Solar PV Performance Thread - Post your monthly output

championc · 02-02-2020 11:43am #1

I think it would be very useful to post Solar PV monthly generation figures. Not only could it highlight a problem further down the road, but there many be many owners who are getting far less than they expected (or promised by an installer) and would welcome feedback from other owners.

Of course, there are so many factors involved. Your location in the country (or abroad for our international boardies), your array size, your array direction and the panels mounting angle.

championc · 02-02-2020 11:43am

garo wrote: »

January
Predicted: 81.5 (without taking shading into account)
Actual 71.0 - 4.8kw East/West - Dublin

handpref wrote: »

January - 83

5.4 East/West

wexfordman2 wrote: »

Jan 158kwh produced, 20kwh exported

6kwp south facing - east cork

joujoujou wrote: »

82.4 kWh produced in January.

4.3 kWp, facing SSW.

January - 75kw

2.7kw South Facing - South Dublin - 22 deg slope

Shefwedfan · 02-02-2020 12:14pm

So for Jan below are figures, it only started on evening of 24th

PV Generation this Month 36.10 kWh
Battery Throughput this Month 36.30 kWh
House Consumption this Month 232.10 kWh
Grid Import this Month 206.30 kWh
Grid Export this Month 4.10 kWh
CO 2 Saved this Month 0.036 T

19 x 330w panels SW facing

unkel · 02-02-2020 2:01pm

Shefwedfan wrote: »

19 x 330w panels SW facing

I am glad to see you did go with a very large system as I recommended

spose · 02-02-2020 3:05pm

80 from 4.7 e/w in Cork

Shefwedfan · 02-02-2020 3:19pm

unkel wrote: »

I am glad to see you did go with a very large system as I recommended

I started at 12 and just as it got closer I kept putting more on.....in the end I wanted more than 19 but they said it was the max allowed:P

garo · 02-02-2020 6:11pm

Might be an idea to also mention tilt as a panel on a 20 degree tilt will give less than one on 40. Mine is 24 so not great. But I wasn’t going to raise the roof angle!

unkel · 02-02-2020 7:50pm

Shefwedfan wrote: »

I started at 12 and just as it got closer I kept putting more on.....in the end I wanted more than 19 but they said it was the max allowed:P

There's no such thing as a max allowed number of panels or wattage of the panels. But yeah, your inverter is not allowed to be more than 6kW

markpb · 02-02-2020 9:31pm

46.8kWh the second half of January (new install)

We’re in south Dublin, with a 3.1kWp install. We have 5 panels on the side (hip roof facing SE) and 5 at the back of the house (facing SW). The website says 26 degree tilt but that’s probably only correct for one set of panels.

MAULBROOK · 03-02-2020 7:27pm

System 4.8kw SE north Wexford

2020
Jan 130.6 kw

2019
December 94 kw
November 120.8 kw

Getting 3 more panels added at the end of Feb.
The company are adding them for nothing as a thank you for some good sales leads.

unkel · 03-02-2020 9:26pm

Temporarily down to 2.9kwp and spotted today that I generated 5kWh yesterday and 6kWh today. Not so bad. South Dublin, south facing 2.9kwp

Cut the grass today from my off grid PV system in the shed. While my grid tied PV system was providing enough electricity for the house and the thirsty condenser dryer while the sun was out

Shefwedfan · 03-02-2020 10:26pm

Best day yet, 9.2kWh generated......as nobody in house battery filled up quickly and a huge amount dumped to grid :-(

Gumbo · 03-02-2020 10:30pm

3kW system in Dublin 11.
South facing.

Jan 2020 - 114.18 kWh generated.

_dof_ · 04-02-2020 12:37am

4.3kWp system in the midlands, SSW facing, no shade problems.
Jan 2020: 136kW generated

_dof_ · 04-02-2020 12:40am

Shefwedfan wrote: »

Best day yet, 9.2kWh generated......as nobody in house battery filled up quickly and a huge amount dumped to grid :-(

8.5 generated today

, but 4.5 donated to eirgid since I fully charged the battery last night:(

garo · 04-02-2020 5:39pm

_dof_ wrote: »

8.5 generated today , but 4.5 donated to eirgid since I fully charged the battery last night:(

Ouch. I suppose the time has come to check the weather before setting the battery to charge. Or possibly switch night charging off altogether.

