Hi All

I've been running with my RCT 8KW MAX unit for a few months with no issues at all, but now that I've decided to make use of the 2nd MPPT I've had some issues.

My setup:

RCT MAX 8KW Axpert Inverter

4x Deltec 100AH AGM Batteries

6x 435w JA Solar Panels connected in series on MPPT 1

4x 540w JA Solar Panels connected in series on MPPT 2

Now the problem I'm having is the inverter starts acting strange once it exceeds or matches the continues load of around 3000w. Once the solar can easily manage the load (around 12:00-14:00) it suddenly starts switching back and forth between SBU and SUB (It actually cuts off the Grid completely and connect again in a few seconds there after. So it continues until the solar peak is over) for no reasons at all. I've tried messing with different settings and also tried to keep it on SBU and other times also on USB, but with no joy.

No matter what I try and do, the inverter does not want to run stable once the wattage reaches or exceeds about 3000w.

I was maybe thinking that the 2x MPPT should be matched up with the same specs voltages etc, but then again, it states it's 2x individual MPPTs and should easily be able to run like this in my understanding?

Another thought that crossed my mind was that the rated 450v could be for the the combined MPPTs and not 450x2, but I've now tried putting the 1st set of panels into 2x strings of 3xpanels to reduce the voltage, but it does exactly the same as well.

Maybe buggy firmware or worst case scenario, a faulty unit perhaps?

I really enjoyed the inverter before, but now I'm a bit disappointed that I cannot make use of the 2x MPPTs as that was the main reason why I've upgraded to this unit in the first place.

Any advise from you guys would be greatly appreciated.

Thank you

1 hour ago, The_Duk3_ said:

it suddenly starts switching back and forth between SBU and SUB

Do you mean it switches between battery mode (battery and solar powering loads) and line mode (line, battery, and solar powering loads)? Or do you actually see SBU and SUB on your monitoring software?

1 hour ago, The_Duk3_ said:

Maybe buggy firmware or worst case scenario, a faulty unit perhaps?

Buggy firmware is a possibility. What is your main (U1) firmware version?

A faulty unit is possible, but seems much less likely.

30 minutes ago, Coulomb said:

Do you mean it switches between battery mode (battery and solar powering loads) and line mode (line, battery, and solar powering loads)? Or do you actually see SBU and SUB on your monitoring software?

It actually just switches without changing the source priority of the software. Example: if I leave it in USB mode it will at some point start dropping the grid completely and then powering the loads with Solar and Battery, but also carrying the load for only 5 seconds and then connecting the grid again and then repeat the cycle over again. (At the time of switching the batteries and solar power is more than capable of carrying the load as well and I've also tried lowering the back to grid voltage to 46v just to check if it's not the battery voltage that's causing the issue)

SBU and SUB Modes will do exactly the same as USB. It's almost like you are continuously disconnecting the unit from the grid every 5 seconds.

 

37 minutes ago, Coulomb said:

Buggy firmware is a possibility. What is your main (U1) firmware version?

A faulty unit is possible, but seems much less likely.

Main CPU version: 00046.05

Secondary CPU version: 00012.06

Is there perhaps newer firmware that I can possibly try?

20 hours ago, The_Duk3_ said:

Main CPU version: 00046.05

Secondary CPU version: 00012.06

Is there perhaps newer firmware that I can possibly try?

Unfortunately, I don't know of any 46.xx firmware update files. However, I've just uploaded version 90.06, which is only a few weeks old. Being a 90.xx version, it may be experimental, though it seems from other posts that they are being treated as production firmware.

There is also removable display firmware version 12.11 somewhere, but that doesn't seem to be related to your issues. Use at your own risk.

12 minutes ago, Coulomb said:

There is also removable display firmware version 12.11 somewhere

Now here:

 

23 hours ago, The_Duk3_ said:

I really enjoyed the inverter before, but now I'm a bit disappointed that I cannot make use of the 2x MPPTs as that was the main reason why I've upgraded to this unit in the first place.

Any advise from you guys would be greatly appreciated.

Could it be a battery issue? Just 100Ah on an 8kW inverter seams to me rather low in addition to being AGM. Perhaps with the 2 MPPT under full sun the battery goes into overvoltage.

And make sure the PV array connection voltage is in line with the MPPT specifications. The PV OCV to be within the MPPT operation voltage.

1 hour ago, Coulomb said:

Unfortunately, I don't know of any 46.xx firmware update files. However, I've just uploaded version 90.06, which is only a few weeks old. Being a 90.xx version, it may be experimental, though it seems from other posts that they are being treated as production firmware.

