INTRO:

Long ago i had the theory that Internal Supply of the inverter will cause currents on both mppts inputs which will interference with mppt regulation.

 

NOW IT'S PROVEN:

The simple solution is to pull of the plug on the supply pcb which is marked with "SOLAR".

The downside:   1. Loosing of Batteryless Operation .

                            2. Inverter will not start from PV inputs when its switched off by the button to charge the battery.

MPPT works now with a minimum current of 0.0002A    really   0.2mA   (first time i cant believe the measurement)

 

FIRMWARE Modification is still needed but just only a littlebit .....not so much as in the past.

 

@Coulomb

Only the subtraction value needs to be zero, no longer need to set the minimum MPPT voltage higher than 90V or reset mppt code.
Maybe we can even lower this for maximum compatibility.(eg 60v like in the twin models)

 

 

 

Here a picture of the disconnected plug (on the upper right)

The safest way is to completely disconnect your inverter from any powersource before pull of the plug .

 

RESULT :

 

I supply PV 2 input with a isolation tester which provide 250V

MPPT point found by the firmware at 168V and 0,000487A 

 

WOW this is 0,082 watts 😅

 

MAYBE IT CAN USE THE MOONLIGHT FOR SOLAR PRODUCTION??? I'll check

 

And we that updated with your patched firmware and dont have the 90v issue any more what to do ? Take out that con ecter or not?

10 hours ago, Georg594 said:

MPPT point found by the firmware at 168V and 0,000487A 

WOW this is 0,082 watts 😅

MAYBE IT CAN USE THE MOONLIGHT FOR SOLAR PRODUCTION??? I'll check

Heh. The measurement is in hundredths of an amp (10 mA units), and the tracker stops as soon as it finds an increase in PV power. So it just happened to stop at 168 V when it the first bit of noise caused the measured power to increase from zero to just over zero. The half milliamp of current draw that you measured is likely due to the voltage measurement resistors, not the boost controller actually pushing power to the DC bus.

This is however a great find. Perhaps they can fix it in future by moving where the current measurement is done. Maybe DIYers could even do the mod ourselves, and leave that connector in place.

[ Edit: On further thought, it may be that the power, which is in the form of spikey square waves, is inducing noise into the current measurement. (I'm guessing that this connector supplies HFPWR, high frequency power, from the main power supply). The fix might be as simple as adding a capacitor somewhere. ]

So with original firmware, it still gets stuck at 90 V even with the plug out? And the subtract zero completely fixes the problem, as long as the plug is removed?

Well done doing what Voltronic's engineers haven't been able to do for many years! 👍

Edited December 10, 20223 yr by Coulomb

 

Start today on a cloudy / foggy day

 

 

 

 

@Coulomb

your theory about the input resistance of the voltage measurement is way off reality 😀 .

Dont get me wrong but,

if we calculate the input resitance  168v & 0,00065A = 260 KOhm

this input resistor would create around 1 Watt of heat with a pv input of 500V,
and that makes no sence.

 

 

 

The firmware will calculate in 10mA steps right ,

but its so much tolerance in the measurement when current is below 0,1A that the inverter shows until 21W of PV input power (its way way of)

(my axpert & EASUN made the same wrong measurements)

......real was at that time 0,14W. (Here will become another firmware bug activ >>>begins to load battery from grid with 2 amps if grid is available).

advantage of this misbehavior >> Firmware starts mppt algorythm😆

 

The voltage of the PV input also changes in steps which would make sence that MPPT is already working.

so i made another measurement on the inverter with isolation tester as supply for the pv input 2   .

this time the current measuremt is in the wire between mppt pcb and main pcb .

it looks like that the Algorithm searches and find the mppt point

(positive value is current flow into DC Bus (still milliamps))

just look 😊

 

 

 

55 minutes ago, Georg594 said:

Your theory about the input resistance of the voltage measurement is way off reality 😀 .