Today was my best day of the year with output over 5kWh. I put the dishwasher and washing machine on timer before I left so my battery never got full and I exported very little. Currently restricted to 500W max charge to the Pylontech 2000 due to temperature so I am exporting unnecessarily. Charge is limited to 10A when battery is colder than 10C.

championc · 04-02-2020 6:56pm

garo wrote: »

Ouch. I suppose the time has come to check the weather before setting the battery to charge. Or possibly switch night charging off altogether.

Will your system allow you to maybe charge the batteries up to a specific SoC level, which would leave room for solar excess.

unkel · 04-02-2020 8:17pm

garo wrote: »

Charge is limited to 10A when battery is colder than 10C.

Out of a max 25A for a single Pylontech US2000?

That seems very restrictive. Where did you get those settings from and what way have you staggered them? Something like 0A below 0C, 5A up to 5C, 10A up to 10C and 25A above?

_dof_ · 04-02-2020 11:36pm

championc wrote: »

Will your system allow you to maybe charge the batteries up to a specific SoC level, which would leave room for solar excess.

Yeah, I've been playing the "guess-tomorrows-sunshine" game each night to try to decide the level I should charge the battery at night, it's a bit of fun:) The goal of the game is to have the battery full at sunset, but feeding in the absolute minimum to the grid.

I'm truly hopeless at the game though, on days I expect sun and only pre-charge to a low level, the sun fails to co-operate, so then I end up using more day-rate grid.

On days where the forecast is dull, and I fully charge, the bloody sun spends the whole day laughing down at me.

The met eireann app is useless too by the way for this sunshine forecasting, it's the one leading me down the wrong path....

I'll stop playing that game once the days get longer though, I hopefully won't need to charge at all at night.

wexfordman2 · 04-02-2020 11:46pm

_dof_ wrote: »

Yeah, I've been playing the "guess-tomorrows-sunshine" game each night to try to decide the level I should charge the battery at night, it's a bit of fun:) The goal of the game is to have the battery full at sunset, but feeding in the absolute minimum to the grid.

I'm truly hopeless at the game though, on days I expect sun and only pre-charge to a low level, the sun fails to co-operate, so then I end up using more day-rate grid.

On days where the forecast is dull, and I fully charge, the bloody sun spends the whole day laughing down at me.

The met eireann app is useless too by the way for this sunshine forecasting, it's the one leading me down the wrong path....

I'll stop playing that game once the days get longer though, I hopefully won't need to charge at all at night.

I have heard that some manufacturers are testing automating that feature, would be interesting to see it working.

KCross · 04-02-2020 11:49pm

wexfordman2 wrote: »

I have heard that some manufacturers are testing automating that feature, would be interesting to see it working.

It’s already done. Moixa have it up and running in the UK.

Energia are running a trial with Moixa at the moment with 20 of their customers.

_dof_ · 05-02-2020 12:22am

KCross wrote: »

It’s already done. Moixa have it up and running in the UK.

Energia are running a trial with Moixa at the moment with 20 of their customers.

Yeah I knew about the Moixa smart battery and its machine learning of your usage patterns and its ability to control the charging based on that and forecast sunshine. There's a very interesting interview with the Moixa CEO on the EV News Daily podcast a few months ago.

I didn't think they were available in Ireland, but I saw here that someone was quoted for a system including the Moixa. I didn't know about the Energia trial though.

Hopefully my system manufacturer AlphaESS will eventually come out with some software update to provide this smart functionality.

championc · 05-02-2020 12:36am

_dof_ wrote: »

Yeah, I've been playing the "guess-tomorrows-sunshine" game each night to try to decide the level I should charge the battery at night, it's a bit of fun:) The goal of the game is to have the battery full at sunset, but feeding in the absolute minimum to the grid.

I'm truly hopeless at the game though, on days I expect sun and only pre-charge to a low level, the sun fails to co-operate, so then I end up using more day-rate grid.

