Hybrid Gen2 - MPPT tracker performance - With East/West strings

There has been some mention of a possible performance issue within the beta firmware test, so I thought a separate thread on this specific issue would be a good idea.

Simon_C
21 hours ago

TheDragon (GivEnergy) , what is the PV tracker update supposed to achieve?

Multiple, time slots, different Pause method, Both need subsequent portal updates, so wont see till then.
PV Tracker seperation
To name a few. I will sumerise what I get for each inverter.

I have recently swapped out a Solax (non-battery) inverter for the HY5-Gen2 and with East/West strings have noticed the PV string currents do not vary so much over the day on the GE inverter. So far I cannot tell if this is affecting the overall power output as we have not had any clear blue sky days recently.

TheDragon (GivEnergy)
21 hours ago

Simon_C A low input on one tracker can pull down the other. Similar seen on Gen 1 Hybrids too.

Hence i need to test them both

TheDragon (GivEnergy), You, kram, and mattpdavey replied to this.

TheDragon (GivEnergy)
21 hours ago
Edited

TheDragon (GivEnergy)

A perfect text book East/West would be like these (simulated)

Simon_C
21 hours ago

TheDragon (GivEnergy) , is there a specific voltage on 1 of the strings that I should be looking out for?

Presumably at the beginning/end of the day when the West/East facing panels are shaded by the house roof.

TheDragon (GivEnergy)
21 hours ago

Simon_C It seems to be when under 100v, ie one tracker has gone offline.

So if the sun is in the east, morning, the east string shoud be performing, not asleep. Likewise the end of the day, vice versa

You replied to this.

Kkram
21 hours ago

TheDragon (GivEnergy)

But you’re saying it is believed to be fixed in the soon to be released beta-next version of inverter firmware?

Simon_C
21 hours ago

TheDragon (GivEnergy) , this is what I have collected from the Solax inverter on a blue sky day (20/1/2023).
Note - PV1 (dark blue line) is West facing 10x410 W, PV2 (pale blue line) is East facing 6x410 W.

I will see what I can dig out from the HY5-Gen2 logs.

TheDragon (GivEnergy)
20 hours ago

Simon_C almost text book, West biased

You replied to this.

Simon_C
20 hours ago

TheDragon (GivEnergy) , the best I can find in the time I have had the HY5-Gen2 is this.

String1 = West - 10 x 410 W
String2 = East - 6 x 410 W

The graph is somewhat confusing as I cannot change the trace colours.
Before 09:30, the East string is the highest output, after it is the West.
Adding the total power just confuses even more with 3 shades of yellow that are barely distinguishable.

I may be in a unique position having just had my solar inverter swapped from a Solax (non-battery) to the GivEnergy HY5-Gen2 whilst keeping exactly the same panels and DC wiring in place.

Here are some more detailed charts from the Solax, taken from a clear blue sky day this January.

In this case PV2 is the East facing string with 6 x 410 W panels.

First thing in the morning the Voc of the panels comes in to play reaching approx 250 Vdc (6 x 42 V approx).
Then as the insolation increases the MPPT tracker tries to load up the string, so the voltage drops but the current increases from 0, so there is actual power generation.
As the morning progresses the current increases with a pretty flat voltage profile, hence the power reaches a peak at around 10:30 (Approx 250 V x 3.0 A = 750 W), before to drop off to very low values by 14:00.

In this case PV1 is the West facing string with 10 x 410 W panels.

First thing in the morning the Voc of the panels comes in to play reaching approx 400 Vdc (10 x 40 V approx).
There is a period with relatively low voltage and current until around 11:00, after which both the voltage and current increase up to the peak at 14:00 (Approx 400 V x 3.0 A = 1200 W).
Then as it is January, there is the steep drop off to 0 W by around 16:00.

In comparison now with the HY5-Gen2, the voltage/current profile is very different. Not saying either method is wrong, but we all need the highest power output possible, and that is down to the performance of the MPPT trackers in the inverter for each string.

The GE power charts on the web portal are not very clear, so I exported the raw data for an example day then inserted in a spreadsheet and added some charts. I cannot work out multiple scales yet, so the current values are shown in more detail on the second chart.

Admittedly this was not a clear blue sky day, but the best I could find so far.
There is no high peak of voltage at the morning startup, and the string current profiles are very different.
The power only rose from 0 in the morning once both strings got above approx 150 V, which is a good 40 minutes after string 2 (East) got to the startup voltage of 150 V.

@joshgreenuk has done some good work documenting this on Gen1 beta FW too.
Looks to be the same tracker control issue.

Which the latest Gen2 FW delivered last night is said to address.
But till tested I'm not declaring it fixed.

Dan From GivEnergy has Gen2 Hybrid so pretty sure it'll be loaded now to his own.