...

This input resistor would create around 1 Watt of heat with a PV input of 500V, and that makes no sense.

Yes, of course 🤭 I didn't do any calculations. That current must be the current drawn by the logic, when it's not switching.

58 minutes ago, Georg594 said:

so i made another measurement on the inverter with isolation tester as supply for the pv input 2   .

this time the current measurement is in the wire between mppt pcb and main pcb .

Those currents seem too small to me to run the gate drivers. So I don't think it's attempting to find the maximum power point of your power supply.

So do you recommend that readers use your fully patched firmware with this, presumably the one with the lowest minimum MPPT voltage (I forget what that value was)?

Or will you come up with a minimally patched version?

Or would you prefer that I did that?

PV1 side west (only 4 trina 400w in series)

I think this is what we all want to see😋

 

 

Gate drivers supply & Logic are independent of the power input of the pv inputs.

 

But also i had to correct myself of the Firmware changes :

Two changes are minimum to get it work,the subtraction value set to zero  &  the compare with 0,5A (value 50) set to 1 .

 

I made an BETA Firmware based on 90.06 with just this two changes (named to 9007).

(MPPT RANGE IS ORIGINAL 90-450V )

testet on EASUN & Axpert Max I 8KW

 

@Coulomb

i would be happy if you patch other files if there is a request .

Reflash.zip

With this firmware we need to disconnect that connector or only flash it ?

Whats the difference between this firmware and the last one, 92.05 and 90.06 that georg patched? Thanks

5 hours ago, Georg594 said:

Gate drivers supply & Logic are independent of the power input of the pv inputs.

Where does it get power from then? From the DC bus perhaps? 

 

I disassembled my inverter today and did some measurements.

Hope i got it right 😉.

 

 

 

for testing i disconnct all plugs from help supply pcb and everything worked fine .....this made me suspicious

then i made a few measurements:

 

if only battery is available as power source this complete pcb is useless & main supply draws 0,45A from battery.(with 230V output active but no load  it is 1,75A)

if Grid is available the help pcb will provide 60V to main supply , battery is not used in this condition for feeding the logic

if Solar is available Grid will be ignored but will also it provide 60V to main supply , battery is also not used in this condition for feeding the logic

if you just pull off the SOLAR plug on help supply pcb then power comes from grid(if available) for all the logic (49w measured)

(this could result in 50 watts being permanently drawn from the grid)

 

 

 

 

it seems if you had a big battery (i got 1250AH 😉) it could make sense to disable the help pcb ,

and in this condion the "bug" to load battery with 2 amps when solar input is weak and grid is available makes now sence to prevent battery diacharge.

(disadvantage is inverter starts only when button is pressend , if it runs already it stays on )

 

 

 

 

 

 

 

 

MPPT pcb

there is a 12 wire connection to dsp pcb

maybe this could be the folloing signals

TEMP Heatsink           
TEMP of Air
PV1 Voltage
PV2 Voltage
PV1 Current
PV2 Current
PWM signal MPPT 1
PWM signal MPPT 2
GND
+12V from main supply
-12V from main supply
??? named O/P on pcb

 

 

 

Boys, can u answer to me ? Is there any new improvements or new firmwares that work better for 8k ?

No, less improvement 😉, the Firmwares in my other firmware development thread are 100% compatible (my versions and the others Coulomb made )

 

If you got already a patched firmware on your device just pull off the plug solar and test it . 

Still Beta development.

3 minutes ago, Georg594 said:

Nu, mai puține îmbunătățiri 😉, firmware-urile din celălalt fir de dezvoltare a firmware-ului meu sunt 100% compatibile (versiunile mele și celelalte produse de Coulomb)

 

Dacă aveți deja un firmware corelat pe dispozitiv, scoateți ștecherul solar și testați-l. 

Încă în dezvoltare beta.

What will be better with the connecter out?

