Hello again,

I'm sorry for being late in this feedback update. I was busier than previous days but I have always kept an eye on the inverter stats.

On 2023/11/30 at 12:03 PM, Coulomb said:

I'm a bit concerned about the gaps in the middle of the day with very low PV current

It came to my attention right in the following day (December 1st) of your last update post that there was no load power at the same time of the gaps in the PV Current graph. So the gaps were totally normal due to near zero load power.

Another thing, after I flashed the 90 V Patch I totally forgot to do a "restore to defaults" for the inverter settings, so the inverter charger never reached the float stage even when batteries (2x Techno Power Tubular Lead Acid) were fully charged. So I just did the reset to test whether the charger would reach the float stage or not, hopefully today!

Attached are the graphs for the past three days were same conditions still apply (very low loads, partially cloudy weather). But I will be putting normal loads (100 - 600 W) on my inverter in the next few days and will be posting graphs again for the last time.

BTW, @Coulomb, do you think we can play with the fans behavior? This model is VERY noisy, even with no loads at all, and is SUPER noisy when charging batteries at 40+ Ampere. Surprisingly, this is still the case even while the inverter now is in a really cold room in winter!

Data Graphs (90 V Patch) Test 1.zip

Edited December 6, 20232 yr by Tarek Y.

On 2023/12/06 at 10:47 AM, Tarek Y. said:

do you think we can play with the fans behavior? This model is VERY noisy, even with no loads at all,

The VM models are renowned for their cheap and noisy fans. I doubt that there is much to be done.

Still, with no load, it may be possible to turn both fans off. I doubt I'll get time to look at this any time soon, unfortunately.

5 minutes ago, Coulomb said:

The VM models are renowned for their cheap and noisy fans. I doubt that there is much to be done.

Yeah, I have seen a lot of other members of this community suffering and complaining a lot of this stupid behavior. I guess the only option I have is to try to replace the fans instead of patching the firmware.

8 minutes ago, Coulomb said:

I doubt I'll get time to look at this any time soon, unfortunately.

No worries, I appreciate all the priceless help you provided to me so far. I'll contact you soon to discuss some patching details.

Anyway, I had great results last day with the 90 V Patch. Even with a very cloudy and rainy day and only a short period of sun, my inverter generated 2900 Wh, because the night before we had no grid electricity input at all, so the batteries were well discharged.

I guess the only issue still existing now, but is no longer affecting my MPPT generation, is the very low current at the start and the end of every day. I'm very happy with the results of your keen work.

I will post (past 3 days data graphs) in a week or so, after I put more loads on the inverter to do deeper battery discharges, and so to get more PV power every day.

Thank you SO MUCH @Coulomb

On 2023/11/25 at 3:18 AM, Coulomb said:

These are patched firmwares version 260.06, 560.06, and 160.06, based on factory firmware version 60.06 for the Axpert VM III Twin 6kW, 4kW, and 1.5kW, and the Axpert VM IV Twin 6kW, 4kW and 1.5kW. These patches implement most of Georg's MPPT "stuck at 90V" patches (here it would be "stuck at 60 V"), and fix the premature float bug. The only parts not applied are for the forward current constant, which doesn't seem to be changed based on solar voltage in any VM firmwares. The version number should display in full when using monitoring software, but will still show as 60.06 on the front panel display. Do not use with any other models, not even older VM III and VM IV models with power ratings like 5 kW or 3 kW, or non-twin models. Use at your own risk.

In the reflash tool, you may have to navigate to the folder with the patched files the first time it is run. Choose the hex file with the voltage you want, 200V, 150V or 100V. Use 200 V if your PV panels are nearly always well above 200 V. Otherwise, use the 150 V version if your panels are almost always above 150 V. Use the 100 V version if your panels are particularly low in voltage.

You can also of course choose the original factory firmware.

Firmware upload instructions.

 

dsp_x60.06_patched_200V_150V_100V.zip 1.29 MB · 7 downloads

Hie Boss how are you

I’m looking for Axpert VM IV firmware because my SVolt Lithium Battery can communicate with firmware from 2022 till date 

thank you a lot 

I need to know your existing display (U2) firmware version, or if you have the Twin or non-Twin VM IV model. 

Just to conclude for this thread. I didn't post any more updates with stats from my inverter back at the time because I suspected that I had a hardware issue with my inverter's PV input, and I can totally confirm it now and since back then.

Unfortunately, it was a result of a very bad repair that took place when my inverter was brand new (it got short circuited) and caused wrong/fake PV input data and more issues are rising now and I'm in the process of fixing all issues, or I will have to replace the whole unit if the progress is not a complete success.