On days where the forecast is dull, and I fully charge, the bloody sun spends the whole day laughing down at me.

The met eireann app is useless too by the way for this sunshine forecasting, it's the one leading me down the wrong path....

I'll stop playing that game once the days get longer though, I hopefully won't need to charge at all at night.

Have you checked your data in terms of how much power is used to charge your batteries ? Assuming it's night rate and a 2 to 4 kw battery pack, that will cost feck all so realistically, you can therefore afford to charge up fully and if you end up exporting, then so be it. But ever kw you buy at night will still end up replacing day rate electricity one way or another. Up to about 10:00 each morning, I also suspect that you are using more than you generate, so since the night rate finishes at 08:00, you have two hours or so with of stored night rate power which can immediately be used.

_dof_ · 05-02-2020 12:54am

championc wrote: »

Have you checked your data in terms of how much power is used to charge your batteries ? Assuming it's night rate and a 2 to 4 kw battery pack, that will cost feck all so realistically, you can therefore afford to charge up fully and if you end up exporting, then so be it. But ever kw you buy at night will still end up replacing day rate electricity one way or another. Up to about 10:00 each morning, I also suspect that you are using more than you generate, so since the night rate finishes at 08:00, you have two hours or so with of stored night rate power which can immediately be used.

Yeah, it charges 5kWh at 10c night rate, and therefore saves using 5kWh of 20c day rate, so it's saving 50c a day anyway.

So this time of the year it's always going to be consumed, and it's feck all money anyway, but like I say it's a game, like a little challenge to see if I can predict the right level and see the battery graph rise all day from low to full on the free solar electricity, but if I've overcharged the night before, I end up filling the battery early in the day and then donating the remaining generation for the afternoon.

I'll probably get bored of the game soon enough anyway, especially since I'm so useless at it

Tonight, I've been optimistic, and decided on 25% charge. Hoping for lots of sun tomorrow

Zardaz · 05-02-2020 1:02am

_dof_ wrote: »

Yeah, it charges 5kWh at 10c night rate, and therefore saves using 5kWh of 20c day rate, so it's saving 50c a day anyway.

So this time of the year it's always going to be consumed, and it's feck all money anyway, but like I say it's a game, like a little challenge to see if I can predict the right level and see the battery graph rise all day from low to full on the free solar electricity, but if I've overcharged the night before, I end up filling the battery early in the day and then donating the remaining generation for the afternoon.

I'll probably get bored of the game soon enough anyway, especially since I'm so useless at it

Tonight, I've been optimistic, and decided on 25% charge. Hoping for lots of sun tomorrow

Do you have a diverter to boil the tank during the day when the battery is full?

_dof_ · 05-02-2020 1:56am

Zardaz wrote: »

Do you have a diverter to boil the tank during the day when the battery is full?

Not yet, I'll be getting one though.

Anyway, sorry for derailing the thread, back to people reporting their system's performance

wexfordman2 · 05-02-2020 9:11am

_dof_ wrote: »

Yeah, it charges 5kWh at 10c night rate, and therefore saves using 5kWh of 20c day rate, so it's saving 50c a day anyway.

So this time of the year it's always going to be consumed, and it's feck all money anyway, but like I say it's a game, like a little challenge to see if I can predict the right level and see the battery graph rise all day from low to full on the free solar electricity, but if I've overcharged the night before, I end up filling the battery early in the day and then donating the remaining generation for the afternoon.

I'll probably get bored of the game soon enough anyway, especially since I'm so useless at it

Tonight, I've been optimistic, and decided on 25% charge. Hoping for lots of sun tomorrow

Even if today is a fantastically sunny day, it will be near 10am before you get any usable production. So if you leave it at 25% charge and your discharge limit is 10%, then you have 9bly 15% available to you before 10am, which is what, 0.750kwh ?

garo · 05-02-2020 10:08am

unkel wrote: »

Out of a max 25A for a single Pylontech US2000?

That seems very restrictive. Where did you get those settings from and what way have you staggered them? Something like 0A below 0C, 5A up to 5C, 10A up to 10C and 25A above?

