a small update between the total power produced from the panels between Solax and Aexpert Max II 10Kw

iI will post the graph between the two inverters so that we can see how it behaves in the evening and the total produced from solar panels

unfortunately, Solax does not monitor individual voltage and amperage to see the exact instantaneous voltage/amperage ratio between the 2 inverters in real time

Edited December 31, 20223 yr by ClauBebe

Interesting. The Axpert still has a long way to go, I think. The Solax did way better before the Axpert "woke up" at 9:45.

I find it interesting that the PV power of MPPT1 seems to decay from the peaks (presumably forced there by the resets) much more quickly than MPPT2. So one minute resets would be better than 5 minutes for MPPT1 in these conditions, perhaps even shorter would be even better. But that might wreck more common conditions, we'll have to see.

Forgive me, is this with "plug in" or "unplugged"?

I presume my Kodak OG10 is the same as the Axpert Max? If so I see that my PV voltage also stays below 90V and then suddenly wakes up. 
 

3 hours ago, Coulomb said:

Forgive me, is this with "plug in" or "unplugged"?

yes, both inverters are connected to the grid at that moment with full house load. Solax is a permanent ongrid without storage and the Aexpert was set to SUB

2 hours ago, VanWykAC said:

I presume my Kodak OG10 is the same as the Axpert Max? If so I see that my PV voltage also stays below 90V and then suddenly wakes up. 

what firmware version do you have? U1 and U2 ?

 

3 hours ago, Coulomb said:

But that might wreck more common conditions, we'll have to see.

that's why I'm afraid...repeated starts to lead to a lack of power and a "jumpy curve"

I will come back with more comparative graphs between the 2. Overall, Solax is much more productive than Aexpert on cloudy days

The Aexpert beats it only on sunny days due to the much better positioning of the panels, all facing south, while the Solax has 5 panels facing west

Edited December 31, 20223 yr by ClauBebe

On 2022/12/29 at 7:39 AM, Coulomb said:

Good idea, and easy to implement. It eliminates one change.

This is patched firmware version 656.05 (yes, I had to use a different method to make the version number come out > 655.36, the limit for 16 bits). It's identical to 556.05, except that the resets are considered every minute instead of every 5 minutes. In the mornings and afternoons, 5 minutes is a long way up or down the ramp.

Use at your own risk.

OG-10 DSP Reflash_656.05 patched.zip 1.6 MB · 4 downloads

Here are the diagrams with the latest firmware compared to other versions. The latest version starts generating power earlier and ends later!

Inverter 1 00056.06 (Georg)

Inverter 2 00656.05 (latest version)

Inverter 3 00056.05 (not used)

Inverter 4 00056.05 (original)

Inverter 5 00465.05 (second to last version)

Inverter 6 00056.06 (not used)

 

...and today. I hope it's not too confusing.

 

As we can see from the diagrams, there are actually only 3 voltage ranges. Below 60 V "nothing works" - here the voltage is not sufficient to be raised to the necessary bus voltage (is ok).
Then comes the clamping (90 V), above this there is sometimes a drop back to 90 V or the voltage rises quickly to the operating point.
From 170 V, there are no more problems - the operating point above this is quickly found.

Unfortunately, the implemented MPPT algorithm is not good. As I see it, the PV voltage should rise fast and continuously. In the morning and evening, a short circuit is always generated: voltage and power collapse to zero. Couldn't we just lower the minimum current further to close the gap?
(Even if it is only a few watts per hour).

(I have just installed the latest version in 3 inverters. Inverter 4 (only PV2) remains on the original version. This means that I can test a wide range of alignment of the PV fields and strings with 4 to 10 modules).

17 hours ago, ClauBebe said:

17 hours ago, Coulomb said:

Forgive me, is this with "plug in" or "unplugged"?

yes, both inverters are connected to the grid at that moment...

Sorry, I should have been clearer. I meant have you made the hardware modification suggested by Georg, where you open up the inverter and take the plug out of the socket marked "Solar" that supplies HFPW+ (high frequency power) to the MPPT helper power supply board?

Details in this post.

I know someone said they didn't want to open their inverter, and that's fair enough, but I can't remember if it was you. Searching for such things is a pain; there are so many ways of describing it, and there are several threads where this could be mentioned.

On 2022/12/31 at 8:37 PM, VanWykAC said:

I presume my Kodak OG10 is the same as the Axpert Max?

It should be the same as an Axpert Max 1 10 kW, and your main firmware version number is familiar, but I've never heard of display firmware version 35.xx. Fortunately, all the action is in the main DSP firmware at present, e.g. the stuck at 90 V problem. You could try patched firmware version 656.05, though you'd lose any improvements made between 56.05 and 56.07, and there is no easy way of extracting your existing firmware.

