SRNE Odd MPPT Charging Behavior - Pause Every 12 Minutes?

Aerial Gopher · Jul 19, 2022

Wondering if this is normal behavior for MPPT. The sharp drop off on the right was a one of them pesky clouds

But this drop to 0 PV

The inverter is a SRNE 3Kw 24v system, 120 volt out.

While in between these 12 minute intervals, the voltage and wattage does change and does appear to track properly. I have not seen these drops to 0 on other MPPT charge controllers.

This is not an artifact of Solar Assistant graphing this wrong, I have verified this behavior by watching it on the screen of the inverter too.
This is not caused by battery's not accepting a charge because others have been used in place of the current ones, and the same behavior exhibited.

FYI - Solar Assistant is AWESOME!

DThames · Jul 19, 2022

Looks odd to me. What is your array size in watts? Is the array watts small compared to the charger's rating?

Aerial Gopher · Jul 19, 2022

DThames said:
Looks odd to me. What is your array size in watts? Is the array watts small compared to the charger's rating?

The array was 610 ( 2x310 ) and now is 1500 watt with more panels, it has been doing this before as well as now.
The max PV input is 1600 watt, and max Voc is 100vdc which the panels and set up is below both those limits.

So I have had a small array, and one that near maxes out the charge controller.

On a 170 watt load on the inverter, the total draw from batteries is between 80 - 90 watts more to run the inverter. Was not happy about that.
Im in talks with the seller on Aliexpress, and they claim all of this is normal, but we have all been down that road before.

Don B. Cilly · Jul 19, 2022

They might be MPPT "sweeps". My Tracer does that, but every couple of days or so.
12 minutes seems rather absurd, but... you never know with software.
Have you tried resetting the SCC?
-

Aerial Gopher · Jul 19, 2022

Don B. Cilly said:
They might be MPPT "sweeps". My Tracer does that, but every couple of days or so.
12 minutes seems rather absurd, but... you never know with software.
Have you tried resetting the SCC?
-

SCC? sorry not familiar with all the acronyms of solar stuff yet. I'm guessing you mean the charge controller? complete disconnect and reconnect, I have not done the reset to factory defaults on settings. There is no setting i have seen that has a 12 minute or similar value on it either.

DThames · Jul 19, 2022

Solar Charge Controller SCC. It might be "normal" for the way they wrote the MPPT logic. It will need to find the greatest power point and adjust. Looks like it dumbly starts from scratch every 12 minutes, with a heavy load to test the current (maybe) then adjusts accordingly. I do see a couple of places where the dip is not as deep. Any idea what is different there?

Aerial Gopher · Jul 19, 2022

DThames said:
Solar Charge Controller SCC. It might be "normal" for the way they wrote the MPPT logic. It will need to find the greatest power point and adjust. Looks like it dumbly starts from scratch every 12 minutes, with a heavy load to test the current (maybe) then adjusts accordingly. I do see a couple of places where the dip is not as deep. Any idea what is different there?

polling time of Solar assistant. It does definatley go to 0 on the screen of inverter when watching it happen in real time

DThames · Jul 19, 2022

Looking closely at the Voltage curve, he unloads, then heavy loads, then settings to normal, every 12 minutes.

Looks like a rookie MPPT programmer in the firmware.

edited to say Voltage curve.

Aerial Gopher · Jul 19, 2022

Do you think this might be caused by the USB and Solar assistant being plugged in? I know seems like a unlikely scenario, but I might try to unplug it and watch it for more than 12 minutes to see if it still does this......

UPDATE: Nope still does it after USB cable unplugged, hmmm wierd issue

Aerial Gopher · Aug 10, 2022

So the SRNE Inverter SUX here is the graph with SRNE on the left, and Growatt on the right. The drop off at about 2 - 4 pm was due to battereies being full, and no PV needed. But the drop out every 12minutes is not there on the GroWatt that I got from WATTS247.com ( Awesome quick service from him BTW)

you will see on the Growatt there was none of that odd behavior.

I WILL say that I WISH I had gotten the growatt SPF 3000 watt first, it is so quiet compared to the SRNE. The SRNE did have variable fans, but it based fan speed on load rather than temp. Its actually peaceful now with the GroWatt. I really cant describe it, the fans run at low rpm and thus no real loud noise. Even with1400 watt PV input the fan speed was pretty low, and 10% of what the SRNE fans were ramped up to.

Returned the SRNE to aliexpress for full refund. The seller refused to do anything after just over 1 month of messages back and forth. The GroWatt was actually a better prie from WATTS247.com than aliexpress, including shipping to me! I feel like a fool for not going that route first.

wattmatters · Aug 11, 2022

That's just looks like a really crappy MPPT algorithm on the SRNE. With any luck it's fault only with your specific inverter and not something endemic to that model/brand.