I shall follow with interest, got 6.3kwp being installed evenly between east and west in 23 days, not that I'm counting or anything.

dbt85 East West has the best overall potential IMHO.

Not as high output as a South facing. But over longer time

We have 5kwp on the east and the same on the west. Due to have a gen 2 5kw hybrid inverter retrofitted the week after next so if you need someone else please let me know. I've been critical of GE over the last several months but at the same time very keen to see it fixed for everyone's sake. So happy to help. We did volunteer a while back and were told we were on the beta, but the firmware was never changed. Please message if you need more testers. I can't promise to give the same level of granular detail as others as I'm very busy, but I'll do my best.

TheDragon (GivEnergy) Not only that, when so many are getting capped at 3.68 export, you're going to hit that cap less often. Only matters in very good days of course and if I could have had south, I would have. I blame the idiot that built the workshop the panels are going on!

sponev

Once you get it installed, email me via support,

I suspect the 'fix' to Gen 2 is applying the work they have done so far to Gen 1 beta. I suspect that it wont be properly fixed but I may turn out to be wrong.

The issue is tracker 1's changed in conditions will make tracker 2 react/stop/low produce. The current condition of the G1 beta is that it will go from say 3.2kw to 600w and then back to 3.2kw when the other string has some more shading. Its worsened by the Tigo's constantly changing the voltage and thus the inverter trying to react accordingly.

Current condition is this is now very fast and I have gone way up in production from the fixes. The current release Gen 2 has all the hallmarks of late December beta Gen 1.

I have asked for some additional changes to be made in order to actually, and completely, fix the issue. Once I have the new FW loaded I will know as the current version that was put on my inverter a few days ago has gone back to stopping the other string when under MPPT (135v)

I can fix it by joining strings but this takes me to 560_Voc which is not ideal

joshgreenuk We're due to have a gen 1 switched to gen 2 next week so need to understand the issue before we do please. We have 10kwp split equally E/W and other than the dump/jump SoC issue, the system is doing as expected. We are not on the beta yet but have offered our system after the retrofit.

Am I right in thinking gen 2 non-beta has the E/W issue or just the beta? Also is it Tigo just exacerbating the issue please, or causing it?

Just need to check one last time before we install something which may take us backwards. Many thanks.

joshgreenuk , are the power fluctuations visible on the GE power graph with 5 minute data intervals, or are you using another App to monitor the data more frequently?

All I can tell from my GE power graph is that the inverter appears to need both strings above around 150 V in order start generating significant power.

So is this scenario made worse by having low panel count on 1 or both strings.
I have string 1 of 10 x 410 W (West), and string 2 of 6 x 410 W (East), but they are REC Alpha Pure panels that do have a high voltage/low current output in comparison with other 410 W panels. Voc (STC) = 49.0 Volts, Voc (NMOT) = 46.2 Volts.

Simon_C Those would easily hit the Voc wake up level, which is going to be reduced to 120v accross the fleet

TheDragon (GivEnergy) , has there been any progress on this for the Gen2 hybrids?

I have had a few mornings now with 100% light cloud cover with reasonable brightness, but the inverter does not seem to start up for over 1 hour around 0700 to 0800.
The power chart does not capture very much due to the instantaneous readings taken once every 5 minutes, but the App in Home mode shows a repeated cycle of generated power increasing from around 6 W to say 60, 70 or 80 W, staying there for 20 or 30 seconds, then dropping away to 6 W for another 20 or 30 seconds, then repeat over and over. The string voltage is certainly present, but no significant power output.

So is there an inverter firmware being beta tested just for this specific issue, or is it all encompassing with the battery %SoC issue as well so the inverter and battery firmwares need to be a matched pair to some extent?

I just feel I am missing out on quite a chunk of potential generation with the HY5-Gen2 as it is.

With beta firmware, this was the startup this morning, that looks like the 2 strings are separated and the East string ramps up quickly much earlier than the West string.

D0.996.A0.908 - 4074 battery

String 2 = 6 x 410 W (East -88deg).
String 1 = 10 x 410 W (West +92deg).

Just now have a different issue with timed AC charge control strategy with this beta firmware.

Simon_C Good to know, thanks for the update. We're also watching the other issue you mentioned closely. Bit nervous as we are scheduled to have a gen 2 retrofitted tomorrow (E/W) and don't want to be stepping backwards.

sponev.

I expect your Gen2 will have the factory firmware in it, so it then becomes your choice whether you stick with it and suffer reduced generation from the East/West strings and potential battery %SoC drops/rises, or you request to have the beta firmware loaded in both the inverter and battery which is somewhat unproven and get a new problem with the timed AC charge control strategy.