Edit: Oops, I've just realised that my notes say that 56.05 is Max II, not Max 1. Now I don't know where I got the Max 1 idea from. I assume that yours has the round colour display, not the removable display?

Edit 2: It's Max II, confirmed below.

Edited January 9, 20242 yr by Coulomb

1 hour ago, Coulomb said:

Sorry, I should have been clearer. I meant have you made the hardware modification suggested by Georg, where you open up the inverter and take the plug out of the socket marked "Solar" that supplies HFPW+ (high frequency power) to the MPPT helper power supply board?

Details in this post.

I know someone said they didn't want to open their inverter, and that's fair enough, but I can't remember if it was you. Searching for such things is a pain; there are so many ways of describing it, and there are several threads where this could be mentioned.

No hardware modification, just software with your QFW. I don't have any problems to open my inverter, 🤣😉

I don't know that post with modification, I will look at it 

 

 

Edited January 1, 20233 yr by ClauBebe

a small update between Solax and Aexpert Max II 10 Kw sunny day

I also managed to find the graphics from Solax

PV1 Solax is similar with my PV1 and PV2 Aexpert configuration
PV2 Solax has 5 pieces facing west, here is the difference in voltage/amperage between PV2 Solax and PV2 Aexpert

At Solax, it can be seen that at the beginning of the day the voltage increases almost to the maximum of ~ 350 Vdc without any amperage, after which it drops to ~ 100 Vdc and the amperage starts to rise as the voltage also rises

 

Edited January 1, 20233 yr by ClauBebe

1 hour ago, ClauBebe said:

At Solax, it can be seen that at the beginning of the day the voltage increases almost to the maximum of ~ 350 Vdc without any amperage,

Huh, that sounds suspicious. Especially PV2 with only 5 panels, generating almost 320 V. My guess is that the electronics isn't good at measuring PV voltage when the PV current is very low to non-existent. Weird that it registers anything at all though.

9 minutes ago, Coulomb said:

Huh, that sounds suspicious. Especially PV2 with only 5 panels, generating almost 320 V.

PV2 Solax does not only have 5 panels, it is exactly like the other strings, only 5 of them are oriented to the west due to the lack of space on the roof

8 hours ago, Coulomb said:

It should be the same as an Axpert Max 1 10 kW, and your main firmware version number is familiar, but I've never heard of display firmware version 35.xx. Fortunately, all the action is in the main DSP firmware at present, e.g. the stuck at 90 V problem. You could try patched firmware version 656.05, though you'd lose any improvements made between 56.05 and 56.07, and there is no easy way of extracting your existing firmware.

Edit: Oops, I've just realised that my notes say that 56.05 is Max II, not Max 1. Now I don't know where I got the Max 1 idea from. I assume that yours has the round colour display, not the removable display?

Yes, mine has the round display

 

9 minutes ago, ClauBebe said:

it is exactly like the other strings, only 5 of them are oriented to the west due to the lack of space on the roof

Ah, OK. But I imagine that it amounts to much the same thing in the mornings, when there would be essentially no sun on the 5 west facing panels.

 

10 minutes ago, Coulomb said:

Ah, OK. But I imagine that it amounts to much the same thing in the mornings, when there would be essentially no sun on the 5 west facing panels.

up to a certain point when the sun rises a little they are equal

 

Edited January 1, 20233 yr by ClauBebe

predominantly sunny day comparison between Solax and Aexpert Max II QFW 656.05 for a whole day as well as in the evening

PV1 Solax is similar with my PV1 and PV2 Aexpert configuration
PV2 Solax has it is exactly like the other strings, only 5 of them are oriented to the west due to the lack of space on the roof, here is the difference in voltage/amperage between PV2 Solax and PV2 Aexpert

 

Edited January 1, 20233 yr by ClauBebe

Interesting that the Axpert MPPTs both found a small surge in power towards the end of the day by suddenly going to minimum MPPT voltage (90 V). My guess is that they briefly found the true MPPT, then shot right past it in the rush for 90 V. That suggests to me that they should really have been decreasing panel voltage for tens of minutes before that. IV versus irradiance curves suggest that the voltage should fairly gradually decrease with decreasing irradiance, falling to about 75% of Voc (some 85% of Vmp) at 20% irradiance. So the cliff fall that we see can't be optimal.

The question is: what relatively simple changes can be make to improve the algorithm? Attempting a complex algorithm on a model that I don't own would be asking for trouble, it seems to me.

 

8 hours ago, Coulomb said:

The question is: what relatively simple changes can be make to improve the algorithm? Attempting a complex algorithm on a model that I don't own would be asking for trouble, it seems to me.

unfortunately I don't "speak" the language of inverters ... all I can do is to put as detailed graphs as possible to see the behavior of the inverter

anyway, the Aexpert behaves very well with QFW 656.05 compared to the original firmware FW56.05

Canadian Solar-Datasheet-HiKu_CS3L-MS_EN , I have 20 pics 375w, 10* 375w on string / MPPT1 and MPPT2

Edited January 2, 20233 yr by ClauBebe

On 2023/01/01 at 5:24 AM, Coulomb said:

Sorry, I should have been clearer. I meant have you made the hardware modification suggested by Georg, where you open up the inverter and take the plug out of the socket marked "Solar" that supplies HFPW+ (high frequency power) to the MPPT helper power supply board?