I can confirm now that PV input current and power were not accurate at all in all of my previous graphs and stats. Actual PV input was much more than what was reported by the inverter.

Hello! I still can't wrap my head around what "stuck on 90V" or other voltages mean 🙂
Does this look like this issue?
Lower bound voltage at dawn is wobbling around 60V and doesn't produce any usable power for a while (especially visible at the 10th of June graph, second day on the picture)
Then it suddenly rises
Maybe it's my panels position, but just to be sure -- does it seem like misbehaving MPPT tracker?

Thanks!

On 2024/06/14 at 4:50 PM, WallK said:

Does this look like this issue?

You haven't got it too bad on those graphs. Yes, on the tenth of June you had it for about 10 minutes, when the PV voltage was ruler flat, but then the current was less than an amp, so you didn't miss much.

It's mainly cloudy days that owners notice it; it can stay at 90 V (or 60 V on VM III/IV) for hours. Then suddenly the voltage triples and the PV power triples with it.

I believe that I can recognise the code that works pretty well now. And sadly none of 60.89, 60.95 and 70.00 seems to have it.

Do you happen to have some records from a cloudy day?

3 hours ago, Coulomb said:

I believe that I can recognise the code that works pretty well now. And sadly none of 60.89, 60.95 and 70.00 seems to have it.

Do you happen to have some records from a cloudy day?

I have 60.66 installed

Two previous days were cloudy and very cloudy
Here are voltage and current graphs for those


I don't have enough power storage to survive on solar only two days like this in a row, so I imported some power from grid

 

  

3 hours ago, Coulomb said:

Yes, on the tenth of June you had it for about 10 minutes, when the PV voltage was ruler flat, but then the current was less than an amp, so you didn't miss much.

I think that part was a data gathering issue (if we are talking between 7:00 and 8:00), it has only two datapoints for 10 minutes, so this is why it's so flat there 

Edited June 15, 20242 yr by WallK

On 2024/06/15 at 11:03 PM, WallK said:

I have 60.66 installed

Unsurprisingly, it's the same as other 60.xx; it has the current control parameter (which the early implementations lack), but not what I'm now considering the "full fix".

[ Edit: Oops! That was an error in my disassembly. Sigh. It doesn't even have the current control parameter. So the good performance is likely due to the ideal PV voltage, I'm now thinking. ]

But you don't seem to be losing much of any significance on those particular cloudy days either. So maybe the current control parameter is the main improvement. 

On 2024/06/15 at 11:03 PM, WallK said:

I think that part was a data gathering issue (if we are talking between 7:00 and 8:00), it has only two datapoints for 10 minutes, so this is why it's so flat there 

Ah. I should have realised when it was so very flat. Thanks. So that's even less time where you might have been missing out on solar production.

Or maybe you just have "sweet spot" panel voltage or something. Not too many, but enough.

Edited June 17, 20242 yr by Coulomb

21 hours ago, Coulomb said:

Unsurprisingly, it's the same as other 60.xx; it has the current control parameter (which the early implementations lack), but not what I'm now considering the "full fix".

But you don't seem to be losing much of any significance on those particular cloudy days either. So maybe the current control parameter is the main improvement. 

Ah. I should have realised when it was so very flat. Thanks. So that's even less time where you might have been missing out on solar production.

Or maybe you just have "sweet spot" panel voltage or something. Not too many, but enough.

I've sized it so it's close to the 500V edge in winter, 9S 45.6V per panel at 25C
Should be 456V or so max in winter with -20

If this is close to ideal tracking -- I would love for it to stay that way 🙂
My VM3 twin inverter is also suffering from "premature float" bug, which irritates me immensely
And earlier (and some newer) firmwares have reintroduced "still charges from grid even on Solar only and in SBU mode" bug too

So, what firmware would you suggest I get? Should it have your "stuck" fix, if yes -- what voltage should I use to get maximum out of my installation, especially in winter?
Will you patch the newer ones with fan control at some point?

Thank you!

5 hours ago, WallK said:

I've sized it so it's close to the 500V edge in winter, 9S 45.6V per panel at 25C
Should be 456V or so max in winter with -20

That's presumably Voc, not Vmp?

Note that I have found that I made a mistake in my 60.66 disassembly. It turns out that 60.66 and most if not all of the 60.xx series and 70.00 don't have the current forward control, which is my latest guess at what makes a good factory firmware. So I'm now thinking that your good MPPT performance is due to the ideal number of panels (and hence ideal Vmp). Sorry for the bad info.

Quote

My VM3 twin inverter is also suffering from "premature float" bug, which irritates me immensely

Do you have a VMIII as well as a VM IV?

