Solar PV Hints, Tips & Troubleshooting

mp3guy · 25-02-2021 12:10pm

DrPhilG wrote: »

Thanks mp3guy

Does that mean that the battery (even a DIY version) could to be DC coupled behind the Solis inverter and then any other inverter used for the second set of panels?

I'm just trying to list all the equipment I would need in the event of going ahead with this.

Most likely I'll get the 9kWh battery initially, and whatever additional inverter is needed and get everything set up with room to expand.

Next would be the additional panels, and finally a further battery expansion.

Not sure about Solis's capabilities, and you would need to pick the right inverter that can support this. Provided neither inverter is capable of more than 6kW output, only one of them has to monitor the total export and scale itself down. But one of them has to be capable of export limiting.

irishchris · 25-02-2021 2:49pm

Was wondering if anyone can help me out here. I am finishing installation of 9x360w longi install and went to order one extra to finish it but suppliers now only have 365w in stock. There is a difference of 0.2 volts and 0.08A between the two modules. Would this be an issue or would it be ok?

slave1 · 25-02-2021 3:35pm

irishchris wrote: »

Was wondering if anyone can help me out here. I am finishing installation of 9x360w longi install and went to order one extra to finish it but suppliers now only have 365w in stock. There is a difference of 0.2 volts and 0.08A between the two modules. Would this be an issue or would it be ok?

Would have thought the extra lad will be pulled down to the vols and amps of the existing lowest common denominator which is immaterial from a total array perspective.
There could be other considerations that those more knowledgeable could add like impact on MPPT functionality

Or, could you not source elsewhere, I have to say I'd be triggered if the extra panel looked different also

irishchris · 25-02-2021 4:37pm

slave1 wrote: »

Would have thought the extra lad will be pulled down to the vols and amps of the existing lowest common denominator which is immaterial from a total array perspective.
There could be other considerations that those more knowledgeable could add like impact on MPPT functionality

Or, could you not source elsewhere, I have to say I'd be triggered if the extra panel looked different also

Cheers. Same model panels just 5w more. Attached the data sheet of it, appreciate any advice here from anyone. Solartricity advise it should be compatible but just double checking

unkel · 25-02-2021 5:22pm

If the only difference is the max amps of the 365W panel are higher than the same for the 360W panel, than you just lose the 5W extra of that last panel. Immaterial as slave1 says.

graememk · 25-02-2021 7:07pm

DrPhilG wrote: »

Thanks mp3guy

Does that mean that the battery (even a DIY version) could to be DC coupled behind the Solis inverter and then any other inverter used for the second set of panels?

I'm just trying to list all the equipment I would need in the event of going ahead with this.

Most likely I'll get the 9kWh battery initially, and whatever additional inverter is needed and get everything set up with room to expand.

Next would be the additional panels, and finally a further battery expansion.

You need to look at the whole picture now. Questions to ask yourself.

More storage
Are you ditching the pylon techs or getting a second stand alone Storage inverter?

Where are you putting it? All in your attic? Or in the Garage?
If in the Garage, How are you getting the power back to the house/main consumer unit.

Anything in the garage will need CT's run to it at least to measure the main feed from the grid and ideally the solar. Ie it needs to know if there is import/export to either charge or discharge the batteries.

As with the solis hybrids i dont know how they operate, I touched on this before, eg:

does it take the mppt feed and convert all to AC

then monitor the grid I/E and charge/discharge accordingly (from AC).

Or is it on the DC side with DC/DC converters.

- If its AC it would be able to pull power from more than one inverter but if its
DC it can only pull it from panels connected to it. I have a feeling it could be AC.

Charge rates, Take the ME3000 from sofar for example, the max it can charge or discharge at is 3kW.

I think the Solis Hybrid can do 5kW but that is battery dependant too!

Plans for going forward
If you left your current setup alone.
Storage inverter for the extra battery (in garage?)
Panel expansion with inverter in garage, with that one doing the export limitation.

A bit rambley i know but trying to cover most of the bases can be tricky

irishchris · 25-02-2021 9:18pm

One last question here on my setup. I see a lot of people discussing overpowering their inverters, or more panels than the rated inverter.

I'm in process of installing ground mount system and Solis inverter is a 3kw which states max DC 3.3kw. assuming this means I cannot go over 3.3kw input or is this just at perfect conditions? Have opportunity of extra 365w panel which would bring my new setup to 3.6kw. is this viable? Would be well within voltage limit and within max amps.

graememk · 25-02-2021 9:26pm

irishchris wrote: »

One last question here on my setup. I see a lot of people discussing overpowering their inverters, or more panels than the rated inverter.

