System limiting output - Growatt/Shinephone app settings?

[ConfusedKyle]

Hi Everyone,

I got a 6.5kw battery and Hybrid inverter (Growatt) installed alongside a 4.9kw Canadian Solar panel system in March or so this year.

So far the system has worked well, but one days where we have unbroken sunshine - like today, it seems to limit output?

Today for example it's full sun at home where my wife is, I have the dashboard open on my computer at work and our production high is 2.68kw. The battery is full, house consumption is minimal (0.23kw, pretty much normal) and we are exporting but only at 2.4kw when we could be exporting a whole lot more.

We've had no trouble hitting 4.9 on days where it's less sunny but theres a break in the cloud, it bizarely read 5.8 at one point a couple of weeks ago.

It's also annoying because we have just switched to Octopus Flux and want to take advantage of the good weather.

Please feel free to patronise me, I find the app very confusing and I'm terrified I'll change a setting and shut the whole thing down!

Cheers, Kyle

 

[johnb2713]

What settings are in the inverter for export, specificall export limit, on or off & what % ?

What model of inverter do you have?

 

[ConfusedKyle]

No export limit set, model is SPH3600

 

[Si_Oakwood]

Hi, what mode is the inverter in? If it's "load first" then this sounds about right to me. Battery at 100%, load 0.23k, solar 2.68kw, leaves 2.45kw excess PV to export.

 

[ConfusedKyle]

Thanks for the reply - I can't see from the setting what mode it's actually in. I think it is load first though.

Does the "lack" of production ring any alarm bells though?

It's full sun at the moment and has been for most of the day but we've barely gone above half the capacity of the panels?

 

[Si_Oakwood]

Thanks for the reply - I can't see from the setting what mode it's actually in. I think it is load first though.

Does the "lack" of production ring any alarm bells though?

It's full sun at the moment and has been for most of the day but we've barely gone above half the capacity of the panels?

it does yes, it seems low for a sunny day. do you use the shine server (https://server.growatt.com/)? if not, this provides more information than the shine app such as the mode, and it's easier to export stuff. would be interesting to see the total energy chart for the day. you can also get at more settings in there.

 

[ConfusedKyle]

it does yes, it seems low for a sunny day. do you use the shine server (https://server.growatt.com/)? if not, this provides more information than the shine app such as the mode, and it's easier to export stuff. would be interesting to see the total energy chart for the day. you can also get at more settings in there.

Yes I have it up during the day on my computer at work. I've got "On-Grid mode" as the system state at the moment.

 

[binky]

,
Check the panels are clean and haven't got a thin layer of dust on them.

Check there isn't a thin layer of high cloud.

If the app shows it, it may also be worth checking the internal inverter temperature. At around 70C they shut down a bit to protect themselves. Mine is currentlyat 51C in my garage.

 

[ConfusedKyle]

,
Check the panels are clean and haven't got a thin layer of dust on them.

Check there isn't a thin layer of high cloud.

If the app shows it, it may also be worth checking the internal inverter temperature. At around 70C they shut down a bit to protect themselves. Mine is currentlyat 51C in my garage.

Thanks, doesn't show the temp on the app but the system is set up in the attic which is typically hotter or colder than the rest of the house. However its also been the case on sunny days where the temperature has been cooler.

 

[binky]

No export limit set, model is SPH3600

so the limiting factor is the inverter, it's designed to run at 3.6kW and you have nearly 5kW of panels attached to it, you won't hit 4.9kw except as an odd spike. I suspect what is happening is that the inverter is making itself less efficient to cope with high output from the panels, effectively cutting output. The upside of having a set of panels larger than the inverter is improved winter output, but personally, I gave up undersizing inverters years ago. Undersizing is taught as acceptable practice on solar design courses, but they are a little out of date as inverter efficieny has vastly improved over the last decade

 

[ConfusedKyle]

so the limiting factor is the inverter, it's designed to run at 3.6kW and you have nearly 5kW of panels attached to it, you won't hit 4.9kw except as an odd spike. I suspect what is happening is that the inverter is making itself less efficient to cope with high output from the panels, effectively cutting output. The upside of having a set of panels larger than the inverter is improved winter output, but personally, I gave up undersizing inverters years ago. Undersizing is taught as acceptable practice on solar design courses, but they are a little out of date as inverter efficieny has vastly improved over the last decade

Riiiiight so its the inverter.

So essentially we will be limited in the summer but be more efficient over the winter.

Which implies we need to use the battery more to utilise the higher prices for the export tarriff.

Thanks for the help, this has been annoying me for weeks.

Is that 3.6 kw hours? Because the system CAN hit the 4.9 mark but just not consistently on sunny days.

 

[Si_Oakwood]

I also have an SPH3600 and this was yesterdays output (capped at 3.6kwh as expected):

 

[binky]

Riiiiight so its the inverter.

So essentially we will be limited in the summer but be more efficient over the winter.

Which implies we need to use the battery more to utilise the higher prices for the export tarriff.

Thanks for the help, this has been annoying me for weeks.

Is that 3.6 kw hours? Because the system CAN hit the 4.9 mark but just not consistently on sunny days.

No 3.6kw or 16amps. I'm not sure if it limits what's going into the battery, but the 3.6 comes from limitations on back feeding the grid in compliance with G98. I would still expect it to run at 3.6kw for at least part of the day though. So perhaps there's something else going on. !Might be worth googling if the inverter can be reprogrammed as I believe its a software limited 4kw inverter.

 

[ConfusedKyle]

Hi Everyone,

Thanks for your input. Spoke to the installers yesterday who have some sort of master-data version of Shinephone who said their numbers and mine were reading differently. Also looked at the Octopus tariff information, their info says we exported 26kw on friday, but both Shinephone and Growatt server say we only produced 20kw, and exported 13.

Something definitely isn't adding up, so they're coming out on friday to have a check over of the system - they mentioned striking on the phone, can anyone define that for me? All I get on google is lightening strikes.

The way my system is distributed is I have 4 400w panels on a south facing roof and 8 on a west facing roof - I wanted 5/7 but the roofers made an arse of it.

They've that 4 panels on one string have been causing issues, I just wondered if anyone could speculate as to what these issues might be?

 

[ConfusedKyle]

No 3.6kw or 16amps. I'm not sure if it limits what's going into the battery, but the 3.6 comes from limitations on back feeding the grid in compliance with G98. I would still expect it to run at 3.6kw for at least part of the day though. So perhaps there's something else going on. !Might be worth googling if the inverter can be reprogrammed as I believe its a software limited 4kw inverter.

Thanks binky, I'll have a look at that today as well.

 

[ConfusedKyle]

Hi All,

Thanks again for the input, greatly appreciated.

My installers have been our and said that the 4 panel grouping is not generating enough Voltage to kick in, hence the seemingly throttled performance of the system. Apparantly Growatt altered the voltage required for their inverter without telling anyone so they didn't check the spec.

Long story short, they're replacing my single inverter for an AC coupled Solis and a DC Growatt free of charge.

Still nothing re the Shinephone app though, which is a confusing one. There are technicians in the UK who are using whatsapp, DM me if you need a number.