What are YOUR solar PV's generating TODAY?

jouster

Moderator
well on the 26th April PV production was on course for being our best month EVER since install with a 18.37 average daily generation....then the last 4 days happened and we've dropped down to 17.2 as a daily average for the month.

Still, the best April ever for us and in fact only bettered by May and Jul of 2018....

at the end of the day this never Invertor seems far more efficient than our previous one although its amazing to see how much the climibing temperature are efecitng performarnce levels of the panels.

rain seems to be over for a while now so lets see how May starts off
 

mikeysthoughts

Well-known Member
Up to 19KWh so far today. Interestingly the current output is about 10% down on previous peaks I've seen despite it being a bright, clear warm day.

How often do people get their panels cleaned? I don't think it's something the previous owners will have done in their 10 years of ownership
 

jouster

Moderator
i haven't cleaned my panels since they've been installed in November 2011 but on the odd drone inspection I give them now and then, they look to be pretty fine...and I'm sure my roof pitch helps when we get regular heavy rainfall.

Don't forget that panels lose productivity the hotter they get...

In fact a couple of weeks ago when we had the cooler spell of weather...I could see my panels were performing far better than they are now and that is just because of the beating sunshine on the panels. Being black they just suck up the heat....this is also why they still give good performance on cold winters day with bright sunshine for much less hours....panel actually work better when cool/cold
 

mikeysthoughts

Well-known Member
I haven't been able to find anything about the optimum temperature range for my panels but I suspect you're right.

We haven't had more than a few mm of rain in the last two months so that may be contributing.
 

jouster

Moderator
I haven't been able to find anything about the optimum temperature range for my panels but I suspect you're right.

We haven't had more than a few mm of rain in the last two months so that may be contributing.
I think your panels would need to be pretty dirty to have any real effect....being dusty isnt going to impact things as much as heat. If however they were covered in birds mess...that might affect things a bit more.

Again, the reason you are getting more generation a day at the moment isnt because of the weather as such...its because it gets brighter earlier and stays bright longer...but conversely the heat is negatively affecting your production as well

Quick google found this but there will be plenty of similar documents out there..hope this helps a little
 

mikeysthoughts

Well-known Member
Again, the reason you are getting more generation a day at the moment isnt because of the weather as such...its because it gets brighter earlier and stays bright longer...but conversely the heat is negatively affecting your production as well
Yes, thanks, I have a good appreciation of this....
 
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mikeysthoughts

Well-known Member
Partly the incident ray angle and partly the optimum operating temperature of the panels and equipment. I believe UK panels are optimal at around 15-19C air temp. In more southely latitudes they are built to have a higher optimum operating temperature, as you'd expect for warmer climates.
As shown here. :thumbsup:

It's obviously impossible to have a direct comparator but if anyone has had theirs cleaned, it would be good to know if you had any positive results.

10 years is a long time to not clean anything, especially if its outside and its only job is to absorb sunlight...

If rain cleaned everything, I'd never have to wash my little Suzuki!
 
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jouster

Moderator
whilst I have no real means of measurement...Im certainly seeing heat impact my PV...on cooer day (around 12-15 degrees) with full sunshine, Im seeing my peak output hit as high as 3.91KW...but in the last few days with temps above 20 degrees and even more at the panels...

The absolute peak I've seen in the warmer weather has been around 3.4..so its interesting to see how much the hot weather is having it is having

The great thing is longer brighter days means the total daily generation is maxing out around 23-24 KW still anyway so all good
 

mikeysthoughts

Well-known Member
It's a couple of degrees cooler than yesterday and I'm seeing output back up to 3.5KW , which reinforces the hypothesis that temperature is the main factor in the 10% drop from a couple of days ago.
 

gangzoom

Well-known Member
Regardless of efficiency the recent spell of hot weather + home battery storage + me cutting down on EV car millage has meant our grid electricity usage has gone nuts.

For this month we are heading towards 10kWh of grid electricity usage, which will translate to about £1, our standing charge will £6 so considerably more!!



We normally start the day with low charge on the home battery (today was 8%), and by usually by early afternoon the battery is full, any excess electricity is than sent to the boiler to heat the hot water. When I get home, the battery is than drained as I charge our EV using electric stored in the battery.



Today I noticed the PV system was exporting to the gird instead of heating up the water, however it turns out its because the hot water was already too hot!!!

