I've just had a 10 x 410W set of panels installed and as its mid June and clear blue skies here (north Wales) I wanted to confirm that the peak output I'm seeing from the panels was correct. At it's peak the output is steady around 2.7-2.8kW,
Chris-Riley If it's south facing and no shade, sounds low. When mine were first installed, the shade from the scaffolding that was still up for the first week made a big difference (shade on one panels affects all the panels if you don't have micro inverters).
I have 8 x 410W panels, and I'm dead south facing and have seen 3.4 kW from them which is incredible considering it's max should be 3.28 kW.
There’s clear blue skies and clear blue skies. It’s surprising the affect a bit of haze can have.
The other thing I find is the temperature sensitivity. The output reduces on warm/hot days, so for example on clear sky days in April you get a higher peak output than a similar clear sky day in July because the air temperature is lower and the cells run more efficiently.
Roof faces south west and zero shade, scaffolding has gone, ambient is around 20C. I've asked the installer to check it but wanted to know if my expectations were unrealistic!. Yesterday it was constant (ie flat profile) at 2.7-2.8 kW from 12pm till 6pm. Is it limiting in some way I would have expected it to rise steadily to the peak and then drop of steadily. 
I'm presuming you're on a 3.6kW inverter, and at a guess are all your panels on 1 string? There is a bug in the release firmware which limits the power generation on a single string to half the inverter total. In the case of a 3.6 the DC max is I think 5500W which would tally with what you are seeing as half that is 2750. Assuming you're not hitting the current limit of 11A or 13A (Gen1/Gen2)
Phil_H
Yes it's a 3.6 kW inverter Gen 2 with panels on 1 string. Before it was commissioned I remembered seeing on our smart meter display it exporting up to 3.4 kW. Then on commissioning last week they did a firmware update. So what you say makes sense.
You probably have 2 options then, either leave it and wait for the FW to make it onto the portal for general update, or contact support and explain your problem, they have the FW and can apply it for you.
Chris-Riley Out of interest why did the installer put all of the panels on a single string?
MKICampaign Unless it's because you have definite plans to add another string this seems a bit daft. No redundancy - if one panel, joint, cable kills the string you get nothing.
I don't know, when we got the quote it was for 2 separate strings, but I only noticed they had installed them on one after they had left. Installation is in the loft so I didn't immediately notice.
Just to follow up on the issue, it now seems to be fixed and generating 3.7kW. Not sure how it was fixed, I let the installer know and they had contacted GivEnergy, so maybe they applied a fix.
I'm glad I noticed something wasn't quite right and thanks for the insight Phil_H
Think we have the same issue. How do you check it's on one or two strings?
HK in the portal on the graph you can remove what's on it and add pv power string 1 and pv power string 2. Then if its all one of of those strings the panels must all be on one string.
Phil_H thank you. String 2 is always 0w. Still haven't made final payment, so will flag this with installer as contract was for 2 strings.
I actually saw my solar power flatline for an hour and a half around solar noon (13:00 BST). I was worried that something was wrong, since the 3.5kW PV power was very close to the inverter's AC rating, but it was also charging the battery at 2.4kW at the time. As it happens, it was because one string was loosing power at the same time as the other one was gaining power around solar noon, when the insolation changes slowly as well.
Live and learn...
Positive for a single string in winter is you’re more likely to his the 150v startup voltage under poor conditions.
5 panels at 30v, which is normal for some, would barely start the string in pretty ideal conditions. 10 on a string will typically hit 250-400v.
As winter months set in, you might find periods where even in poor light you can push 150v and hit the inverter start up, so generating power when you wouldn’t otherwise do.
IMHO the wiring arrangement on a single string is correct and the firmware bug is what needs addressing.
I think I may have the same problem. I have a 3.6kw gen 1 inverter with 8x410w panels on a single string. Installed last October. When originally installed we had a temporary inverter which showed 3.2kW regularly. Since getting the GE inverter installed I have not seen above 2.7kW showing. Originally, I put it down to the winter but now we have full summer sunshine.
Is this likely to be the "bug" mentioned? Is there already a fix for this, or could I have a different issue? Not sure how to go about diagnosing. Any advice appreciated...