Thank you so much Coulomb. I appreciate your assistance. I will test the unit over the weekend maybe with grid manually disconnected and see what the unit will do when there is no grid attached. I will need to be brave and try the newer firmware as well and see if it might solve my issue.

1 hour ago, Beat said:

Could it be a battery issue? Just 100Ah on an 8kW inverter seams to me rather low in addition to being AGM. Perhaps with the 2 MPPT under full sun the battery goes into overvoltage.

And make sure the PV array connection voltage is in line with the MPPT specifications. The PV OCV to be within the MPPT operation voltage.

Thank you for the advise Beat. My batteries are mostly just connected for power outages/load shedding with less load running at the time. In terms of charging, the Amps is limited to 20amps max charging which is under the 30A rated per battery.

The PV voltages are also well under the rated 450v by the MAX inverter as well.

On 2022/03/24 at 3:27 PM, The_Duk3_ said:

In terms of charging, the Amps is limited to 20amps max charging which is under the 30A rated per battery.

I don't know the concept of your inverter with 2 MPPTs. Make sure that the current limits are applied per MPPT or for the sum of the two.

In my system with 2 inverters hence 2 MPPTs I must set the current limits in each unit at half the total value aimed.

@Coulomb thank for the updates on the firmware. I just upgraded to a Mecer Sol-I-AX-8M inverter and its running Main CPU 72.01 and Remote ppanel 12.13, i emailed supplier and mustek for firmware updates as this inverter is doing funny thing like never charging the battery they send me Main firmware 46.05 and Remote firmware 12.13. My question is watt do i use. The Mustek firmware 46.05 or the firmware on the net 90.06 and why is my inverter running 72.01??? Im very confused and dont want to brick my inverter. Already sold my older inverter that i also had to upgrade the firmware to work correctly. But now i am scared to use the wrong one.

I read through most of the forum and found most people have the 46firmware and havent found anyone with 72.01 firmware. The box was opened when i got it but i thought maybe they just updated the firmware thats why it was opened but now i am worried someone send the unit back after they loaded the wrong firmware.

Any advise would be greatly appreciated.

Edited April 8, 20224 yr by Henry2501

10 hours ago, Henry2501 said:

My question is watt do i use. The Mustek firmware 46.05 or the firmware on the net 90.06 and why is my inverter running 72.01???

Voltronic firmware numbering is quite confusing. I vaguely recall one of the models (perhaps a 7.2 kW MAX) having three different major version numbers (the number before the dot). My guess is that your machine might have been one of the first batch of 8.0 kW MAXs made, and they changed their minds about the numbering soon after. 72.XX is a particularly "overloaded" series: it could refer to PF0.8 MKS units from around 2016 (e.g. 72.40/60/70), to modern PF1 MKS models with 64 V max (e.g. 72.20), to Axpert Kings (overflowed from 71.xx), and I believe that the Axpert MKS IIs have overflowed from 71.xx to 72.xx as well.

My guess is that these other 72.xx firmwares would totally not work in an Axpert MAX, or at best would show a rated power (in WatchPower etc) of less then 8.0 kW.

I think it's safe to try to load 46.05. In the highly unlikely worst case that it bricks, it's their problem to fix (though highly inconvenient to you). But 46.05 is what should be in there, so it should work.

10 hours ago, Henry2501 said:

now i am worried someone send the unit back after they loaded the wrong firmware.

I think it's unlikely that this happened. I can't think of a reason for the box to be opened, unless they had it on display or some such.

Hello Coulomb

Thank you for your great assistance like always. I tried everything in the end and nothing worked. Took the unit in to my local mustek dealer and they replaced the main controller board as no firmware wanted to load on to it.T^hey even tried many times. new board now running 46.05

It seems to be behaving normally now but i only installed it today so will see.

Thank you again i just wanted to respond to you.

22 hours ago, Henry2501 said:

they replaced the main controller board as no firmware wanted to load on to it. They even tried many times.

Heh. Looks like that 72.01 firmware might have been an aberration after all.

Thanks for the update.

word of Warning to people with a Mustek Max 8kw inverter the one with the rgb led in front the straight RGB light not the round one. I have one of these Mustek inverters and it has been in twice to replace the Main controller. Eventually i asked for a new inverter and they did give me a new one as the old one is now only 5 months old.

