





Clockman commented on.looking to achieve a 1kWh output even in the poorest of conditions which as an idea fairly cuts through the Gordian knot and makes good sense. This is my wee bit of that although just in cloudy conditions, not full on Winter.

As you posted I was (of course).checking again and the sun was trying to break through (didn't make it) but it was enough that we had 4.8+kW coming in. In real terms, the washing machine has been on twice, HWT for two hours, dishwasher is going on and the SOC is still climbing slowlyOldgreybeard wrote: ↑Tue Aug 23, 2022 1:16 pm If I could generate around 10kWh or so on cloudy days then we could pretty much run off-grid all the time, so the 1kW on cloudy days seems a pretty good target. Our 6kWP system struggles to generate more than around 300W to 400W on days like earlier today, when we had pretty heavy cloud cover. Just roughly doubling that would be enough to run the house and put back enough charge to keep us going until the following day. With the price of panels looking reasonable when compared to the cost of electricity it's looking to make more and more sense to add more of them. Need to pull my finger out and see what I can do to extend our system.
Solaredge 12.1kWhmarshman wrote: ↑Tue Aug 23, 2022 4:00 pm Last wednesday afternoon when we finally got a few mm of rain we had thick black cloud and around 2:30 I had zero generation from over 10kW of PV. This lasted from around 2:30pm to 4:30pm. I first noticed it on my old legacy 3.15kW system, the SB3000 inverter was sat there with a flashing green light, then checked the new system and it just said 0W. At first I thought there was an issue with the grid but it was "situation normal", just not enough out put from the PV as it was so cloudy. I am on the south coast and all my main PV is at a shallow 11 deg angle. So even in summer on the south coast you can get periods where there will be absolutely zero generation.
I am waiting for the dark days of December and January to see how we fair - If there are more than a few prolonged day time periods of zero generation than no amount of extra panels will help, but if most days there are few hundred watts means extra panels will help. I have space to put them up and was considering having another 6kW of extra "winter only" array which I could switch in when conditions are poor to boost generation. Then there would be no need for extra inverters or getting the DNO involved.
In the deep south - Dorset. Managed to generate a bit over 18kWh today, but next to bugger all this morning, we were struggling to generate as much as 300W to 400W until just before lunch. Brightened up this afternoon, though. Started the day with the battery at around 52%, now it's 67%, but the dishwasher's been on, the washing machine's been on, the aircon has been on all day and the hot water took around 4kWh, so a net gain on yesterday, banked in the battery for tomorrow. Might get to top the car up on Thursday, if the forecast turns out to be right.Joeboy wrote: ↑Tue Aug 23, 2022 3:46 pm Not sure where you are in the country OGB, I am in Inverurie, Aberdeenshire.The weather today has been very hit or miss. Mostly cloudy will a few spats of rain and a couple of hours of intermittent sunshine. A few years back I'd have been grid grabbing by now!
The day started with an soc of 27% in the 14.4kWh stack, since then..
HWT charged
2 x washing machine runs at 60 degs
1 dishwasher cycle
1 hour tumbledryer![]()
Air fryer cooked lunch
Kettle has been on about 5 times
Charged a couple of handtool batteries
Chucked 1kWh at the EV to show off![]()
15.30 and SOC is 60%![]()
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An average to poor Scottish Summer weather day, yet all business is taken care of and we will finish better than we started. It is surprising how quickly it becomes a cornucopia of power once the basics are taken care of? I will post the split later this evening. The Victron system used to lag behind the Solaredge by an average of 21% by days end.
Sorry!marshman wrote: ↑Tue Aug 23, 2022 8:14 pmI was really responding to OGB's musing about adding more for generation on cloudy days. As you say adding more PV will extend you further into those shoulder months. I think you are correct dec to feb up in the far north is very difficult with PV. I will most likely see how this winter goes with the current set up which will give me enough data to know if I can justify the cost of another 6kW of panels - pretty much everything I have ever done RE wise has been done with an eye on the economics. I looked this afternoon and the cost of second hand PV has roughly doubled since I bought 5.7kW worth (20 285W panels) in summer 2021.Joeboy wrote: ↑Tue Aug 23, 2022 6:28 pm
Marshman, I've just wanted to strip a couple of weeks off the shoulder months and absolutely kill it in the good months!Nothing to be done about Dec to Feb though up here. Thats when the low energy gear in the house comes into its own.I think you'll do well with 6kW extra panels, are you tagging them back to batteries?
If I did go for it I would feed them into the hybrid inverter which has the battery stack attached, switching the current E-W arrays to a single MPPT by paralleling them and then adding the other 6kW to the other MPPT in 2 parallel strings facing south at a shallow angle. That should make the best of the available energy on overcast days when it is needed most.
I will also find out how long the battery stack will run for when the heatpump is running - may end up adding another 7kW to the stack - when prices stabilise!