Solar PV Performance Thread - Post your monthly output

garo

garo wrote: »

4.8 kWp E/W. 2.4kWh battery. 24 degree slope.
October(kWh):
Production: 219 (200 predicted)
Consumption: 701 (512 pred.) ~120kWh in the car so prediction is off. Also WFH effect.
Import: 494 (225d, 269n) (342 pred.)
Export: 12 (30 pred.)

Best day: 2nd: 14.5
Worst day: 13th: 1.1

4.8 kWp E/W. 2.4kWh battery. 24 degree slope.
November(kWh):
Production: 113.5 (100 predicted)
Consumption: 740
Import: 636 (289d, 347n) 60kWh night rate charging.
Export: 3 (3 pred.)

Best day: 3rd: 6.7
Worst day: 24th: 0.8

bod71

bod71 wrote: »

Dublin South. 4kw split. SE/NW. Sept gen. 235kwh. Oct gen. 130kwh.

Nov gen.74kwh. Low sun shade on SE string, NW string getting v little sun.

DrPhilG

DrPhilG wrote: »

October Stats
6.2kWp (2.8 south/3.4 west), 4.8kWh battery, Zappi & Eddi – Donegal

Generation – 254.3kWh
Export – 13.3kWh
Import – 383.5kWh

Eddi - 21.3Kwh
Zappi - 71.6kWh

Best day - 1st, 20.9kWh
Worst day - 4th, 0.4kWh!

November Stats
6.2kWp (2.8 south/3.4 west), 4.8kWh battery, Zappi & Eddi – Donegal

Generation – 106.4kWh
Export – 0.6kWh
Import – 520.4kWh

Eddi - 3.5Kwh
Zappi - 86.5kWh

Best day - 6th, 8.5kWh
Worst day - 23rd, 0.5kWh


Totals so far:
August - 572.1kWh
September - 437.2kWh
October - 254.3kWh
November - 106.4kWh

December prediction - 86.8kWh (optimistic given how sh*t November was up here)

garo

For reference I had the following production over last winter:
Nov - 116
Dec - 96
Jan - 125
Feb - 215

And peak month:
May - 767

Mickeroo

July: 191.7kWh (logging only started on the 17th)
August: 397.8kWh
September: 299.1kWh
October: 226.1kWh
November: 72.5kWh (Ouch!)

Rzeznik

Rzeznik wrote: »

Near Drogheda, West facing, 2,48kW

Generation:
Aug'20: 220,4kWh
Sep'20: 186,4kWh
Oct'20: 110,4kWh

Nov was poor. 45kWh generated.

slave1

Partial month as just had install done, midlands, 76.6kWh generated off 4.1kw with bad shading just after noon'ish, I have optimisers and extra string to come on board still so hopeful for more when system fully up and running as planned

tails_naf

6.4 KWp, SSE facing.
163KWh generated.
600KWh consumed - though that's coloured by the amount diverted.
1 KWh sent to grid.
Charged 4.8 KWh battery full on 6 days.

Daily generation stats:

Gazzler82

Cork SE 3kw

Nov 54.7kwh produced*
Best day 4/11 6kwh
Worst 12/11 0.1kwh

*new broadband router put in so 3 days production missing and haven’t had a chance to check inverter. Doubt it will in crease in massively 😞

handpref

5.4kwp
East West
Louth

October 198kwh
November 83kwh

Are people still choosing not to kill off their batteries health early by daily night rate charging and day discharging of their batteries ?

Would it be more environmentally friendly to use up the grids night rate excess of renewables ?

After a total nightmare with the installer I’d hoped to get as much longevity out of the system as I can..

championc

handpref wrote: »

5.4kwp
East West
Louth

October 198kwh
November 83kwh

Are people still choosing not to kill off their batteries health early by daily night rate charging and day discharging of their batteries ?

Would it be more environmentally friendly to use up the grids night rate excess of renewables ?

After a total nightmare with the installer I’d hoped to get as much longevity out of the system as I can..

I'm charging my batteries to 100% each night and discharging to 20% remaining. I stop charging at 08:00, so by 11:00, even with some sun, I'll have lost a good few %. Even sun at noon is only generating 1.2kW at this time of year, but a lunchtime sun would possibly get me back up to 100%. I will gradually discharge throughout the late afternoon and evening, and on many nights, right up to 23:00 when night rate kicks in. So I get many days on 100% night rate now

MAULBROOK

championc wrote: »

I'm charging my batteries to 100% each night and discharging to 20% remaining. I stop charging at 08:00, so by 11:00, even with some sun, I'll have lost a good few %. Even sun at noon is only generating 1.2kW at this time of year, but a lunchtime sun would possibly get me back up to 100%. I will gradually discharge throughout the late afternoon and evening, and on many nights, right up to 23:00 when night rate kicks in. So I get many days on 100% night rate now

Doing the same. Charging from 3am till 8am, getting till mid night if i generate between 5kw to 7kw during the day.

