Power Output vs Rated Capacity
I've 14 x 395W solar panels with an array peak output of around 5.5kW. The panels are ground mounted at around 31° pitch, exactly south facing and were installed only last September. For the past week or so we've enjoyed clear blue skies with the sun about as high as it gets. PV output has generally been 30kWh a day or greater BUT the peak output is nowhere near the rated capacity and tends to flat line consistently at 4.1kW, see attached yellow line in screenshot.
I realise there will be system losses between panels and the inverter, and also that power output diminishes with temperature of panels (coefficient is -0.35% per °C) but a peak output of 4.1kW is only just over 70% of rated capacity and, intuitively, seems low.
All may well be fine, but I've no yardstick. I'd be interested to learn what others are experiencing.
2 x 12kW Samsung Gen6 ASHP, 5.6kW solar PV ground mounted c/w 10kWh Puredrive battery & Solis inverter.
it could be clipping- what size is your Solis inverter?
4.4kW PV with 9.5kWh Givenergy battery. 9kW Panasonic Aquarea L ASHP
3.6kW. I've 10kWh worth of batteries in the system as well, although they are currently not working (hardly accepting any charge) and are due to be replaced tomorrow under warranty. Don't know whether that is pertinent to PV yield.
System output has been higher before, 4.8kW output not uncommon and, since first installed, a peak of 5.2kW. It's the straight line output that makes me take notice.
2 x 12kW Samsung Gen6 ASHP, 5.6kW solar PV ground mounted c/w 10kWh Puredrive battery & Solis inverter.
It’s your inverter that is throttling your output. Your installer shouldn’t have proposed a 3.6kW inverter with a 5.5kW array (at least not without making it clear how much you could lose from clipping). They probably did it so they could stick with a g98 application and not have to apply for a g99 which would’ve allowed you to have something like a 5kW export limit. This limit means you can only use a max of 3.6kW of AC in the house/exported plus any excess will be sent as DC to your batteries (assuming they’ve worked to some degree since install).
The times when you’re seeing greater output from the panels is likely when you have spare battery capacity which absorbs any excess as DC that the inverter can’t take.
At this point you could either
1)put your own g99 in to get a 5kW export limit and pay for a new inverter
2) Make sure you have capacity in the battery when sun is forecast and set a slow battery charge rate (say 1.5kW) so that the battery slices the excess power off the top over a 4-5 hour window before it’s full.
4.4kW PV with 9.5kWh Givenergy battery. 9kW Panasonic Aquarea L ASHP
If it was a split E-W array or had shading then I could see a place for a 3.6kW but otherwise it’s laziness
4.4kW PV with 9.5kWh Givenergy battery. 9kW Panasonic Aquarea L ASHP
@dougmlancs Thanks, that's really helpful.
I did have a diicussion with the supplier early doors about inverter capacity. In the end, whilst I agree it seems daft to have a bottleneck like this, I thought it would have marginal impact overall and so left as is. I suspect it's more apparent now as the battery fault (whatever that is) is telling the system they are full when not.
As a side issue, it's all a bit academic as my smart meter doesn't work (come on Octopus! ) so I'm giving it away to the Grid. You're welcome. 😂
2 x 12kW Samsung Gen6 ASHP, 5.6kW solar PV ground mounted c/w 10kWh Puredrive battery & Solis inverter.
Posted by: @dunlornI've 14 x 395W solar panels with an array peak output of around 5.5kW. The panels are ground mounted at around 31° pitch, exactly south facing and were installed only last September. For the past week or so we've enjoyed clear blue skies with the sun about as high as it gets. PV output has generally been 30kWh a day or greater BUT the peak output is nowhere near the rated capacity and tends to flat line consistently at 4.1kW, see attached yellow line in screenshot.
I realise there will be system losses between panels and the inverter, and also that power output diminishes with temperature of panels (coefficient is -0.35% per °C) but a peak output of 4.1kW is only just over 70% of rated capacity and, intuitively, seems low.
All may well be fine, but I've no yardstick. I'd be interested to learn what others are experiencing.
Have you considered rearranging your panel array to have 7 panels facing South-East and 7 facing South-West, which may help spread solar production more evenly throughout the day?