I'm in process of installing ground mount system and Solis inverter is a 3kw which states max DC 3.3kw. assuming this means I cannot go over 3.3kw input or is this just at perfect conditions? Have opportunity of extra 365w panel which would bring my new setup to 3.6kw. is this viable? Would be well within voltage limit and within max amps.

Yep As long as your within the voltage and current limits, you could prob go 2-3 more!

irishchris · 25-02-2021 9:35pm

graememk wrote: »

Yep As long as your within the voltage and current limits, you could prob go 2-3 more!

Cheers Graememk, That's brilliant and will get that extra panel now.
So what is the idea behind the max DC wattage that they specify on the inverters?

DrPhilG · 25-02-2021 9:43pm

graememk wrote: »

You need to look at the whole picture now. Questions to ask yourself.

All good questions, and I'll be going through them with my installer before I do anything concrete.

A quick summary, by no means definite or final. Just ramblings as you say.

Basically the plan is to:
*Sell the PylonTech to fund the expansion.
*Buy about 10kWh of storage to replace it.
*Double both arrays, garage from 2.8 to 5.6kwp, house from 3.4 to 6.8kwp.
*one inverter in the house with the 6.8 connected.
*second in the garage with the 5.6 connected, and the battery.
*add additional storage for about 25-30kWh total.

3 stage plan, financially dependant.

1 - replace the PylonTech with either China sourced batteries like championc has, or my friend's 9kWh Leaf pack. Add the second inverter at that stage both to connect the batteries in the garage and to future proof for the panel expansion.

2 - add extra storage. If going Chinese, then I can add 8kWh (usable) packs for €1500 a time. If going Leaf cell, I can add about 20kWh for around €2500.

3 - double the panels. Either DIY or via previous installer depending on price. When I added a few panels on top of my original quote, he charged €200 supplied and fitted. Different story now though I'd imagine.

I have funds for stage 1 and 2 now, stage 3 in a year or so. Obviously no point in doing step 3 before 2, as I'd have no storage to handle all that extra juice.

My friend's Leaf pack, he has connected with a Victron inverter and a Batrium BMS setup. However (to be confirmed) the Leaf pack is connected via canbus which the Solis supports, so in theory (again tbc) I can connect the Leaf pack DC coupled, the same as the current PylonTech ones. Then the Solis inbuilt BMS would manage it.

So I could move the Solis to the garage along with the cells, and put a new 5kw standard inverter in the house.

Now as for the connections back and forth, I'm fairly in the dark and this is where I'd speak to the pros. I currently have 2 x 100m DC solar cables between house and garage which feed the garage panels to the inverter in the house. I also have underground cables connecting the fuse board in the garage (which the Zappi is connected to) back to the house. With a 7kw Zappi attached it's presumably a pretty heavy duty line.

Now how that would apply to my initial plan, I don't know. Can the power go back via the DC cables that are no longer needed to link the garage panels in? Can it go back via the cable from one fuse box to the other? There are a few ethernet lines from house to garage too already.

The thought did cross my mind to get a single 10kW inverter but those are seemingly as rare as hen's teeth, and also extortionately expensive so no point.

Anyway that's my ramble. Very vague and I'm sure there's a load of things in that plan that make no sense. But that's why you nice folk are here plus my installer will be on hand to make sure I don't blow anything up.

graememk · 25-02-2021 9:59pm

DrPhilG wrote: »

Now as for the connections back and forth, I'm fairly in the dark and this is where I'd speak to the pros. I currently have 2 x 100m DC solar cables between house and garage which feed the garage panels to the inverter in the house. I also have underground cables connecting the fuse board in the garage (which the Zappi is connected to) back to the house. With a 7kw Zappi attached it's presumably a pretty heavy duty line.

Now how that would apply to my initial plan, I don't know. Can the power go back via the DC cables that are no longer needed to link the garage panels in? Can it go back via the cable from one fuse box to the other? There are a few ethernet lines from house to garage too already.

As you have a zappi connected to the garage consumer unit, it would at least be a 6mm2 feeding it, more likely a 10mm2

(I have a 16mm2 going from my house to the yard, but its a long run)

I can't see any issue connecting the solar(or battery inverter/hybrid inverter) to that consumer unit as the AC power can flow each way as necessary.

Will have to use one of the ethernet cables to carry ct's back to the house consumer unit.

The DC cables would just not be used i think. if house inverter just ran house panels and garage inverter only ran garage panels.

Batteries in garage and just an inverter in the house would be a good way to go. Wouldn't personally feel comfortable with them attic.

DrPhilG · 25-02-2021 10:08pm

graememk wrote: »

The DC cables would just not be used i think. if house inverter just ran house panels and garage inverter only ran garage panels.