Not sure on mine now. I have 5.8kw east facing installed, so “peak” for us is about 11am ish. Max I saw today with a clear sky was about 4.2? I know temperature of panels can have an effect, but 1.6kw worth? They are a bit pollen coated though, but I have seen 5kw on a hazy day. So not sure what to make of it?
Chris-Riley your inverter got update to v909 yesterday. Solar looks better now. Single string unlock was one of the things in 909
ProximusAl Hi I’ve 10 x 385 w ( in two strings) on panels with a low angle 10 degrees but south facing. Have seen 3.4kw max so far with 22kwh on the best day. Just bought a Sunamp to soak up some of the spare electricity rather than support the National Grid. Saving up for an EV …
5kW of panels east or west at 35 degrees will generate about 80% of the power they would if south.
5.8 kWp (STC) producing 4.2kW is pretty good.
80% is 4.6% for being east and no panel I know of produce the STC values except under perfect conditions. 72% of nameplate value on an east array is pretty good in my book.
kram That's about right. We have 10.2kwp on an equal E/W split. Max we see is around 8.2kwp as the sun comes over the top, although there may be some inverter limitation involved. It aligns pretty accurately with the various solar forecast websites. At the moment we're regularly doing in excess of 50kwh per day and exploiting the handy Flux tariff.
You can also look at PV Data on the inverter tab in the portal. Mine shows Voltage, Amps and Watts information for PV1 & PV2. If it was on one string their would be no data on either PV1 or PV2. This avoids you having to edit the graph.
TheDragon (GivEnergy) will this update be released to the public? Or when?
rio911 yes
Could I ask what you string configurations are and what you see in terms of voltages/current and power.
We’re going for an equally split E/W 7.5kWp array, originally sma/Powerwall , but after let down then GE gen2, but supposed to be libbi now. However unanswered questions on string voltages/power means it could go to GE inverter(s) and AIO.
kram We have 12 Jinko 420w (might be 430w) on each elevation, pretty much E/W within a few degrees. This is handled by one 5kw gen 2 hybrid feeding two 9.5 batteries.
One a good solar day we see at least 4kw from each side and I've seen the overall peak around 8.2kw when the sun is high and directly overhead. We do get clipping however and I will set lower battery charge rates to minimise this when I remember!
Today we produced 52 kWh with some clipping, I guess max potential would be over 60kwh.
I don't have the V max for the panels to hand but apparently this is the limiting factor for how many you can use. I checked this for the Jinko panels we have (Tiger type I believe) and 12 per string was about the max per string with the gen 2, leaving a small margin. All has been fine so far, loads of excess for export and even on poor solar days in winter, we were still covering 50-60% of the house load.
If you need any data direct from the portal just let me know.
kram I have six 395w JA panels rather than five on two strings in my setup. The JA panels are 30v per panel but with a max output of around 12.8A (near the G2 inverter limit). I’ve taken a capture from the portal showing string 1 voltage, current and power on the worst day we’ve had for PV generation recently. Voltage is the line.
The panels ramp up to operating voltage before any significant power is produced. May be panel voltage characteristics was an issue in the past or may be it is with some other panel types but for my JA panels which run at a low voltage per panel, I see current vary rather than voltage.
kram Further to my post above, I just scrolled through the string currents over the last few high solar days and I see a max of 13A, so just at the limit of the gen 2. The Jinko data sheet suggest max current of 13.1A so it looks like I'm on the limit. No operational issues though. I also checked the config with GE support and they said all would be fine, excess power is dissipated via the panels and that it's the string voltage which is the key factor. Hope so!
It'll be fine. I can pin my Gen1 at 11A for hours if I need to, just means you get clipping. It's overvoltage they don't like (which your most at risk of on very sunny but very cold days)
We will have either 9/9 or 10/8 Trina vertex s 415w all black panels. Annoyingly myenergi changed the data sheet so a few of us are checking to see if it’s still ok.
Max recommended DC is only 6.5kW so I have this nasty feeling the answer might be no.