It will be much better when your battery’s working. I feel your pain- I missed the whole of May’s potential Flux payments because of my DNO being slow. Once it starts rolling in you forget about that bit though!
4.4kW PV with 9.5kWh Givenergy battery. 9kW Panasonic Aquarea L ASHP
That's a good shout @derek-m, trouble is they are fixed on a timber frame and changing it now would be a helluva task. It never occurred to me to do that tbh, I just opted for pure south facing.
2 x 12kW Samsung Gen6 ASHP, 5.6kW solar PV ground mounted c/w 10kWh Puredrive battery & Solis inverter.
- 25 Forums
- 1,440 Topics
- 30.2 K Posts
- 21 Online
- 1,225 Members
Join Us!
Latest Posts
-
RE: Are Octopuses Slowing Consumer Adoption of Heat Pumps?
That's one of my main objections to Octopus wanting to ...
By IvanOpinion , 1 min ago
-
RE: EV charger installation question – I don't want to bury the cable
@transparent I found this on outer wall of garage..l...
By Hem , 54 mins ago
-
Relax with 4K drone footage of lawn mowing to a smooth Motown tune
Sending out some chilled weekend vibes to everyone. Lis...
By Mars , 3 hours ago
-
RE: Incorrect Billing of Customers with a Smart Meter
The starting point of that discussion on Camelot-Forum ...
By Transparent , 4 hours ago
-
Share Your Experiences with Heat Pump Manufacturer Support
Have you ever reached out to your air source heat pump ...
By Mars , 18 hours ago
-
RE: Is this a bad installation and is there something wrong with my Samsung heat pump?
@ant87 thanks for that.
By David999 , 1 day ago
-
RE: No-code, plug-and-play monitoring for your heat pump
But if you compare what was predicted with what happene...
By Majordennisbloodnok , 1 day ago
-
RE: Aira Heat Pump: Stylish Scandinavian Heating
I might change my mind again, but I'm currently unlikel...
By IvanOpinion , 1 day ago
-
RE: Samsung ASHP scheduling help
@elgreco69 worth reading the GitHub here as that will a...
By morh , 2 days ago
-
RE: ASHP sizing - value of Heat Transfer Coefficient
@toodles Thanks for the explanation I get it now as I h...
By Jancold , 2 days ago
-
RE: Questions about yearly heat pump maintenance
For the installer, I believe servicing and maintenance ...
By Majordennisbloodnok , 2 days ago
-
RE: Rate the quality of your heat pump design and installation
@retrorich It is very worrying that any of this should ...
By Toodles , 2 days ago
-
RE: Spacing for roof fixing bolts ?
There is another consideration...but alas this doesn't ...
By Transparent , 2 days ago
-
RE: Air source heat pumps and noise
Yes, but when they go wrong things get really sticky. D...
By Majordennisbloodnok , 2 days ago
-
RE: Noise problems with newly installed Samsung 8kW ASHP
Hi, Bit of an update. I bought a decibel meter and moni...
By Lokisam , 2 days ago
-
RE: Are You Getting the Most Out of Your Renewable Energy?
As I mentioned, there are going to be some follow-up ar...
By Majordennisbloodnok , 2 days ago
-
RE: Tell us about your Solar (PV) setup
Now, I know that this may be a little simplistic and pe...
By Toodles , 3 days ago
-
-
RE: Save the Energy Save the World using Daikin Altherma 3 operation mode and schedules settings.
Hello Mevl, I won't be able to answer all your question...
By HCas , 3 days ago
-
I have been watching, with interest, the rebuild and re...
By iantelescope , 4 days ago
Heat Pump Humour
Latest Topics
-
Share Your Experiences with Heat Pump Manufacturer Support
By Mars 18 hours ago
-
Spacing for roof fixing bolts ?
By heat-pump-newbie 5 days ago
-
ASHP sizing - value of Heat Transfer Coefficient
By jamesw 5 days ago
-
Incorrect Billing of Customers with a Smart Meter
By KoRWraith 1 week ago
-
Home energy storage & battery register
By Mars 1 week ago
-
Meter Readings - What are theses meters telling me?
By Potatoman 1 week ago