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Axpert Max is feeding into the grid !


wtjaden
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Im running the Axpert Max and noticed that this inverter in line mode feeds power to the grid and this causes my prepaid meter to trip.
Looking through the configuration settings there's no mention of anything related to grid feedback.

it seems that when there's surplus energy from the solar panels  sometimes the Max charges the Pylon but most of the time it dumps surplus to the grid tripping my Meter.

This is while the battery is low and needs a charge...

So my only option currently is to run in SBU mode  because SUB mode is not currently what i thought it would be (carry loads with utility and solar  and if there's surplus solar charge the battery) the way the kIng works    the max randomly dumps power to the grid tripping my meter.

SBU is a problem because i only have one US3000C currently and do not want to put to much load on it when solar production is low and a kettle boils while a aircon runs for example.

 The Max is  new so there's not much info out there about this inverter  im hoping that eventually  this problem can be addressed with a firmware update.

Edited by wtjaden
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Its a different design to the KIng
the MPPT trackers are high volt 500v max  and seems to connect to the high volt dc but in the inverter not the low volt battery dc bus.

Got it from Diygeek.co.za
 

not much info available from anywhere 

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On 2020/11/18 at 2:12 AM, DaveP said:

I was always under the impression it was like the king but can take a bigger load.

As Wtjaden mentions, it seems to be a higher power version of the Axpert MKS II, with extra power and two MPPT trackers. However, the maximum battery charge current is limited to 80 A, meaning you can only charge your battery with around 4000 W. You could presumably power the loads with up to 7200 W, and charge the battery with what's left up to 8000 W.

It's also limited to 6 machines in parallel. Perhaps their test facility can't test more than 45 kW.

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15 hours ago, wtjaden said:

Its a different design to the KIng
the MPPT trackers are high volt 500v max  and seems to connect to the high volt dc but in the inverter not the low volt battery dc bus.

Got it from Diygeek.co.za
 

not much info available from anywhere 

Full Circle Solar seem to sell them (out of stock at the moment though). https://www.fullcirclesolar.co.za/product/7-2kva-7200kw-axpert-king-max-vat-incl/

Perhaps they can give you some feedback

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6 hours ago, DaveP said:

Full Circle Solar seem to sell them (out of stock at the moment though). https://www.fullcirclesolar.co.za/product/7-2kva-7200kw-axpert-king-max-vat-incl/

Heh. They have the word "king" in the URL for the MAX, but the word "king" doesn't appear on the web page. That possibly explains @DaveP's belief that it was related to the Axpert King.

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9 hours ago, DaveP said:

Full Circle Solar seem to sell them (out of stock at the moment though). https://www.fullcirclesolar.co.za/product/7-2kva-7200kw-axpert-king-max-vat-incl/

Perhaps they can give you some feedback

My inverter is actually branded Full Circle Solar.
ill ask them if they have some info about this feed into grid by a offgrid inverter . 🤨

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Ok so i flashed to latest firmware from https://www.ostrovni-elektrarny.cz/support/Axpert/FW/

 

MAX7200_Main_CNTL_DSP_90.11 and  MAX7200_RemotePanel_Reflash_MCU(12.03)
and since the update SUB (line mode) no longer feeds power into grid.

will monitor but seems that the issue was fixed with a firmware update 

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7 hours ago, wtjaden said:

Ok so i flashed to latest firmware from https://www.ostrovni-elektrarny.cz/support/Axpert/FW/

 

MAX7200_Main_CNTL_DSP_90.11 and  MAX7200_RemotePanel_Reflash_MCU(12.03)
and since the update SUB (line mode) no longer feeds power into grid.

will monitor but seems that the issue was fixed with a firmware update 

Interesting, could that you could potentially have a grid-tie type inverter depending on the firmware installed?

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It turn out that firmware version 90.11 disables SUB mode so the inverter then only have battery mode and utility mode :(

My inverter came with 45.02   and i just flashed 45.04  SUB mode working again and ill test with this firmware.
i would think that they can adjust the amount of utility power draw to prevent a cloud moving away from the sun to not send power back to grid 

Edited by wtjaden
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  • 3 weeks later...
On 2020/11/24 at 3:59 PM, wtjaden said:

It turn out that firmware version 90.11 disables SUB mode so the inverter then only have battery mode and utility mode :(

My inverter came with 45.02   and i just flashed 45.04  SUB mode working again and ill test with this firmware.
i would think that they can adjust the amount of utility power draw to prevent a cloud moving away from the sun to not send power back to grid 

New firmware 90.19 did not send power back to grid but no tested 

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7 minutes ago, DaveP said:

Good to hear.

What software are you using to monitor your system?

Software is called Solar Assistant and is almost out of Beta i believe ( i'm a beta tester with the Axpert Max 7.2)
must say it really works well and looks good with the web monitoring  and  grafana graphs  and android web app is awesome also.
SOC switching etc

@Solar Assistant is a member on the forum if your interested 

 

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Just now, wtjaden said:

Software is called Solar Assistant and is almost out of Beta i believe ( i'm a beta tester with the Axpert Max 7.2)
must say it really works well and looks good with the web monitoring  and  grafana graphs  and android web app is awesome also.
SOC switching etc

@Solar Assistant is a member on the forum if your interested 

 

Ok cool, how are you connected to the inverter?

Do you know if this could be used on the Axpert Kings?

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3 minutes ago, DaveP said:

Ok cool, how are you connected to the inverter?

USB  direct
also supports usb pylon console cables for battery temp and individual cell voltages 

Do you know if this could be used on the Axpert Kings?