 

WORD OF WARNING IF YOU HAVE A M3C3R MAX INVERTER

Dont load the new firmware on it as after exactly 60days mine said F90 error. MIGHT HAVE BEEN JUST MY BAD LUCK I DONT KNOW.  The firmware was loaded on the 12/4/2022 and on Sunday the 12/06/2022 F90 message appeared and nothing wanted to respond or work and no power to the house. I now have a new inverter but to scared to change the firmware to the new firmware as this one came with the same as my previous inverter fans are always on and very noisy. I just installed the new inverter again and will see if this firmware works correctly as the previous one did not charge the battery correctly. So time will tel. @Coulomb if i am wrong please correct me but now i feel like must3k might be importing Voltronic ripoff units or am i just being paranoid now. I remember reading somewhere on the forum about the F90 error.

THIS inverter has been nothing but a nightmare.

Driver

Axpert Max

Firmware version

72.01

Model number

44

Machine type

Off Grid

Topology

Transformerless

Max parallel units

9 units

Nominal battery voltage

48.0 V

Expected AC input voltage

230.0 V

Max AC input current

34.7 A

Max AC output current

34.7 A

Max AC output power

8000 W

Max AC output apparent power

8000 VA

1 hour ago, Henry2501 said:

if i am wrong please correct me but now i feel like must3k might be importing Voltronic ripoff units or am i just being paranoid now.

It's possible, but IMHO unlikely.

Fault code 90 coming up on proper (non-clone) Voltronic models is rare but unfortunately not unheard of. The code that triggers it is very complex, so it's easy to get it wrong.

Edit: @Henry2501, which firmware was the one that caused the fault code 90? Was it 72.01, or something else?

Intriguing that 72.01 says it's 8000 W. That means it's not one of the other 4 firmwares that have major version number 72.

Edited June 20, 20224 yr by Coulomb

2 hours ago, Coulomb said:

which firmware was the one that caused the fault code 90? Was it 72.01, or something else?

Hello @Coulomb I loaded the firmware from the forum the 90.06 under the download link

and exactly 60 days later F90 error. Already the New inverter stopped feeding Solar in to the house, had to restart 5 times then all of a sudden its feeding solar in to the house again. These Mecer units are nothing but problems as far as a i can see. This is is doing the exact same as the previous unit with the 72.01 firmware. Stop charging the battery and stops feeding power in to the house. When i loaded the 90.06 she was a bit more stable but still did it, but now i am scared.

Here you can see the inverter drops the solar for no reason then i have to restart constantly till she works again. I ran my old inverter my 5kv one for the last week and it never did any of this stuff just worked out the box. I got it back from the person i sold it to as he did not pay me. This happens at random and Mustek keeps telling me its not the inverter.

I dont know what to do anymore. as i paid R22000 for this thing.

 

Please see the images attached. you can see the solar just drops the 04/06/2022 is a perfect example of how the solar drops then pumps then drops then its like in perfect frequency. The guy at mustek sayd but than can just be clouds. Perfectly timed clouds must be.

 

Edited June 20, 20224 yr by Henry2501

So i got on the roof today and removed the Earthing cable from the Solar panels because the book implies no earthing of the solar panels. I have MONO panels so does not apply to that maybe there is a grounding earth leak somewhere. But i will monitor it.

21 hours ago, Henry2501 said:

I loaded the firmware from the forum the 90.06 under the download link

https://powerforum.co.za/files/file/82-axpert-max-8kw-main-firmware-version-90067z/

and exactly 60 days later F90 error. Already the New inverter stopped feeding Solar in to the house, had to restart 5 times then all of a sudden its feeding solar in to the house again.

Hmmm. As far as I can tell, this fault code 90 has nothing to do with the firmware, and your EEPROM might be incorrectly programmed. Or given that your inverter started working again after 5 restarts, maybe your EEPROM is intermittent or the flash "strength" is weak, so that it sometimes reads the wrong value. You have to read about a dozen locations perfectly correctly to avoid fault code 90 after 60 days.

If this is a manufacturing fault, then perhaps a lot of users will find themselves getting this fault code soon. That could be a nightmare to fix, since the official fix is to write a custom serial number programmer for each individual customer.

So you have the inverter working at present? With 90.06?

What happened to the machine with 72.01?

What firmware did 90.06 replace?

1 hour ago, Coulomb said:

So you have the inverter working at present? With 90.06?