4 minutes ago, add1c7ed55 said:

Ce va fi mai bine cu conectorul scos?

I have your patched version yet, it works very good without 90v stuck. With this connecter out what will be better?

1 hour ago, add1c7ed55 said:

I have your patched version yet, it works very good without 90v stuck. With this connecter out what will be better?

Interesting. Maybe your inverter has a hardware fix that Georg's and others' don't have.

But it may also be that you will see further improvement with the connector out, but this only shows up under certain conditions (involving low available solar power). In particular, when the PV power is low and something forces high PV voltage, the hardware bug seems to cause the PV voltage setpoint to drift downwards towards 90 V or perhaps 120 V after a few minutes.

It's probably worth trying, IF you don't mind opening the case (this likely voids your warranty), AND you are aware of the high voltage hazards that can exist inside an inverter even several minutes after all power is turned off. People like Georg and I don't think twice about opening the case, but for others, it's not so clear cut.

1 hour ago, Coulomb said:

Interesant. Poate că invertorul tău are o soluție hardware pe care Georg și alții nu o au.

Dar se poate, de asemenea, să observați îmbunătățiri suplimentare cu conectorul scos, dar acest lucru apare doar în anumite condiții (care implică o putere solară disponibilă scăzută). În special, atunci când puterea fotovoltaică este scăzută și ceva forțează o tensiune fotovoltaică ridicată, eroarea hardware pare să determine ca valoarea de referință a tensiunii fotovoltaice să scadă în jos spre 90 V sau poate 120 V după câteva minute.

Probabil că merită încercat, DACĂ nu vă deranjează să deschideți carcasa (acest lucru probabil vă anulează garanția) ȘI sunteți conștient de pericolele de înaltă tensiune care pot exista în interiorul unui invertor chiar și la câteva minute după ce toată puterea este oprită. Oameni ca eu și Georg nu mă gândesc de două ori să deschidă cazul, dar pentru alții, nu este atât de clar

It is opened yet. I turned the fans. I will try. Which will be the negative facts ? Wont be use as a charger and wont turn on only with pressing the button? Other negatives ?

I just want to know if I understand well If I unplug this cable....

if battery is suddenly disconnect but grid available, is the inverter continue to perform or it will shutdown ?

And if grid will be Always used to power Logic so what if grid suddenly become unavailable ?

On 2022/12/11 at 4:28 PM, Coulomb said:

Interesting. Maybe your inverter has a hardware fix that Georg's and others' don't have.

But it may also be that you will see further improvement with the connector out, but this only shows up under certain conditions (involving low available solar power). In particular, when the PV power is low and something forces high PV voltage, the hardware bug seems to cause the PV voltage setpoint to drift downwards towards 90 V or perhaps 120 V after a few minutes.

It's probably worth trying, IF you don't mind opening the case (this likely voids your warranty), AND you are aware of the high voltage hazards that can exist inside an inverter even several minutes after all power is turned off. People like Georg and I don't think twice about opening the case, but for others, it's not so clear cut.

Hi all. Today i disconnected the connector, here is cloudy and i hace 8kw pv installed, production with the cable connected is 250wh, with the cable disconected is 340wh. Tested 3 times. The question is, the inverter can work without this cable long time? Wont deffect Something in it in time?

On 2022/12/11 at 1:33 PM, Georg594 said:

 

I disassembled my inverter today and did some measurements.

Hope i got it right 😉.

 

 

 

for testing i disconnct all plugs from help supply pcb and everything worked fine .....this made me suspicious

then i made a few measurements:

 

if only battery is available as power source this complete pcb is useless & main supply draws 0,45A from battery.(with 230V output active but no load  it is 1,75A)

if Grid is available the help pcb will provide 60V to main supply , battery is not used in this condition for feeding the logic

if Solar is available Grid will be ignored but will also it provide 60V to main supply , battery is also not used in this condition for feeding the logic

if you just pull off the SOLAR plug on help supply pcb then power comes from grid(if available) for all the logic (49w measured)

(this could result in 50 watts being permanently drawn from the grid)

 

 

 

 

it seems if you had a big battery (i got 1250AH 😉) it could make sense to disable the help pcb ,

and in this condion the "bug" to load battery with 2 amps when solar input is weak and grid is available makes now sence to prevent battery diacharge.