Max voltage is I think 560V, with 400v nominal 18A short, 15A max, with a max sustained of 2x13A if you look at the kstar product it’s based on.
Looking at the panels it seems it should be in there but no straight answers…
https://midsummerwholesale.co.uk/pdfs/dt-m-0035-a-datasheet-vertexs-de09r.05-en-2022-a-print.pdf
42V and 10A MPPT is well in.
50V OC and 10.6A SC should be ok too.
As such trying to get it in writing from the vendor as I don’t fancy picking up that bill.
The production figure are impressive and that 8kW+ around noon is stunning 👍
kram my folks have had the same issue as they are having an all ME system installed shortly. They were going to have a 10/8 south/west split with jinko 420W panels, but they’ve now swapped to a 8/8 split with eurener 400W on each string. So 3.2kw/string, giving 6.4 max.
kram I'm no expert but I did some preliminary reading up before we went ahead. I also checked with the supplier (now defunct) and importantly GE to gain further reassurance. I'd push it back to the installer to sign off and then sense check it yourself. It can be tricky when the specs keep changing though!
Record day today I think. 64kwh and 44 exported. The batteries are still at 65% so I'll need to create a bit more space tomorrow to delay the clipping. The car is charged so nowhere else to put it, not grumbling as Flux is mopping it all up nicely.
Waiting to hear back but will change to a solaredge or suitable string inverter and batteries rather than take a hit on generation. Being east west we are oversizing for winter.
Absolutely, I have put it in the hands of the installer and asked them to get confirmation it is an approved system from ME in writing.
Those export and generation figures you are showing are fantastic. Our plan is load, battery, car, possibly hot water and export.
How does flux work out for you with the EV?
kram
I gave up a while ago with the Libbi as the specs seem to just move around on a whim (not that GE ones have been particularly shining in this aspect but the key ones have generally been right)
On paper that looks a bit on the knuckle voltage wise to me (a bit of a buffer ideally) but I rarely comment on here things like that (there's enough armchair elec. engineers on here, strangely not so many when you want to employ some!)
I've got 6.1kW of panels & 2.5kW of PV String battery stuffed on my Gen1 5.0 (so 8.6kW total) full south facing and because the voltage is well within limits all it does is clip if it get's too busy.
kram We are irregular drivers these days so still plenty for the car and for export. We are having ASHP soon so will switch tariffs accordingly as we approach winter.
Just out of interest which bit do you think is close?
I ask as even 10x50V short circuit voltage is 500v so under limits. I mean I am of course assuming the short circuit is a fault and not the bypass diodes all working.
9 and 9 would of course be far safer because then it’s 450v
So far no answer from MyEnergi, so I guess we will see tomorrow. Wotg the premium price I’d rather pay the same if not less for an SE solution that will work if libbi can’t answer.
Potentially could consider a solar edge + 48v batteries or solaredge inverter + the GE AIO and gateway.
Shall see what comes from it.
kram, the 50.0 Voc for the 415 W model is under STC conditions which is 25 degC.
The data sheet indicates the temperature coefficient of Voc to be -0.25%/degC, so at say -5.0 degC the Voc will be 7.5% higher than the STC value of 50.0 V (10 * 50.0 * 1.075 = 537.5 V). I seem to remember the rule of thumb used by installers is to allow 25% headroom on the STC value up to the inverter maximum voltage.
Thought I was missing something.
MyEnergi came back and said any more that 3.25kWp per string voids the warranty .
Frankly that’s rubbish as we go down from 9x to 7x per side or losing 830Wp at STC or 630 at NMOC.
For a “premium” priced product it’s pretty shite to have such a low limit.
kram,
With my East/West roof layout which has a 30deg slope angle, PVGIS5 indicated a peak clear sky irradiance of just above 900 W/m2 at 10:00 on the East and 14:00 on the West (presumably GMT times, so add 1 hour for BST).
This 900 W/m2 is mid-point between the NMOT and STC performance conditions.
Not sure though if any installers or manufacturers take the East/West split in to account when approaching the limits of the inverter capability. In my opinion they should do, as it is not like you are able to rotate your roof so all the panels face South after the installation has been finished.