Hello @Coulomb no this is a brand new inverter ( exact same model) with the original 72.01 firmware, but now the battery doesn't charge again. Thats why i upgraded the previous inverter firmware with the new firmware of 90.06 but then it failed after 60 days F90 error. ( Should i upgrade again DO you think)

So This Inverter is brand new - Original Firmware as from Mustek (Mecer) does not charge the battery unless you put it in grid only mode. then solar will charge the battery but then it wont feed the extra solar in to the house. Then you have to set it to SUB mode then it will feed power to the house but battery wont get charged. Also does the lose solar for no reason what i now call a bug. Yesterday on the new inverter i had to restart 5 times before the solar started working again. The exact same issue as the old inverter did in the beginning.

Battery is also set to only charge of the Solar.

On 2022/06/22 at 12:43 AM, Henry2501 said:

Should i upgrade again DO you think

I think first you should issue a QBOOT command (CRC bytes 0A and 88 hex). If you get "(1" response, all is good, there won't be a fault code 90 in 60 days.

If the result is "(0", then you will get the fault code in 60 days anyway.

If you do update to 90.xx, this will at least tell you if you need to find a different firmware that won't return "(0".

I hope I haven't just helped the clone makers. But I suspect that they know about this command already anyway.

But the fact that a brand new inverter came with 72.01 suggests that it's more recent than 90.06, which is now 4 months old (February 2022). What is the manufacturing date of your new inverter? [ Edit: if it's the one in the photo, that's January 2022, older than 90.06. Plus, you said that 90.06 seemed to perform better than 72.01. ]

Edited June 22, 20224 yr by Coulomb

On 2022/03/23 at 1:47 PM, The_Duk3_ said:

Hi All

I've been running with my RCT 8KW MAX unit for a few months with no issues at all, but now that I've decided to make use of the 2nd MPPT I've had some issues.

My setup:

RCT MAX 8KW Axpert Inverter

4x Deltec 100AH AGM Batteries

6x 435w JA Solar Panels connected in series on MPPT 1

4x 540w JA Solar Panels connected in series on MPPT 2

Now the problem I'm having is the inverter starts acting strange once it exceeds or matches the continues load of around 3000w. Once the solar can easily manage the load (around 12:00-14:00) it suddenly starts switching back and forth between SBU and SUB (It actually cuts off the Grid completely and connect again in a few seconds there after. So it continues until the solar peak is over) for no reasons at all. I've tried messing with different settings and also tried to keep it on SBU and other times also on USB, but with no joy.

No matter what I try and do, the inverter does not want to run stable once the wattage reaches or exceeds about 3000w.

I was maybe thinking that the 2x MPPT should be matched up with the same specs voltages etc, but then again, it states it's 2x individual MPPTs and should easily be able to run like this in my understanding?

Another thought that crossed my mind was that the rated 450v could be for the the combined MPPTs and not 450x2, but I've now tried putting the 1st set of panels into 2x strings of 3xpanels to reduce the voltage, but it does exactly the same as well.

Maybe buggy firmware or worst case scenario, a faulty unit perhaps?

I really enjoyed the inverter before, but now I'm a bit disappointed that I cannot make use of the 2x MPPTs as that was the main reason why I've upgraded to this unit in the first place.

Any advise from you guys would be greatly appreciated.

Thank you

Just a quick update...

I've ended up buying the RCT MAX2 unit, hoping that it will resolve my problem. Unfortunately the new MAX2 unit is having the exact same behavior than the MAX unit. I haven't tried updating any firmware as yet and honestly I did not want to risk bricking the units.

I'm now starting to believe something else is wrong with my setup or maybe it's possible that the reason is because of my mismatched panels?

I will continue using it like this and start saving again to eventually try and upgrade my PV panels to be identical panels as per what the manual recommends.

Thank you to all so far who provided their inputs and advise.

 

This is a wild gamble, but I have read your post and have a theory, these inverters, well the older ones like mine have a bypass enable and disable setting, it somehow decides that when drawing too much current from the batteries, to protect it it bypasses, my theory is that this is what is causing yours to do this, and this setting is based on your charging current to the batteries, so I think if you were to set this to a high value it might not do this. But then you risk the battery. 

The guys who know the firmware might know how these calculations are done.

Hi All

Where can i get a copy of firmware ver 46.05 for SOL-I-AX-8M?

Thanks

13 hours ago, Shamiel.sa said:

Where can i get a copy of firmware ver 46.05 for SOL-I-AX-8M?

The closest available at present might be 90.06. Why do you want this specific firmware version?

 

Hi Coulomb 

I have 3 of these units operational 

The one i seem to have a glitch with FW 46.04, the mixing/blending of Solar and utility.

The FW 46.05 seems to be stable in the same type of scenario.

90.06 will do the trick?

 

Thanks