(disadvantage is inverter starts only when button is pressend , if it runs already it stays on )

 

 

 

 

 

 

 

 

MPPT pcb

there is a 12 wire connection to dsp pcb

maybe this could be the folloing signals

TEMP Heatsink           
TEMP of Air
PV1 Voltage
PV2 Voltage
PV1 Current
PV2 Current
PWM signal MPPT 1
PWM signal MPPT 2
GND
+12V from main supply
-12V from main supply
??? named O/P on pcb

 

 

 

The second power supply unit (SPS) has only two inputs: battery and solar. I think it is not supplied by the grid (see also AXPERT MAX II 8KW service manual 20210730.pdf).

I was wrong! Grid is the input!

AXPERT MAX II 8KW service manual 20210730.pdf

Edited January 4, 20233 yr by Volker

2 hours ago, Volker said:

I think it is not supplied by the grid (see also AXPERT MAX II 8KW service manual 20210730.pdf).

I have to disagree:

At the right seems to be CN1 (can't see that above, but it lines up per the inter-board diagram at the end), and you can just barely read (AC/L) above, and (AC/N) below. I'm pretty sure that there is a clearer diagram somewhere, but it's getting late here again.

3 hours ago, Coulomb said:

I have to disagree:

At the right seems to be CN1 (can't see that above, but it lines up per the inter-board diagram at the end), and you can just barely read (AC/L) above, and (AC/N) below. I'm pretty sure that there is a clearer diagram somewhere, but it's getting late here again.

Ok, you saw it right. I had not opened the inverters until now.

I have now disconnected SOLAR from one inverter. Let's see how the PVs behave tomorrow....

When the SOLAR cable is disconnected at the SPS, EVERYTHING changes! No more morning gap.

https://powerforum.co.za/topic/15092-axpert-max-ii-10kw/?do=findComment&comment=145987

I got mine completely disabled and pulled of both plugs ( ac and solar)

 

Works best , minimized consumption from ac and nice mppt regulation, but beware if you got a small battery , in mode SUB mine isnt charging the battery when load is greater than pv input power.....in this state it draws around 1.5A from the battery.

I will also disconnect the cable to see how it behaves without it. What would be the disadvantages with a disconnected cable "SOLAR"? I use all 3 sources of energy from solar/grid/battery, not necessarily in that order....when there is enough sun, I often turn off the grid remotely through a contactor commanded by Shelly EM and stay on the battery...I wouldn't wants to stay without electricity in the house .. 

I only charge the baterry with solar "OSO" never on the grid!

From what I see from the graph you posted, there is a huge difference compared to the production with the cable removed and those without the cable removed This is basically how it should behave in low lights!

@Georg594 , i have also disconected the cable, suprizingly the production curve looked very nice, but suprisingly the information was wrong, meaning that with the cable out solar assistant showed me i have produced 10kwh, but actually in the battery went only 8kwh, you can investigate further but in my opinion if you take out the plug the information is wrong, and actually the real production is the same. 

5 hours ago, BGD said:

@Georg594 , i have also disconected the cable, suprizingly the production curve looked very nice, but suprisingly the information was wrong, meaning that with the cable out solar assistant showed me i have produced 10kwh, but actually in the battery went only 8kwh, you can investigate further but in my opinion if you take out the plug the information is wrong, and actually the real production is the same. 

it depends on how the inverter is set in SBU or SUB! if it is set in any of these, then the solar production first goes to load, then it charges the battery, hence the difference between solar production and battery charging