Wishing I had a couple more panels up on the roof for Winter performance, but at the time the GE HY5 Gen2 data-sheet did not allow any more. It is frustrating that the GE data-sheets seem to be a moving target, and some limits change with a firmware update.
Another person affected by the libbi issue has been told maybe we need to speak to kstar.
I mean seriously.
Will see if 8x405 at 3240kWp is a viable alternative
Out of interest what do you have east/west in terms of panels and generation capacity on each side?
kram,
All REC Alpha Pure 410 Watts, located in the East Midlands.
West = 10 panels, East = 6 panels, so get more generation in the afternoon/evening when I am most likely home for EV charging and expected higher consumption for cooking.
16 x 410 W if all South facing = 6560 W, the data-sheet limit at the time of system design and install.
Actual peak on clear blue sky day such as 2/6/2023 is 4531 Watts at 13:40 with a 5000 Watt rated inverter. West string peak power = 3284 W at 15:45 on the same day.
On days with sunny spells between clouds I have seen peaks of around 5500 W, but they only last for 5 to 10 minutes, and are caused by the direct sunlight and reflections from the clouds combining.
Yesterday produced a near perfect generation curve shape (PB of 40.2 kWh), but somewhat reduced peak output due to the air temperature affecting the panels as expected.
Thanks, sadly the myenergi person my installer spoke to have said max 3250kWp per string end of story or warranty void.
Unless that is changed I see 3 options:
1) stay with libbi.
drop to 16x405kWp panels
Up to 3 batteries 13.8kWh usable
2) stay with 18 x 415/420kWp panels
Use GE g3 5kW and 9.5 battery
Chance I get SoC drops and may have to write off inverter/battery in time.
3.6 max output is lower than the 5 for other options.
3) stay with 18 x 415/420kWp panels.
Get GE/SE inverter and AIO + gateway
Will need to revisit DNO as two inverters.
18 x 415 generates Approx 6800 kWh / year
16 x 405 generates Approx 5800 kWh / year
14 x 420 generates Approx 5250 kWh / year
Thoughts appreciated
kram I’d probably go AIO. I would have done so
Myself if it had been out when I orders my system.
6kw discharge, whole house backup with the same discharge rate and panels still work on top off that, plus reasonable integration to ME products.
I don’t think GE do their own PV inverter to you’d need a third party like solar edge or solis
Was thinking of just slapping a GE hybrid in there with no battery. I assume it’ll work.
The libbi can do 5kW backup and will charge the batteries off grid.
It’s a cost calculation I guess as I don’t want to throw away part generation potential but if AIO + SE was more expensive it’d be painful.
Would you consider a GE hybrid if it was say £3-4K cheaper than the other options?
Random q… how much “export” do you have available on the 6.5kWp on a good may-July month?
I always wanted AC coupled as it integrated better to my Zappi/Eddi plus higher power if required as I get contributions from both battery and solar. If I went hybrid I would be limited by the inverter. AIO is actually highest output of all as it’s like this. So you’d have 6kw from battery, plus whatever from solar (if available during the day)
I have an east facing setup and it’s my first year with it so not sure what I’ll manage over the year. In May I generated 632kwh and exported 98 from a 5.8kw array.
You make a good point about battery plus inverter output.
I guess my real choices are either:
Libbi and take the hit on generation, the larger battery should help in winter/peak
SE and AIO
kram on your point on price, it’s almost a non brainier
Libbi 5kw inverter plus 15kw storage is £12412.40 on midsummer (13.8kwh usable). Only 2 circuits can be backed up on power cuts
AIO plus gateway £6993 13.5kwh usable plus full house backup.
True you have to get a separate pV inverter but that’s not going to be £5k worth!
Exactly my current thought process too.
So libbi got dropped, because they won’t allow over provisioning for arrays in opposing directions?
My install has been told if it was done it’s without warranty.
I’ve 10 x 390w panels facing due South in the Scottish Borders have seen a peak of 3.68kw and am seeing a daily total, regularly of 22kwh.
The panels are only at 10 degrees slope. The frequent showers between sunny days is cleaning the panels and keeping the air clear?