Solar for Dummies.

daheff

https://www.boards.ie/discussion/comment/119627004#Comment_119627004

Thanks for this.

EV isn't used as much as it was precovid, so going to night rate doesn't really make much sense.

I have the Zappi set to charge on the eco+ mode. It does mean that it charges at around 1.2kw/h, so slowly. But it makes better use of available solar. Still rarely charge at more than 40% solar over any period of time greater than an hour.

To connect the myenergi app to the zappi I think I need to also buy the hub(harvi?)

Really my array is small, doesn't produce much energy. I think I'd need to put money into it to do it right, but not sure the benefit is worth the costs and hassles.

Maybe the FIT is the best option to make some benefits.

I'd nearly be certain that the builder did not register the NC6 with the ESB, but will check it.

Thanks

AckwelFoley

Do batteries for solar need to be the same brand..

I'm due to get a Puredrive kw battery but of I want to down the line add another 5kw battery, do I need to get the same brand or can I shop around?

bullit_dodger

https://www.boards.ie/discussion/comment/119630940#Comment_119630940

Typically yes, they need to be the same brand - but not always. It's a good idea though as each battery manufacturer has their own profile. Voltages used, configuration, the BMS (battery management system) will like to see indentical profiles......although it's not 100% necessary.

Basically while "in theory" you can do what you are suggesting, in reality you'd probably be better off sticking to the one brand or you might run into issues.

AckwelFoley

Another quick question.

I know ow with the glycol solar setup, if one had east west, that when east was working, west wasn't and than it would transfer over when sun hit west

Is it the same with the PV, when east is generating west is idle. And vice versa or do both generate together albeit one higher than the other

graememk

https://www.boards.ie/discussion/comment/119640682#Comment_119640682

In short yes. Usually it's on different strings so that it's technically 2 separate/independant arrays and don't effect each other.

There was a paper out that tested matched east west on a single string and that worked just as well as two separate strings, although I think they needed to be mirrors of each other, eg 6 west and 6 east .

ELM327

https://www.boards.ie/discussion/comment/119631183#Comment_119631183

If you get a different but similar battery you should be fine.

I was looking at this and the likes of dyness and pylontech for instance should (in theory) work together as they are almost the same underneath.

redmagic68

https://www.boards.ie/discussion/comment/119640698#Comment_119640698

So if you’ve an east/west split only one array will generate at a time? I thought if the sun was on both that both would generate for example midday when the sun is in the south and would be shinning on both, only one array will generate even if they are separate strings on the inverter?

slave1

In an E/W split the E is String 1 usually and the W String 2, String 1+String 2 = Array 1

Just a loss in translation, an array is both strings together so the Array will generate off String 1 and String 2 at solar midday

DC999

Even when the sun is not on them, they will produce a small amount. So in the morning when West can’t see the sun, there is light bouncing around the sky so they pick that up. Output levels would be like that of a cloudy day.

You could put them on 1 string like a Fronius whitepaper @graememk mentions. I asked our installer if they wanted to try that with us as a proof of concept. And that they’d change back at no cost if didn’t get the output. They weren’t interested.

Paper does seem to suggest (from little of it I could understand as it’s technical) that the different between the roof angles needs be shallow. So an Irish roof isn’t typically. Some countries might have flatter roofs. Think they did it in Germany or Oz, can’t recall. But I could well have misunderstood that part

bullit_dodger

Good thing to do is take an actual example of an actual east/west split. This is from my own site and a good day in July last. I'm exactly 90/270 split.

You can see that the east panels shoot up very quickly when the sun comes over the neighbors house at 6:30am, and they "peak" about 11:30am, while the west facing panels peak about 3:30pm (solar noon is 1:30pm in Ireland in summer)

But even at 7-8am the west facing panels in the shade of the roof and not facing the sun are still doing "something"......just not a lot :-)

micks_address

hey folks - sorry if asked before.. is there generally much difference in solar invertors/batteries from a manufacturer point of view? ive a quote with a givenergy invertor and battery and im not sure if its gen1/gen2.. i'll ask but does it matter?

bullit_dodger

Between the various makes/models, no - they all pretty much do exactly what they say on the tin. Whichever one you get will for most people be perfectly fine. I have a Givenergy one myself and if you are planning on some automation, the remote management of it is 1st rate, probably best in market.

I would however make sure that you get a Gen2 model. The Gen1 are limited to 2600w charging/discharging rates from the battery while the Gen2 is limited to I beleive 3600w. Makes a huge difference if you are trying to charge a big battery in a short window (for example a 3 hr window at 2am on a smart tariff)

robwen

Do u need a WiFi hub to use the myenergi app, should one have been included with the installation or is it an extra, where do u buy one??

AckwelFoley

Another question..

I'm looking at the tariff that electric are offering. One is the night boost ie 2 hours at a lower rate than regular night.