There seem to be only two restrictions in practice. You cannot charge at over 500W when the temperature is below 10C. And it doesn’t charge at all under 0C. Though it never really gets below freezing where my batteries are stored. It makes sense as you cannot beat chemistry. Link below has more info. You could get a LFP battery to take more charge but then you would be shortening its life. This is a BMS setting but unfortunately the manuals have no mention of this or a temperature defeating chart.

https://community.victronenergy.com/questions/8827/dvcc-limiting-charging-current-multigrid-venus-mpp.html

garo · 05-02-2020 10:21am

championc wrote: »

Will your system allow you to maybe charge the batteries up to a specific SoC level, which would leave room for solar excess.

Yes I have a Growatt inverter that allows charging based on both time and SoC. I haven’t tried night charging as I think the gains are marginal at best. You are reducing battery life by cycling so each battery charge and discharge will cost you something in the range of 5-10c.

championc · 05-02-2020 11:17am

garo wrote: »

Yes I have a Growatt inverter that allows charging based on both time and SoC. I haven’t tried night charging as I think the gains are marginal at best. You are reducing battery life by cycling so each battery charge and discharge will cost you something in the range of 5-10c.

I overnight charge to 80% each night and can get all the way to 23:00 the following evening meaning that I'm no longer using any daytime rate electricity

Of course, it's only possible with my 16.8kw of Lead-Acid AGM"s !!!

However, batteries will never pay for themselves. I got my batteries for free. Battery technology will change before their useful life has expired.

unkel · 05-02-2020 1:44pm

garo wrote: »

There seem to be only two restrictions in practice. You cannot charge at over 500W when the temperature is below 10C. And it doesn’t charge at all under 0C. Though it never really gets below freezing where my batteries are stored. It makes sense as you cannot beat chemistry. Link below has more info. You could get a LFP battery to take more charge but then you would be shortening its life. This is a BMS setting but unfortunately the manuals have no mention of this or a temperature defeating chart.

https://community.victronenergy.com/questions/8827/dvcc-limiting-charging-current-multigrid-venus-mpp.html

That seems to be a discussion on a Victron forum

Did you check the manual, or with Pylontech tech support about charging amps at lower temps? 10A at just under 10C seems unnecessarily restrictive to me

This will kill a lot of your potential on a sunny winter's day where you can easily see say 1300W out of a 4kwp system. With a 300W base load that means that at 10A restriction only half above the 300W will go to battery, the other half will be lost into the grid

garo · 05-02-2020 4:27pm

The person on that thread posts a response from Pylontech customer service.

Hi Kay,

Thank you choose our product!

Just like telephone battery cell, all normal lithium battery will get hurt in low temperature working condition specially in charging mode. For longer cycle of life and calender life we limit the current in low or high temperature. You can google the knowlage of "Lithium dendrites" if you have interesting.

So our BMS of battery work together with inverter to limit the current to protect our battery cells. It is intelligent design.

My proposal is:

Install a heating system for our battery (heat in the cabinet). Rise the temperature above 10℃. And the battery's comfortable temperature is 18~28℃.
Thanks and best regards!

Yes it does result in unnecessary export to the grid. I'm not sure what I can do to fix this.

unkel · 05-02-2020 8:41pm

He acknowledges that the BMS will not let you charge the battery below 0C, which is sound. But he is nowhere suggesting that the amps should be limited to 10A under 10C, is he?

And installing a heating system is a pretty terrible suggestion. It will cost more to run than the solar will generate that day. But sure it will protect the battery and that is all the battery manufacturer is interested in. Tesla does this too in the Powerwall. Wait till Sir Liamalot reads this, he'll have a right rant

I'd say use common sense instead...

garo · 05-02-2020 10:03pm

Read the thread will ya. The response from Pylontech was to a question about limiting charge to 10A per battery.

And yes heating the battery is a terrible idea.

unkel · 05-02-2020 11:43pm

garo wrote: »

Read the thread will ya. The response from Pylontech was to a question about limiting charge to 10A per battery..

Am I missing something? The problem was the guy was wondering why if he switched on a function (dvcc), presumably on his Victron or his inverter and nothing to do with the battery itself that the Pylontech batteries (!) charged slower

And the answer from Pylontech was:

"Hi Kay,

Thank you choose our product!