Details in this post.

I know someone said they didn't want to open their inverter, and that's fair enough, but I can't remember if it was you. Searching for such things is a pain; there are so many ways of describing it, and there are several threads where this could be mentioned.

Today I looked at countless recordings (also old ones with the original firmware). After reading the message about the suspected interference (connector "SOLAR"), I can possibly explain some strange behaviour (e.g. the interference between the two PV inputs).

With version 656.05 (I have been using it for 6 PV strings since last night), the fluctuations in the lower range are simply too great for me.
If I have interpreted the many data correctly, it would have been enough if the voltage was only changed "by force" when it was between 89.5 and 91 V, for example. (Actually, the 90 V value only varies by minus one digit to plus two digits around 90V).
It is sufficient if the voltage value is set to more than 107 V (possibly less is also sufficient, the diagrams are not so easy to interpret).

I will first open the inverter and disconnect the connector. Let's see if there is an effect!
Later I could also build a small filter (bifilar choke and capacitor, insulated with heat shrink tubing) to loop in....

On 2022/12/29 at 7:39 AM, Coulomb said:

Good idea, and easy to implement. It eliminates one change.

This is patched firmware version 656.05 (yes, I had to use a different method to make the version number come out > 655.36, the limit for 16 bits). It's identical to 556.05, except that the resets are considered every minute instead of every 5 minutes. In the mornings and afternoons, 5 minutes is a long way up or down the ramp.

Use at your own risk.

OG-10 DSP Reflash_656.05 patched.zip 1.6 MB · 4 downloads

I am now very sure, there are actually two fixed clamping states. One is fixed at 90V - here there seems to be no regulation of the MPPTs - and in the second, the voltage fluctuates between 90 and 107 V - here the MPPTs are active. Below 90V no power is generated (see data sheet MPPT range is 90...450V).

It will be sufficient to check if the voltage is between 89.5 and 107V and then add 10V.

This way the intervention in the algorithm would not be so strong.

19 hours ago, Volker said:

With version 656.05 (I have been using it for 6 PV strings since last night), the fluctuations in the lower range are simply too great for me.

This is great data; I bet even Voltronic R&D don't have 6 strings of PV in various weather conditions!

Just so I can be clear on what is needed, what do you mean by fluctuations in the lower range? Do you mean when the PV voltage is say 120-170 V, the resets are setting the voltage to max so often that you end up losing solar energy production?

I worry that the 175 V threshold is specific to a particular string configuration, and may not be appropriate for longer or shorter strings of panels / total cells. Your suggested values, all quite low values, seem to me to have a better change of working for most panel configurations.

In the morning and evening, a working point of around 100 volts can be OK. Then setting  of the voltage causes dips downwards (unnecessary fluctuations and losses).

As already mentioned, there are actually only 3 working points:
1. 90 V fixed MPPT delivers power but does not regulate.
2. 90 to 107 V MPPT supplies power but regulates.
- Both states can be "stuck" !!
3. It jumps (!) to the voltage corresponding to the string voltage (smaller than VOC according to the number of PV modules and the PV characteristic curve). Now the MPPT reach into the in "Maximum Power Point".

In the first two states, the "forcible" setting of the voltage causes a drop in the power.
Yes, it can also occur in state 3. My string with only 4 modules shows this behaviour.

Therefore, I had already recommended only intervening when the controller algorithm is in state 1 and 2 (see previous message). Also, the increase of the voltage should be as small as possible.

On 2022/12/30 at 8:17 PM, ClauBebe said:

With QFW 656.05 I caught a cloudy and rainy day with very weak sunlight
Compared to the Solax that I monitor and which works at maximum capacity, which today produced only 0.80kWh all day, my system produced 0.90kWh, something that never happened to me with the original firmware, which remained stuck in 90v for a day like this, and it didn't produce anything only if I keep resetting it manually
I am attaching the comparative graphs between the 3 QFW 456.05, 556.05, 656.05

and here the whole chart for today, cloudy and rainy day with QFW 656.05

 

I'm curious to see Volker's graphs, which can track in real time the behavior of the 2 firmwares QFW456.05 and QFW656.05

Attention - Attention - Attention

When the SOLAR cable is disconnected at the SPS, EVERYTHING changes!

The two blue curves are the inverter with the cable disconnected!
Red is the original firmware, otherwise all on version 656.05.

Edited January 4, 20233 yr by Volker