If so, what main (U1) firmware version does the VM III run?

Quote

So, what firmware would you suggest I get?

I'm still looking into that.

Quote

Should it have your "stuck" fix, if yes -- what voltage should I use to get maximum out of my installation, especially in winter?

If it's connected to the 9S string described above, then the highest possible voltage, which is likely 200 V.

Quote

Will you patch the newer ones with fan control at some point?

That could happen. I'm stuck on other projects at present.

 

14 hours ago, Coulomb said:

That's presumably Voc, not Vmp?

Of course, I just sized it for the "not burn the inverter" 🙂

14 hours ago, Coulomb said:

Note that I have found that I made a mistake in my 60.66 disassembly. It turns out that 60.66 and most if not all of the 60.xx series and 70.00 don't have the current forward control, which is my latest guess at what makes a good factory firmware. So I'm now thinking that your good MPPT performance is due to the ideal number of panels (and hence ideal Vmp). Sorry for the bad info.

So it's finally doesn't require a fix?

14 hours ago, Coulomb said:

Do you have a VMIII as well as a VM IV?

If so, what main (U1) firmware version does the VM III run?

Only VMIII, I just hijacked the thread, firmwares were the same before the last one iirc

14 hours ago, Coulomb said:

If it's connected to the 9S string described above, then the highest possible voltage, which is likely 200 V.

So the idea is -- it will start tracking from 200V? And my blimps of energy early morning on cloudy days will be gone?

14 hours ago, Coulomb said:

That could happen. I'm stuck on other projects at present.

I could imagine, how much is there of us and only one you 🙂 Thank you!

@WallK,

According to our approach of this bug, in order to consider your inverter's MPPT tracker stuck at some voltage, it should stay at that voltage for some considerable amount of time without producing any PV power, like for 20 minutes or more. Mine was getting stuck for more than an hour for each sunrise and sunset back then. But eventually, and unfortunately very late, I found out that most of the 'stuck' time was false as there were some serious hardware problems I have in my inverter due to a very bad old repair

On 2024/06/18 at 9:05 AM, WallK said:

Of course, I just sized it for the "not burn the inverter" 🙂

I would never recommend such a setup, as every inverter model has it's own "Nominal PV Voltage" which is the point where you might get the maximum power out of your PV panels at that specific voltage (Vmp). You can find it in the specifications section in the user manual, or on the sticker of your inverter.

On 2024/06/18 at 9:05 AM, WallK said:

So the idea is -- it will start tracking from 200V? And my blimps of energy early morning on cloudy days will be gone?

No, it will start tracking right when the PV panels voltage is in your inverter's MPPT range, just as standard. But, it will start withdrawing power right at 200 V instead of the set voltage in the original firmware, this is what the patch is all about. Don't get too distracted by the numbers, according to your panels setup, it's not that high voltage, it still is a matter of minutes for you.

19 hours ago, Tarek Yag said:

According to our approach of this bug, in order to consider your inverter's MPPT tracker stuck at some voltage, it should stay at that voltage for some considerable amount of time without producing any PV power, like for 20 minutes or more. Mine was getting stuck for more than an hour for each sunrise and sunset back then. But eventually, and unfortunately very late, I found out that most of the 'stuck' time was false as there were some serious hardware problems I have in my inverter due to a very bad old repair

Mine doesn't do this as far as I can see, right?
I guess I jump through that set voltage too fast to notice

 

19 hours ago, Tarek Yag said:

I would never recommend such a setup, as every inverter model has it's own "Nominal PV Voltage" which is the point where you might get the maximum power out of your PV panels at that specific voltage (Vmp). You can find it in the specifications section in the user manual, or on the sticker of your inverter.

It worked out somewhere in the range
My invertor specifies 350V nominal and my panels are rated for 345Vmpp, in real world my tracker wobbles around 330-360
I've heard some advice that you should get a little higher than nominal max power voltage, but in my calculations Voc became a problem before I could get to the nominal MPPT tracker voltage with Vmp
With these specific panels it all worked out almost perfectly!

4 minutes ago, WallK said:

Mine doesn't do this as far as I can see, right?

Exactly right!

5 minutes ago, WallK said:

My invertor specifies 350V nominal and my panels are rated for 345Vmpp, in real world my tracker wobbles around 330-360

This is a perfect setup!

5 minutes ago, WallK said:

but in my calculations Voc became a problem before I could get to the nominal MPPT tracker voltage with Vmp

Totally expected and normal, you nailed the perfect numbers already! Good for you. You don't need to get any higher than the nominal MPPT voltage, you're already in the perfect range.