5kva and it should be the same for the 3kva. 

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21 minutes ago, Shadders said:

Wow. At 9.54 I certainly would expect better generation from your panels than 50W unless it's cloudy or there's shading.

This is what happens when I run the pump, fully covered by PV. Then when switched off and load goes back to 160watts, battery is prioritized. I wonder why it's only reacting to bigger loads

Screenshot_20210403-120739_WatchPower.jpg

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4 hours ago, Coulomb said:

That doesn't seem all that old. Really old is 20.xx.

So I don't know if updating the firmware will fix it. Could be worth a try.

Unfortunately I changed the firmware to 20.59 and nothing has improved. Do u have any other firmware I can use.

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8 hours ago, Coulomb said:

Shadders (4 posts before yours) has the link to the latest firmware for VM IIIs, 90.20. He indicated that he's running it successfully.

I have tried downloading that one and it says app can't run on my PC. Any other alternative link I can try to download the same version

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2 hours ago, CM21 said:

I have tried downloading that one and it says app can't run on my PC

? Perhaps your computer doesn't know what application to use to handle .7z files?

I tried renaming it to .zip, and Windows explorer would not open it. So it looks like you have to download the free 7-zip Windows application: https://www.7-zip.org/download.html . It's free, painless to use and install, and useful.

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3 hours ago, Shadders said:

I use 7zip and it's brilliant freeware. I can convert the file to .zip and upload here if you run into further trouble with it.

Thanks i managed to unzip and run the software but the Inverter wont just accept the firmware upgrade. It keeps giving me an EEPROM error, whatever that means. By the way any idea where i can download a free trial for the ICC software? Will use one of my computers as a logger for the data. @Coulomb Your expertise may be needed here. I hear you are legend in these streets.

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7 hours ago, CM21 said:

the Inverter wont just accept the firmware upgrade. It keeps giving me an EEPROM error,

Are you saying that the update process fails, i.e. this error message comes from the reflash tool, or you have flashed the new firmware to the inverter, and now the inverter has an EEPROM error?

I don't see the string "eeprom" in the UPSReflashTool.exe executable (it could of course be hidden).

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8 hours ago, CM21 said:

Thanks i managed to unzip and run the software but the Inverter wont just accept the firmware upgrade. It keeps giving me an EEPROM error, whatever that means. By the way any idea where i can download a free trial for the ICC software? Will use one of my computers as a logger for the data. @Coulomb Your expertise may be needed here. I hear you are legend in these streets.

ICC runs on a Raspberry pi and sadly they don't offer trial versions anymore. Solpiplog is another pi monitoring software that's free. You can find it on github and it does pretty much the same as ICC but doesn't seem to be as up-to-date or well supported. If you are wanting to use a pc to log watchpower is okay (but not great) and free. Someone on the forum recently posted his software for which he was looking for beta testers.

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3 hours ago, Coulomb said:

Are you saying that the update process fails, i.e. this error message comes from the reflash tool, or you have flashed the new firmware to the inverter, and now the inverter has an EEPROM error?

I don't see the string "eeprom" in the UPSReflashTool.exe executable (it could of course be hidden).

The flashing tool reports successful but the inverter gives an EEPROM error and when I check the firmware version it still remains the same as before.

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2 hours ago, Shadders said:

ICC runs on a Raspberry pi and sadly they don't offer trial versions anymore. Solpiplog is another pi monitoring software that's free. You can find it on github and it does pretty much the same as ICC but doesn't seem to be as up-to-date or well supported. If you are wanting to use a pc to log watchpower is okay (but not great) and free. Someone on the forum recently posted his software for which he was looking for beta testers.

I meant logging data on my computer using Raspberry PI without the hardware. I just buy the software. I am already logging Watchpower and it's not effective in giving me real SoC for the battery. I really need something that will do that and help me prioritize solar during the day. I will check out solpiplog and see how it works. I am trying to avoid buying full kit because it's pricy. I don't mind buying the software alone and using my computer as a logging device for Raspberry PI.

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15 hours ago, CM21 said:

I meant logging data on my computer using Raspberry PI without the hardware. I just buy the software. I am already logging Watchpower and it's not effective in giving me real SoC for the battery. I really need something that will do that and help me prioritize solar during the day. I will check out solpiplog and see how it works. I am trying to avoid buying full kit because it's pricy. I don't mind buying the software alone and using my computer as a logging device for Raspberry PI.

If you have a battery comms cable from the Pi to the battery, then you can switch inverter mode based on the true SoC with software such as ICC or solar assistant. This page explains how it works: https://solar-assistant.io/help/power-management/axpert

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Hi all! I am planning to add 9 x 455 watt solar panels to my VMIII and run it in SUB. The installer came to take measurements for panel fixtures. Looking at VMIII he said my AGM batteries will die soon even if using the SUB mode. Why would he say that? Is it true? I thought VMIII could mix solar and utility and work even without batteries...

Edited by Ros
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