Just like telephone battery cell, all normal lithium battery will get hurt in low temperature working condition specially in charging mode. For longer cycle of life and calender life we limit the current in low or high temperature. You can google the knowlage of "Lithium dendrites" if you have interesting.

So our BMS of battery work together with inverter to limit the current to protect our battery cells. It is intelligent design.

My proposal is:

Install a heating system for our battery (heat in the cabinet). Rise the temperature above 10℃. And the battery's comfortable temperature is 18~28℃.
Thanks and best regards!"

Which is a very vague answer with no specs / parameters

joujoujou · 06-02-2020 12:09am

Nice day, nice result, I'd say.

garo · 06-02-2020 2:07pm

unkel wrote: »

Am I missing something? The problem was the guy was wondering why if he switched on a function (dvcc), presumably on his Victron or his inverter and nothing to do with the battery itself that the Pylontech batteries (!) charged slower

Which is a very vague answer with no specs / parameters

Agreed the answer is vague but I have searched the web and anecdotally there is charge limiting under 10C. This link has more info: https://batteryuniversity.com/index.php/learn/article/charging_at_high_and_low_temperatures
Stands to reason that slower charging at lower temps helps preserve battery life. There is nothing in the manual indicating this si I will have to wait for a sunny warm day to confirm what I have observed.

unkel · 06-02-2020 5:36pm

If it was my battery, I'd give it the full amps from about 5C. Provided the BMS hasn't already some more sophistication built in other than temp <0C => charging is a no no

garo · 06-02-2020 6:10pm

I do believe this charge limiting is coming from the BMS. Any idea how to access the BMS settings?

MAULBROOK · 06-02-2020 9:00pm

Lads can we keep this on track.

Solar PV Performance Thread - Post your monthly output

garo · 07-02-2020 10:50am

Thanks for the reminder. Could a mod move this discussion to the other thread?

MAULBROOK · 26-02-2020 8:24pm

Good day today 18'1 kw.
7 kw battery full by 1pm and water heated.
Getting better day by day.

Shefwedfan · 26-02-2020 8:39pm

Oh I’m all excited now with a full month performance nearly here to see how it’s going

championc · 27-02-2020 10:20am

Interesting to note this morning that @ 09:00, with the sun at 13 deg high and off to the South East , my panels output was broadly similar to 21 Dec when the sun was at high noon due South, when also at 13 deg. So there is no great difference as to the direction from which the sun is shining, but all about the angle the sun hits your panels.

The following link is very useful - https://www.timeanddate.com/sun/ireland/dublin?month=2&year=2020

garo · 27-02-2020 5:50pm

Yeah good link. The orientation does matter depending on your panel tilt. Shallower tilts make orientation less relevant.

PS: Best day so far. Already at 12kWh at 1650 for a 4.8kW E/W system.

championc · 27-02-2020 6:03pm

garo wrote: »

Yeah good link. The orientation does matter depending on your panel tilt. Shallower tilts make orientation less relevant.

PS: Best day so far. Already at 12kW at 1650 for a 4.8kW E/W system.

Me too - I'm at 8.92kw @ 17:00 for 2.7kw South Facing

Winterman1234 · 27-02-2020 7:30pm

Best day yet here also(installed 31st of January), 6.4kWh from a 2.5kW system facing S-SE located Donegal

rolion · 27-02-2020 10:56pm

AND...happy harvesting to all of you, days longer, Sun waking up higher and happier on the sky...

Today, got 14.9KWh closing in the 12.9MWh

PV diverter, injected in the cylinder a mere 8KWh.

eamon_l · 29-02-2020 12:21pm

2.7kWh produced do far today despite the storm warnings. South Dublin, 4.2kWh system east/west split (4/10). Very happy since my system was reconfigured.

Shefwedfan · 29-02-2020 1:44pm

Those with givenergy, is the website down? I cant get on since Thursday

championc · 29-02-2020 7:53pm

championc wrote: »

January - 75kw

2.7kw South Facing - South Dublin - 22 deg slope

February - 121.55kw

Solar PV Performance Thread - Post your monthly output

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