I could even shift both inverters to the garage, keep it all together, and use the DC cables the opposite to how they're used now.

graememk wrote: »

Batteries in garage and just an inverter in the house would be a good way to go. Wouldn't personally feel comfortable with them attic.

That was my thinking too.

Good to see that there are no obvious howlers in my ramble at least!

slave1 · 25-02-2021 11:12pm

Is it worth such an investment in these batteries when ....
a) night rate now so low with Energia EV plan
b) FIT coming in

graememk · 25-02-2021 11:57pm

slave1 wrote: »

Is it worth such an investment in these batteries when ....
a) night rate now so low with Energia EV plan
b) FIT coming in

More panels yep, battery.. well all you need is enough to peak shave and run out the clock until night rate kicks in.

My base load was nearly covered when the night rate stopped this morning.

DrPhilG · 26-02-2021 4:33am

slave1 wrote: »

a) night rate now so low with Energia EV plan

I just changed to a Energia a few months ago, then the buggers bring out that EV plan. Typical.

jprboy · 27-02-2021 2:21am

DrPhilG wrote: »

I just changed to a Energia a few months ago, then the buggers bring out that EV plan. Typical.

:eek: Me too, changed to Energia last Nov as best offer at the time

For me I'm seeing 16.64c(day) 4.78c(night) - all inc VAT in this offer.

Currently paying 14.22c day and 6.82 night (inc VAT)

Normally use much more proportionately at night during winter as have heat pump and EV.

However, working nearly full time at home since last March so EV charging costs slashed for now.

Therefore initial estimation is not much advantage for me in this EV plan but cannot give conclusive answer as number crunching function has been impaired due to wine/beer/whiskey consumption............

MAULBROOK · 27-02-2021 11:24am

DrPhilG wrote: »

I just changed to a Energia a few months ago, then the buggers bring out that EV plan. Typical.

Give them a call they might change you over if you ask nicely:D:D

slave1 · 27-02-2021 1:36pm

DrPhilG wrote: »

I just changed to a Energia a few months ago, then the buggers bring out that EV plan. Typical.

MAULBROOK wrote: »

Give them a call they might change you over if you ask nicely:D:D

I was going to jump on it but now with an install just a few months in and FIT coming in I'm going to sit back until the end of the Summer generation and FIT "constraints" are known, then decide.
Not a huge saving given I'm currently moving night duties to day, washing machine/dryer/immersion etc

the_amazing_raisin · 27-02-2021 7:43pm

MAULBROOK wrote: »

Give them a call they might change you over if you ask nicely:D:D

I tried that last year, they said because I'd signed up to a 12 month contract I couldn't change even when I offered to sign up to 12 months again

tsiklon · 27-02-2021 7:46pm

We're renovating an old house, which will require substantial work on the roof to bring it up to spec. We probably don't have the budget to purchase panels just yet.

What would we need to do now in order to have panels added at a later stage? What type of brackets etc are required?

championc · 27-02-2021 8:13pm

tsiklon wrote: »

What would we need to do now in order to have panels added at a later stage? What type of brackets etc are required?

You'll find the brackets and rails on either midsummer.ie or solortricity.ie. it certainly makes sense to mount the rails into the roof tiles now. Each row just needs to be mounted about 1m apart. And for gods sake, make sure your intended installation location is in a top or bottom corner.

the_amazing_raisin · 27-02-2021 10:52pm

tsiklon wrote: »

We're renovating an old house, which will require substantial work on the roof to bring it up to spec. We probably don't have the budget to purchase panels just yet.

What would we need to do now in order to have panels added at a later stage? What type of brackets etc are required?

I guess it'd be best to talk to the architect or structural engineer about it just to be sure the roof doesn't need reinforcement if you're putting a lot of panels up there

You'll probably be fine if the roof is being redone anyway

If you're planning on doing an attic conversion at any point it might be worth planning the skylights and panels around each other now

tsiklon · 27-02-2021 10:58pm

championc wrote: »

You'll find the brackets and rails on either midsummer.ie or solortricity.ie. it certainly makes sense to mount the rails into the roof tiles now. Each row just needs to be mounted about 1m apart. And for gods sake, make sure your intended installation location is in a top or bottom corner.

Thanks. Top or bottom corner is for access or routing cables?

unkel · 28-02-2021 12:01am

tsiklon wrote: »

Thanks. Top or bottom corner is for access or routing cables?

It is so you can install a lot more panels later

championc · 28-02-2021 9:18am

tsiklon wrote: »

Thanks. Top or bottom corner is for access or routing cables?

People plonk panels right in the center to make things nice and symmetrical. You want to be thinking about maximizing your space.

Of course too, ensure you plan the route for the cable and even pre-install that too, or at least the opening to get the cables from inside to outside.