7kw BYD battery

tails_naf

championc wrote: »

I'm charging my batteries to 100% each night and discharging to 20% remaining. I stop charging at 08:00, so by 11:00, even with some sun, I'll have lost a good few %. Even sun at noon is only generating 1.2kW at this time of year, but a lunchtime sun would possibly get me back up to 100%. I will gradually discharge throughout the late afternoon and evening, and on many nights, right up to 23:00 when night rate kicks in. So I get many days on 100% night rate now

What size batteries do you have? A 100% full battery for me during the day gets me to 6:30 pm at most. Usually the oven cooking for dinner finishes it off! Looking forward to summer when I'd hope thr batteries will be charging away until 9pm so will get thw rest of the day and some night using the batteries..

championc

MAULBROOK wrote: »

Doing the same. Charging from 3am till 8am, getting till mid night if i generate between 5kw to 7kw during the day.

7kw BYD battery

You should stop discharging at 23:00 because it makes no sense to discharge solar gained power during off-peak hours, to use it all up, and have to charge it up again. So if you had 35% left at 23:00, it means you only have to charge 65% rather than 80% or whatever.

MAULBROOK

championc wrote: »

You should stop discharging at 23:00 because it makes no sense to discharge solar gained power during off-peak hours, to use it all up, and have to charge it up again. So if you had 35% left at 23:00, it means you only have to charge 65% rather than 80% or whatever.

good point, tks

championc

MAULBROOK wrote: »

good point, tks

If you charge from 23:00 to 08:00, this should stop discharging during that timespan. If you're like me and want to keep your charging and discharging to the same day, you might be able to set charging between 23:00 and 00:00 with 0w or maybe a charge to 10%, meaning it would charge nothing, but not discharge either

MAULBROOK

championc wrote: »

If you charge from 23:00 to 08:00, this should stop discharging during that timespan. If you're like me and want to keep your charging and discharging to the same day, you might be able to set charging between 23:00 and 00:00 with 0w or maybe a charge to 10%, meaning it would charge nothing, but not discharge either

Funny that, I just changed to 23:00 to 08:00.
God I need a hobby or beer.

championc

MAULBROOK wrote: »

Funny that, I just changed to 23:00 to 08:00.
God I need a hobby or beer.

I do my charging after midnight to confirm my battery efficiency. The day before yesterday, I charged with 8.22kWh and discharged with 7.41kWh - so just over 90%

handpref

championc wrote: »

I'm charging my batteries to 100% each night and discharging to 20% remaining. I stop charging at 08:00, so by 11:00, even with some sun, I'll have lost a good few %. Even sun at noon is only generating 1.2kW at this time of year, but a lunchtime sun would possibly get me back up to 100%. I will gradually discharge throughout the late afternoon and evening, and on many nights, right up to 23:00 when night rate kicks in. So I get many days on 100% night rate now

Nice one -
I think the savings for me with the 5kwh battery would only be about €45 over the 4 months of winter.
I may save €45 by using the night rate but it’s also another 120 full charge and discharge cycles on the batteries. That’s 1200 cycles over 10 years.
I guess it’s being a bit pedantic but the batteries weren’t cheap and I’d like to get what I can out of them.
I may also be mistaken for a grow house given that the cars charge alternately between 11pm and 7am...not including the dish washer and washing machine !

unkel

handpref wrote: »

Nice one -
I think the savings for me with the 5kwh battery would only be about €45 over the 4 months of winter.
I may save €45 by using the night rate but it’s also another 120 full charge and discharge cycles on the batteries. That’s 1200 cycles over 10 years.

But that winter charging pays €450 towards them (haven't checked your calculations, but they look roughly right). That's a significant portion of what they cost you if you got the subsidy. The extra 1200 cycles aren't going to kill the battery off and in 10 years time batteries are likely a lot cheaper than they are now (and / or we have a FIT and / or you can use your EV as a power wall with V2G). No need to preserve the batteries now in case none of that happens (unlikely)

KCross

unkel wrote: »

The extra 1200 cycles aren't going to kill the battery off...

It wont kill it but it will reduce its lifespan. Thats a certainty. Alot of these batteries are designed for 3000-5000 cycles.... saving 1200 of those cycles for full daytime usage is a good idea.

unkel wrote: »

and in 10 years time batteries are likely a lot cheaper than they are now...

Battery production is going to be soaked up by EV's. Tesla increased the price of their powerwall and reduced supply because they needed the car production more. As other OEM's ramp up demand for batteries, the supply for domestic systems could be affected. Anyones guess what way the prices would go but I wouldnt be saying its "likely a lot cheaper".... the big price drops on batteries have already occured really ($1000/kWh+ in ~2010 down to <$100/kWh now).

unkel wrote: »

No need to preserve the batteries now in case none of that happens (unlikely)

Bad advice in my opinion. handpref has the right idea.