If I have a 5 kw battery how long would it take to typically fill its boots with electricity. Would the 2 hours cover it? I'd consider getting 10kw batteries and more panels so less peak grid

Albeit a good month, the solar has exceeded my expectations, and yes I know December and Jan is going to be poor but I'd like to make best use of battery at that point

Redlim

Hi All. Apologies if this has been answered previously. Are there any downsides to using larger panels e.g. 550w/580w panels?

Assuming the installer is ok working with the larger size, is there anything to consider from the user standpoint? It might work out better for us to use these to get the most out of the small amount of space available to work with.

yankinlk

https://www.boards.ie/discussion/comment/119651576#Comment_119651576

I fill my battery slowly over the entire night rate by dialing down the amps...but yeah the default setup of solis filled it in 2 hours easily.

Punchin A Keyboard

https://www.boards.ie/discussion/comment/119652543#Comment_119652543

Depending on the size of the panels, you might be able to do some maths and see if you can jenga in more smaller panels which may give a higher overall kwp

micks_address

hi folks -

talking to an installer today about number of panels on back roof versus front roof of the house.. they recommended putting all on back as the ones on front would drain down the power if they werent getting sun? i thought they'd be different strings so would be independent? ive heard about optimisers if one panel is shaded it can take down the rest to its operating level

our back of house gets probably 60 percent of sun, with front getting the later afternoon sun..

Cheers,

Mick

ELM327

You should have string 1 and string 2. Just use string 2 for the front and 1 on the back. That installer is talking through their hoop tbh

micks_address

https://www.boards.ie/discussion/comment/119655521#Comment_119655521

yeah i think they are more of a diy type outfit.. didnt inspire confidence

TaurenDruid

https://www.boards.ie/discussion/comment/119655391#Comment_119655391

Yeah... wouldn't be using those guys. Definitely want two strings in that situation.

Redlim

Cheers, I had been playing around with the dimensions alright and it actually seems to work best with these larger panels. Just not sure if there are any downsides to consider with the much larger panels apart from the Tetris element.

DC999

@micks_address, as others say that's a walk away job. Usual craic that some installers want an easy life (only 1 roof so it's done in jig time) but bad design for you (as miss later afternoon sun).

AckwelFoley

This is where "solar for Dummies" was born out of hence why I created the thread because im still a bit unsure

A string is one loop of panels?

If you have shading on one one of the loops it effects all the panels on that loop. I have 2 rows of panels 2 x 8 on the one side of my roof south face ..I think..pv1 and pv2

All strings added together is an array

Shading only effects the string, not the array

2 strings can supply different KW levels at the same time if they're in different locations kn the site.

...I think

bullit_dodger

https://www.boards.ie/discussion/comment/119655391#Comment_119655391

On the surface it sounds odd, but it may be just a misunderstanding of wording. Also you haven't really outlined the orientation of the front and back roofs. You mention.....

our back of house gets probably 60 percent of sun, with front getting the later afternoon sun..

So, we can guess from that, that the front is west, or "west north west" facing......so the supplier telling you to put most/all of your panels on the more southernly facing roof might not be as bad advice as you previously though? Depends a little on shading, number of panels you want to install, orientation of the roof, any chimneys/trees shading , etc.

If you give details the folks here will give you options.

micks_address

https://www.boards.ie/discussion/comment/119656319#Comment_119656319

East west facing.. east at back of the house. they didn't seem to know about having the panels on their own strings..made some sort of joke about it not being a piano

bullit_dodger

https://www.boards.ie/discussion/comment/119655836#Comment_119655836

Yup - you got it spot on. A string is a collection of panels all hooked up in series. Forgive the crud drawing, but effectively it's like this.

Don't have to have the same number of panels on both strings (although you do in your case), and neither do they have to be on the same roof. So you could have string 1 on a east facing roof and string 2 on a west facing roof. As a result they will generate different power at different part of the day.

With both your stirngs on the same roof and with the same number of panels, they should nearly always unless there's some shading from a chimeny or something, be pretty close to each other in terms of power (which they are as it's only 1-2% difference)

AckwelFoley

https://www.boards.ie/discussion/comment/119656375#Comment_119656375

How many strings can an inverter take, is it limited to just 2. For example a solis hybred.

graememk

https://www.boards.ie/discussion/comment/119656413#Comment_119656413

For residential, it's 2

Commerical, 3 phase.. depends what you want really, I think there is 3 and 4 string out there, but sometimes it's better just going with more inverters

bullit_dodger

https://www.boards.ie/discussion/comment/119656433#Comment_119656433

And the next question that people ask..."how many panels can you have in a string?"

The answer is ... "it depends". Usually for reasons I won't go into, your inverter is limited to about 12 panels per string. There's also a power limit, that you shoudn't really go more than 50% higher in the panels than your inverter. E.g. if your inverter is 6Kw, then you shouldn't have more than 9Kw of panels. That's not an absolute rule, but it's the general guideline.

The 12 panels per string one though is fairly hard rule. You might (might!) sneak in 13, but generally 12 is the limit.