So despite charging an EV which is currently doing about 15 miles a day, home electricity usage, heating the hot water, our small 4KW system is producing MORE electricity than we can consume!!



 

jouster

Moderator
Exactly how it should be I’m very interested in battery storage but until I get an EV it will be on hold I’ll only benefit I guess as battery systems come down in price and with my yearly generation doing well YoY a battery system will have paid for itself again in another few years
 

mikeysthoughts

Well-known Member
Regardless of efficiency the recent spell of hot weather + home battery storage + me cutting down on EV car millage has meant our grid electricity usage has gone nuts.

For this month we are heading towards 10kWh of grid electricity usage, which will translate to about £1, our standing charge will £6 so considerably more!!



We normally start the day with low charge on the home battery (today was 8%), and by usually by early afternoon the battery is full, any excess electricity is than sent to the boiler to heat the hot water. When I get home, the battery is than drained as I charge our EV using electric stored in the battery.



Today I noticed the PV system was exporting to the gird instead of heating up the water, however it turns out its because the hot water was already too hot!!!

So despite charging an EV which is currently doing about 15 miles a day, home electricity usage, heating the hot water, our small 4KW system is producing MORE electricity than we can consume!!



An enjoyable and useful read, thanks.

What is the peak energy consumption of your water heater, and what size is it? We have a gas one at the moment and I'm wondering if the economics of an electric one would work out.
 

gangzoom

Well-known Member
What is the peak energy consumption of your water heater, and what size is it? We have a gas one at the moment and I'm wondering if the economics of an electric one would work out.
Its got a 16amp fuse so cannot be more than 3KW, but I would stress the last few weeks have been very abnormal interns of solar PV generation for this time of year, but still.


This is my electricity bill for last 30 days. Yesterday at 5pm the PW was at 100%, the car at 90%, water heater was off again because the water was hot and I ended up exporting 4kWh to the grid!!

The other thing different is am using my pedal bike to cover most commutes/errands at work so my home EV car charging usage has dropped by over 50% compared to last year. I feel like am been ripped out by the energy companies, given am been charged more for standing charge than electricity usage :).



 

mikeysthoughts

Well-known Member
Is your export rate tracked accurately or assumed 50%?
 

gangzoom

Well-known Member
Is your export rate tracked accurately or assumed 50%?
Assumed 50%, which in reality is now more like 5% exported.

The PowerWall has really added a new dimension to our solar PV setup, once costs come down I think its a no brainer to have every solar PV setup connected to some kind of battery storage system, even if 20% of domestic solar PV sets ups was teamed to battery storage any worries about future grid balance/demand can be sorted without having to investment in massive centralised power generation........well in summer anyways :)

 

mikeysthoughts

Well-known Member
Agree. I'm looking forward to a drop in prices when the first wave of car batteries become available as home storage units.
 

jouster

Moderator
this was my best month ever since the PV install back in late 2011

The daily average for May was 18.58KW on my 4KW system

Sof ar for this qtr (apr/may.jun) iIm at £624
 

gangzoom

Well-known Member
Weather report for June is looking much better for the garden, not so much so for solar.

Will be interesting to see how our home 4KW + battery performs. I suspect it'll be OK still for home usage but EV charging will have to go back to grid power.
 

jouster

Moderator
Weather report for June is looking much better for the garden, not so much so for solar.

Will be interesting to see how our home 4KW + battery performs. I suspect it'll be OK still for home usage but EV charging will have to go back to grid power.
the wife will be happy as she won't have to water the vegetable patches every night for a few days at leasst.
 

gangzoom

Well-known Member
Ok I didn't expect to see this on my home battery status report after a few days of rain+cloud!!

Nearing 100% SOC and about to start exporting to the grid, and sun set is still a good 4 hrs+ away.





Weekend weather looks just as good as the last few days, but it appears despite the clouds/rain even just a little bit of sun peaking through for short periods is enough to power most of our domestic usage and keep us off grid :).

The EV is currently still sitting at 70% SOC as I don't drive it much anyways, so might make it another week before needing to draw much electricity from the grid, having a home battery system really does take solar PV on the next level :)
 

gangzoom

Well-known Member
Ok now its getting ridiculous, far from been worried about not having enough solar PV to keep the battery charged and run the house, the BMS on the battery has decided there is so much solar PV energy around in additional to exporting to the gird it'll start the immersion heater. And people say we get no sun here in the UK :laugh: .

 

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