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.
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.
Smart Tech Specialist with Octopus Energy Services (all views my own). 4.4kW PV with 9.5kWh Givenergy battery. 9kW Panasonic Aquarea L ASHP
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.
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.
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!
Smart Tech Specialist with Octopus Energy Services (all views my own). 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.
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