I'd even question if you'd save the €450. The round trip efficiency for charging and discharging the battery along with the reduced lifespan, i'd say you'd be lucky to save anything.

unkel

And so you would end up with a 10 year old battery that still has half of its cycles left. Which will be worth only a fraction of what they cost today. And will give a continued saving of far less than it would today (because we'll likely have FIT by then)

Technically you are 100% correct. But it's a bit like the people telling me not to overclock the CPU in my PC back in the day. As it would shorten its lifespan. For sure it would, but after 3 years it would have been obsolete anyway. Never mind trying to make it live to 10 years and beyond

Efficiency BTW of LiFePo4 is in the ballpark of 80-90% for a round trip. Hardly worth taking into consideration. For anyone who has already bought the battery (whether that was wise or not is another matter), in most cases it makes financial sense to load it up at night with night rate during winter

slave1

Load it up at night, battery life is all about BMS as well as life cycles, it's not as if the battery will be dead as a door nail bang on 10 years to the day. Current Pylon's have 90% DOD so that's plenty of buffer even if you go down to zero, myself I have it set to never go lower than 20% and top it up to 100% on night rate.
It's not as if this will be required 100% of the year come the high summer months

handpref

slave1 wrote: »

Load it up at night, battery life is all about BMS as well as life cycles, it's not as if the battery will be dead as a door nail bang on 10 years to the day. Current Pylon's have 90% DOD so that's plenty of buffer even if you go down to zero, myself I have it set to never go lower than 20% and top it up to 100% on night rate.
It's not as if this will be required 100% of the year come the high summer months

Great advice as usual from all with a deep depth of knowledge- many thanks

jimmyging

6.1 kw system
Nov production 114kw/hrs ......

mp3guy

championc wrote: »

You should stop discharging at 23:00 because it makes no sense to discharge solar gained power during off-peak hours, to use it all up, and have to charge it up again. So if you had 35% left at 23:00, it means you only have to charge 65% rather than 80% or whatever.

Sorry, not understanding the logic behind this? Why not discharge it fully? The solar put into the battery was free.

graememk

mp3guy wrote: »

Sorry, not understanding the logic behind this? Why not discharge it fully? The solar put into the battery was free.

If you have night rate, you don't want to waste your valuable solar replacing night rate usage

mp3guy

graememk wrote: »

If you have night rate, you don't want to waste your valuable solar replacing night rate usage

So if you have enough energy in the battery (from solar) to bridge the gap from when night rate ends in the morning until the sun comes out (say 8am until 9 or 10 in the winter?). Of course from when the sun goes down until night rate you discharge then also.

The window in the morning on day rate (or maybe through out the day after you haven't gotten any solar charge) is the idea? But I guess during periods of time you have a lot of solar, you would want to discharge at least most of it over night and pay for nothing.

This could be tricky if you end up with surplus unexpectedly, would need to use a solar energy forecast to optimize day to day to decide how much of the battery to allow to discharge over night and how much to save to fill the holes on poor yield days.

graememk

mp3guy wrote: »

So if you have enough energy in the battery (from solar) to bridge the gap from when night rate ends in the morning until the sun comes out (say 8am until 9 or 10 in the winter?). Of course from when the sun goes down until night rate you discharge then also.

The window in the morning on day rate (or maybe through out the day after you haven't gotten any solar charge) is the idea? But I guess during periods of time you have a lot of solar, you would want to discharge at least most of it over night and pay for nothing.

This could be tricky if you end up with surplus unexpectedly, would need to use a solar energy forecast to optimize day to day to decide how much of the battery to allow to discharge over night and how much to save to fill the holes on poor yield days.

Most people don't have an array the size you have.. so batteries rarely last that long anyway. So if you can save some for the morning.

Yeah if you carry over a bit to the next day usually won't be the worst in the world to ride out the morning.

But if your finding your carrying over too much, maybe knock it off in the summer,

But you really don't want to be putting your valuable battery power into a EV,

championc

mp3guy wrote: »

So if you have enough energy in the battery (from solar) to bridge the gap from when night rate ends in the morning until the sun comes out (say 8am until 9 or 10 in the winter?). Of course from when the sun goes down until night rate you discharge then also.

The window in the morning on day rate (or maybe through out the day after you haven't gotten any solar charge) is the idea? But I guess during periods of time you have a lot of solar, you would want to discharge at least most of it over night and pay for nothing.

This could be tricky if you end up with surplus unexpectedly, would need to use a solar energy forecast to optimize day to day to decide how much of the battery to allow to discharge over night and how much to save to fill the holes on poor yield days.

I made the statement relating to Winter, where I charge my batteries up to 100%. So from 08:00 to maybe 10:00, you are discharging.

So suppose your battery is 5kWh and you discharge 4kWh by 23:00. You then only have to charge it by 4kWh at cheap rate rather than by 5kWh.

During the summer, you are more likely to have more remaining and you are less likely to be charging overnight, in which case, you'd really not have any need to be looking at charging since sunrise will be before 09:00, when night rate ends at that time if year.