I am still thinking about the best workaround for the timed AC charge.
My issue is having to set the start and finish times to match the full cheap rate period only when I need to charge the car, otherwise it can be much shorter just as a backup to ensure I have at least say 50% SoC to cover household load through a dull day.
It is not a very useful automation when I have to remember to change the timings each day, whereas the previous strategy was almost a set and forget to match the cheap rate timings, then just remember the seasonal changes to the target %SoC.

Simon_C Thanks for this. I've agreed with Paul to get the beta firmware loaded as soon as the gen 2 is in and running. We have 19kwh of batteries and 2 x ASHP going in soon, so the array performance is important for us. We have over 10kwp split E/W and generation has been excellent - so a downgrade to this isn't an option really.

We manage timed charge a bit differently and rather manually. We tend to look at the following days weather and adjust the end SoC % and charge period accordingly. It's been quite predictable and normally we get very close. The only slight complication is when we need to charge the car, but working from home means we can handle most of it via the Zappi and solar. We still need the AC charge functionality to match the gen 1 however.

sponev We still need the AC charge functionality to match the gen 1 however.

I fully agree. It just seems strange to be removing a feature with a firmware update rather than enhancing the features.

I have this exact same issue with my E/W split. Inverter FW updated by GE this afternoon to D0.996-A0.908 - will this resolve the morning startup issue?

BarnabyDunning Yes,

Hope they also loaded BMS 4073 too
As its not managed by me running the beta trials, I cant see your system, unless someone makes me aware. we have 10s of 1000s of systems. So cant check all is done as i do it

Not sure if this is related or a different issue. I have two strings - string 1 is 9 x 405w panels south facing and string 2 is 3 x 405w panels east and 3 x 405w panels west with Tigo optimisers. 5Kw Gen 2, Image below from last full sun day when on the beta firmware D0.908-A0.908 but issue has been there since install and still seems present on D0.996-A0.908 albeit weather has been so variable I don't have such a clear example.

String 1 performs pretty much as expected but the performance of string 2 is disappointing - essentially I only get decent output in the middle of the day when the sun is overhead. Either side of that, I only see a couple of hundred watts output. On a full sun day shouldn't I be getting closer to 1000+w on string 2 much of the morning and afternoon with a bit more in the middle of the day when the sun is overhead?

Dw Just wondering if three panels is enough (i.e. one half of your string 2 in sunlight) to exceed the minimum voltage for the inverter? May be worth posting the same graph with the two string voltages as well (assuming you have a hybrid system and can see these).

Dw, at each end of the solar gen day your East and West panels may not be generating sufficient Voltage to properly drive the inverter string input given that you only have 3 panels on each face.

Do you have any monitoring of the Tigo optimisers that may provide more clues, or are you reliant on the installer for this?

Dw I've looked over a good few days of data, string 2 is for sure the weaker of the 2, luckily for you the new FW reduced the fire up voltage to 130v, else 3 panels would be not working at all. Your average voltage is around 160v in good light.
3 panels is right on the limit, even with the lower voltages

Simon_C It looks like I hit the startup voltage but then as soon as power starts flowing the voltage drops down a bit so its only just above the startup voltage. Image with string voltage added below.

I don't have any monitoring of the Tigo optimisers, was wondering if they were doing their job properly. @joshgreenuk, are you by any chance the Josh Green from Jem? If so, is there some monitoring for the Tigos that you can look at to see what's going on? (If not, sorry for tagging you)

TheDragon (GivEnergy). Thanks for looking at the data - as you say, it is good that the startup voltage has been lowered. The original system design had the panels split differently between the strings so string 1 would have been half the south facing panels and the 3 east facing panels and string 2 would have been the other half of the south facing panels and the 3 west facing panels. The guys who turned up and did the install changed this to south on string 1 and east/west on string 2. I have been wondering ever since whether performance would have been better if the install had followed the original design. Any thoughts on this?

Apologies all if I've inadvertently hijacked this thread and I have an install issue rather than an MPPT tracker issue.

It’s looking like an improvement then and DW issues are because really it shouldn’t be east and west on a single string.

Have you got space to add a panel on east/west sides or maybe just split it east/half of south and west/other half of south? East/west on the same string sounds a bit painful to me.

Probably looking 9 + 9 or 10 + 8 for the east/west with E on one string and W on the other.

kram thanks. I can’t fit more panels on the east/west so I’ll go back to the installer about the string config

Dw It looks as if the E/W string can't really provide enough power until 11:30 through to 15:45. My thought would be that East should pick up much sooner and west would decay later, in other words following the ramp up/down of the south panels to the 1200W peak. It looks as if the original spec with the south panels in a 50/50 split with E/W might have taken this into account?
I would suggest asking TIGO for their recommendation for your type of install. It might also be worth having a play with one of the configuration tools to check which is the best spit on the south panels to make sure the odd panel is put with the best direction.