Aerial Gopher · Aug 11, 2022

wattmatters said:
That's just looks like a really crappy MPPT algorithm on the SRNE. With any luck it's fault only with your specific inverter and not something endemic to that model/brand.

Seller on Aliexpress was shown this, given the opportunity to replace the unit. They dragged that conversation on for 5 weeks. Thankfully it had free return, and they paid for shipping.

This is the seller, and I would ** NOT ** deal with them on anything. They dragged out the conversation in chat messages for 5 + weeks and just kept avoiding dealing and fixing this issue.

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Wakintx · Jan 21, 2023

I have 3 of these SRNE AIOs, no 12 minute pause. 1700w of panels, I don't hear the fans often but they are in spare bedroom/dressing room/exercise with open door. Occasionally hear them come on while I am in the room, slow then ramp up. Then usually cut off after several minutes. Loud enough to know they are on.

Probably louder than my 12volt component 1800w inverter but I don't have a decibel meter.

You definitely had a bad seller and I believe a defective unit. Since my seller is in the US, return would probably be easy. They are helpful company but other than asking if they stock the WiFi dongle I have had no reason to really contact them...

Another reason I've avoided AliExpress. Unfortunately some vendors are good, others sux

Sleeper85 · Feb 11, 2023

I have an EAsun SMX II 5.6kW which is a rebranded SRNE HF4850S80-H (48V 5600VA).

Firmware: 6.17
Bootloader: 2.01

I observe the same phenomenon in Solar Assistant but every 30 minutes.
I don't find it normal either and I think this could be fixed with a new firmware...

I contacted SRNE technical service and here is their response:

hi sir,

It is normal for solar charge inverter,every 30 minutes,the solar charge inverter will scan the PV once globally to achieve the maximum input power.

have a nice day.

When the problem occurs the PV icon flashes for 1 minute.

08_PVPow - SCC MPPT freeze every 30 min.png

08_PVVolt - SCC MPPT freeze every 30 min.png

Sleeper85 · Feb 11, 2023

Wakintx said:
I have 3 of these SRNE AIOs, no 12 minute pause. 1700w of panels, I don't hear the fans often but they are in spare bedroom/dressing room/exercise with open door. Occasionally hear them come on while I am in the room, slow then ramp up. Then usually cut off after several minutes. Loud enough to know they are on.

Probably louder than my 12volt component 1800w inverter but I don't have a decibel meter.

You definitely had a bad seller and I believe a defective unit. Since my seller is in the US, return would probably be easy. They are helpful company but other than asking if they stock the WiFi dongle I have had no reason to really contact them...

Another reason I've avoided AliExpress. Unfortunately some vendors are good, others sux

You and also @Mattb4 say you have never seen this with your AIO.
And if that's really the case that's good and it gives me hope for a new firmware.

Personally I think that without Solar Assistant I would never have noticed either...

As for the WiFi datalogger dongle, don't buy this, it's a crap that sends your data to a cloud with a badly made application.
Solar Assistant is 100x better.

And you can also connect your SRNE to Home Assistant :

Integrating SRNE MPPT Inverter with HA

So I was looking for a way to get data from my SRNE Solar charge inverter. And after looking into some bluetooth adapters and different modbus configurations I decided to give it a shot. I have never looked into modbus before but after reading this thread I ordered a waveshare RS485 to ethernet...

community.home-assistant.io

Wakintx · Feb 11, 2023

Sleeper85 said:
You and also @Mattb4 say you have never seen this with your AIO.
And if that's really the case that's good and it gives me hope for a new firmware.

Personally I think that without Solar Assistant I would never have noticed either...

As for the WiFi datalogger dongle, don't buy this, it's a crap that sends your data to a cloud with a badly made application.
Solar Assistant is 100x better.

And you can also connect your SRNE to Home Assistant :

Integrating SRNE MPPT Inverter with HA

So I was looking for a way to get data from my SRNE Solar charge inverter. And after looking into some bluetooth adapters and different modbus configurations I decided to give it a shot. I have never looked into modbus before but after reading this thread I ordered a waveshare RS485 to ethernet...

community.home-assistant.io

I WILL Have to observe it, I have not implemented any monitoring ?

wattmatters · Feb 11, 2023

Sleeper85 said:
I observe the same phenomenon in Solar Assistant but every 30 minutes.
I don't find it normal either and I think this could be fixed with a new firmware...

Is see nothing like that.

Screen Shot 2023-02-12 at 12.15.51 pm.png

Sleeper85 said:
it gives me hope for a new firmware

I would be very hesitant to upload any firmware without being absolutely certain it has been tested thoroughly as working on your specific model. There are so many variations of hardware/firmware and many have had their unit bricked with no way to undo it.

Sleeper85 · Feb 11, 2023

Yes I was interested in those who bricked their AIO and I hope they will manage to put it back in service. And it is clear that I am very hesitant to do an upgrade without having received a firmware from a reliable source and with a changelog.