  • InfiniSolar V1 & V2
  • Axpert King
  • Axpert Max 
  • Axpert VM
  • Axpert King in parallel (2 or more)
  • InfiniSolar Super in parallel (2 or more)
Edited by wtjaden
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On 2020/12/15 at 4:20 AM, wtjaden said:

Yes i updated last night and i can confirm i've not had any issues yet looks like 90.19 do not feed into grid in SUB mode.

 

 

I am about to buy 4 units of the PIP 8048 MAX inverters.

Do you think that this issue with feeding back to the grid is resolved in this model?

I will use it in SBU mode, only using the grid as a backup when the batteries gets too low.

Thanks

Jesper 

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12 hours ago, Jesper said:

I am about to buy 4 units of the PIP 8048 MAX inverters.

Do you think that this issue with feeding back to the grid is resolved in this model?

The 8000 W model seems to be a little different to the 7200 W model, and the latest MAX firmware (version 90.19) doesn't support 8000 W. So while I expect that they will have solved the problem at the factory, it may not be in units that are sitting on a shelf somewhere.

So you will need to get the latest firmware for the 8000 W models. MPPSolar are generally OK at providing firmware when genuinely needed, they can sometimes be slow at providing the needed firmware update file. So perhaps patience and/or caution are advised.

I don't know why there is a 7200 and an 8000 W model. 6500 W for the 120 V model is fair enough; there are limits to the current that can be carried by printed circuit board tracks.

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Thanks for your explanation. Hopefully this is resolved on the units I will receive.

A different between the 7200 and the 8000 model is not just the AC output but also the MPPT charger. It goes from 80A to 120A.

I have 30kw pv, so I am going to max out the inverters pv power input capacity. So I was thinking that the 8000 model is good for me to utilize my PV power to the charging of the battery bank.

 I am also considering to double up the battery capacity in a year of two, when I have made enough savings on our electricity bill.

There is something I don;t understand, maybe you can explain. The 7200 model has a max pv power input on 8kw, the same for 8000 model, but the inverter output is bigger and the charging is bigger on the 8000 model. Why is it that the rated pv power input are the same on the two? To my logic it should be bigger on the 8000 model.

Jesper

 

 

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14 hours ago, Jesper said:

Thanks for your explanation. Hopefully this is resolved on the units I will receive.

I suspect you'll be chasing firmware updates.

14 hours ago, Jesper said:

There is something I don't understand, maybe you can explain. The 7200 model has a max pv power input on 8kw, the same for 8000 model, but the inverter output is bigger and the charging is bigger on the 8000 model. Why is it that the rated pv power input are the same on the two? To my logic it should be bigger on the 8000 model.

So they both have dual ≈4000 W MPPT solar charge controllers. These are boost-only units that boost (or connect through) the PV panel voltage to the bus voltage. From there, that can be sent to the loads, though only 90% of that 8 kW can go to the loads on the 7.2 kW model. On that model, the last 800 W can't be used unless there is at least 800 W of battery charging (ignoring losses for simplicity).

The path from PV to battery goes through two additional bottlenecks: the DC-DC converter, and a buck stage. The DC-DC converter has to be capable of full power, so at least 150 A (7.2 kW model) or 167 A (8 kW model), either direction. However, the buck stage is asymmetric in its power capability. When not utility charging, it's "straight through", and dissipates relatively little power. When battery charging (PV or utility or both, in this model) is in progress however, it is usually called upon to buck the bus voltage down so that the battery doesn't get over-charged. For example, consider the panel voltage is 400 V, and the battery is at 50 V. So the bus is also at 400 V (it's already way higher than the ~340 V needed to generate a 230 V sine wave, and lower bus voltage means higher efficiency). The transformer turns ratio on 64 V models is 1:7, so the high voltage end of the DC-DC converter will be 50 x 7 = 350 V. So the buck converter has to be capable of bucking those 50 V at maximum battery charge current, which is 80 A (7.2 kW model), or 120 A (8 kW model). So the 8 kW model's buck converter will see 17 A while conducting and 15 A average. On all the Axpert models, the buck converter seems to be dimensioned handle less power towards the battery than away from the battery. Presumably, this reflects the lower likelihood of required battery charging current, versus required battery discharge current. This is even more apparent on the low voltage SCC models, where the buck converter is in operation only when utility charging, not PV charging. So only around 4 kW (7.2 kW model) or 6 kW (8 kW model) goes from the DC bus to the battery. Full rated power (7.2 or 8 kW) can go from the bus to the load. So the battery charging path is a relatively small part of the "power budget" for bus power (usually supplied only from PV). That, plus the cost savings of having the same pair of solar charge controllers in the two models, is presumably why the input power rating is the same for the two models.

Sorry for the drawn-out explanation. It was good for me to go through the exercise; I now realise that on these models, the buck converter pretty much exclusively sets the battery charging power.

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On 2020/11/22 at 7:53 PM, DaveP said:

Hi Gents

I have the same grid feed-in problem with a Max 7.2, also bought from Full Circle Solar. I downloaded firmware version 90.19 from the above site but I cannot get it uploaded to the inverter.

1715189504_Screenshot2020-12-22142412.jpg.42e83f340248514f0effbd3d5695d292.jpg

This is what I get on my screen. What am I doing wrong? 

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Hi Coulomb

Thanks for the info! That now make more sense on this type of inverters.

Have also picked up that if two 7.2's are used in parallel then the battery current is still limited to only 80 Amps. This means it is then limited to 40 amps only per inverter? Full current is however available for the load...

Not sure if this is normal? Maybe you can help?

Regards

Piet

 

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