The only thing you can see by looking at your screen is the PV icon flashing and the PV voltage sticking to a high value before dropping back down and then starting again normally like in the picture posted above where I have circled in red the voltage which rises, remains stable for a moment then falls before rising again.

Sleeper85 · Feb 11, 2023

wattmatters said:
Is see nothing like that.

View attachment 134412

I would be very hesitant to upload any firmware without being absolutely certain it has been tested thoroughly as working on your specific model. There are so many variations of hardware/firmware and many have had their unit bricked with no way to undo it.

Is the graph you posted your setup? Have you installed Solar Assistant?

wattmatters · Feb 11, 2023

Sleeper85 said:
Is the graph you posted your setup? Have you installed Solar Assistant?

Yes, that is a Solar Assistant graph from yesterday's production of my EASun 8kW. I only have a small 2.2 kW array feeding it at present.

Sleeper85 · Feb 11, 2023

wattmatters said:
Yes, that is a Solar Assistant graph from yesterday's production of my EASun 8kW. I only have a small 2.2 kW array feeding it at present.

OK, I made a mistake, I thought I was answering @Wakintx who has an AIO SRNE.

Your EAsun is connected with Solar Assistant with the Voltronic or SRNE protocol?

wattmatters · Feb 12, 2023

Sleeper85 said:
Your EAsun is connected with Solar Assistant with the Voltronic or SRNE protocol?

Voltronic. It's essentially the same inverter as the MPP 8048MAX.

Sleeper85 · Feb 12, 2023

After having carefully analyzed what is happening, as SRNE told me by e-mail.
This is indeed a sweep of the MPPT to find the maximum power point.

On the graphs below, we can see that this scan starts at 1:29 p.m. and ends at 1:31 p.m.

Before 1:29 p.m. the power is +/- 200W and after 1:31 p.m. the power is +/- 230W, so we can say that the MPPT has found a better point. (no sun today at my place)

In my case it's a 120V to 450V MPPT.

From 1:29 p.m. the SCC starts looking for the Vmp voltage and the voltage rises (but not to Voc which is 290V at that time) then the voltage goes down to 120V which is the low voltage of my MPPT (seen on the screen ) before going up to Vmp.

What I find stupid is that when the MPPT starts scanning towards a higher voltage and it doesn't find better power, it should drop right back down instead of continuing to climb even higher and lose even more power.

Solar Assistant shows that other AIOs don't have this behavior so yes, we can say that the MPPT algorithm is unfortunately not great.

Yet I know that SRNE makes good MPPT SCCs that are widely used around the world. Strange...

That said, I don't want to generalize and it may be related to my model / firmware...
I remain convinced that this can be corrected with a new firmware.
On the other hand, I am less convinced to have soon a new firmware. ?

Sleeper85 · Feb 12, 2023

Interesting post about how an SCC MPPT works.
Mine behaves like point 2) so fulll sweep.

How does MPPT work? - Solar Panels - Solar Panels Forum

For people who have experience with solar panels and/or work in the industry. Discuss installation questions here.

www.solarpaneltalk.com

So how do you replace this clever man with an algorithm? There are three basic ways I know of:

1) Simple backoff from OCV. Most panels produce their maximum power at about 80% of their OCV. So a simple way to implement this would be to disconnect the array momentarily, measure the voltage, then reconnect it and make sure the voltage never dropped below 80% of that value. You have to do this periodically to track changes due to temperature, clouds etc. The old RV Power Products (now Blue Sky Engineering) MPPT chargers did this.

2) Full sweeps. If you ramp your PWM from 0% to 100% you will see a point at which maximum power is produced. Then you limit your minimum voltage to that level. You can't do this if your batteries are close to fully charged because they won't accept all the current you need to run that test - but when you are close to full charge you don't need full power anyway.

3) Small sweeps. At startup you make a reasonable guess as to maximum power point (i.e. you measure the input and output voltages, divide and set the PWM value slightly above that) and then go up and down in both directions. If power increases you keep going in that direction; when power starts decreasing again you reverse direction. Since you can do this continually with very little loss in power you don't have to do anything periodically. This system is harder to stabilize than the above two.

You can also do a hybrid of 2 and 3 - do a full sweep on startup then small sweeps afterwards. The old MX60 did this.

Mattb4 · Feb 12, 2023

Sleeper85 said:
Interesting post about how an SCC MPPT works.
Mine behaves like point 2) so fulll sweep.

How does MPPT work? - Solar Panels - Solar Panels Forum

For people who have experience with solar panels and/or work in the industry. Discuss installation questions here.

www.solarpaneltalk.com

From your symptoms it seems more like #1 since your icon for PV goes off (disconnect from array).

SRNE Odd MPPT Charging Behavior - Pause Every 12 Minutes?

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