If you go ahead with brackets, think about where the rails will go and then place the brackets accordingly. The mounting rails will be 2m or 3m long and can be joined with joiners. An ideal guide would be one bracket under the middle of each panel per rail, so they will be at about 1m spacing, since panels are roughly 1m wide. The space between both rails is possibly better for about 80cm since most panels are about 1.6m long.

insular1 · 28-02-2021 11:20am

championc wrote: »

People plonk panels right in the center to make things nice and symmetrical. You want to be thinking about maximizing your space.

Is there any point in taking this approach if you're already looking at getting the full 6kw system? Our roof could probably fit 10kw of panels and I'm looking at 6kw system quotes at the moment. Any chance the ESB limit of 6kw would ever be raised? I
Does anyone know is this a physical limit of single phase or just some random limit the ESB came up with that might be raised in future?

If 6kw is likely to be the max size ever allowed then I'd probably rather the panels were symmetrical.

MAULBROOK · 28-02-2021 12:09pm

insular1 wrote: »

Is there any point in taking this approach if you're already looking at getting the full 6kw system? Our roof could probably fit 10kw of panels and I'm looking at 6kw system quotes at the moment. Any chance the ESB limit of 6kw would ever be raised? I
Does anyone know is this a physical limit of single phase or just some random limit the ESB came up with that might be raised in future?

If 6kw is likely to be the max size ever allowed then I'd probably rather the panels were symmetrical.

Its the inverter thats limited to 6kw not the panels.

championc · 28-02-2021 12:28pm

insular1 wrote: »

Is there any point in taking this approach if you're already looking at getting the full 6kw system? Our roof could probably fit 10kw of panels and I'm looking at 6kw system quotes at the moment. Any chance the ESB limit of 6kw would ever be raised? I
Does anyone know is this a physical limit of single phase or just some random limit the ESB came up with that might be raised in future?

If 6kw is likely to be the max size ever allowed then I'd probably rather the panels were symmetrical.

6kW will deliver 6kW at the peak of the day, in perfect conditions, when the sun is at right angles to your panels. However, this is not reality. You ideally want your system to cover your base load, particularly on duller overcast days.

So to maximize FIT, it makes sense to maximize the installation if you have the roof space

insular1 · 28-02-2021 1:56pm

So in theory I can install 10kw of panels and just use a 6kw inverter? I'd limit my production to 6kw but that would only really be an issue for short periods in the summer. Is there any risk of overloading an inverter or frying it if I was producing 10kw?

championc · 28-02-2021 4:32pm

insular1 wrote: »

So in theory I can install 10kw of panels and just use a 6kw inverter? I'd limit my production to 6kw but that would only really be an issue for short periods in the summer. Is there any risk of overloading an inverter or frying it if I was producing 10kw?

You need to keep within the voltage limits of the proposed inverter. So total up the VOC. That's the bit that will blow the arse out of an inverter

mp3guy · 28-02-2021 10:17pm

SolarEdge allow pretty extreme DC oversizing in their inverters.

insular1 · 28-02-2021 11:27pm

This is all good to know. Thanks all. Will start asking for the max number of panels any company is willing to install and see what comes back to me.

Bobeagleburger · 01-03-2021 8:57am

Should moss on tiles be removed before the installing panels? Ideally I'd imagine, but does it matter?

the_amazing_raisin · 01-03-2021 9:12am

6 wrote: »

Should moss on tiles be removed before the installing panels? Ideally I'd imagine, but does it matter?

I don't think it'll cause any trouble, but you probably won't be able to clean it off afterwards so best to do it before installation

championc · 01-03-2021 9:24am

6 wrote: »

Should moss on tiles be removed before the installing panels? Ideally I'd imagine, but does it matter?

Absolutely no need at all. The panels will have a few inches of clearance between them and the roof

MAULBROOK · 01-03-2021 7:48pm

6 wrote: »

Should moss on tiles be removed before the installing panels? Ideally I'd imagine, but does it matter?

Only if your board and want to get away from the family for an hour or so.

Bobeagleburger · 01-03-2021 9:39pm

Thanks all. If I can get it done before the install I will, otherwise it can stay.

Geeyfds53573 · 02-03-2021 12:33am

https://www.rte.ie/news/business/2021/0225/1199450-electricity-smart-meters-go-live-for-250-000-households/
New smart meters go live today , there is a tariff of 5c per kWh between 2am-4am

graememk · 02-03-2021 12:45am

Geeyfds53573 wrote: »

https://www.rte.ie/news/business/2021/0225/1199450-electricity-smart-meters-go-live-for-250-000-households/
New smart meters go live today , there is a tariff of 5c per kWh between 2am-4am

I know this has been discussed in a few places... Wow a whole 2 hrs that's, frankly thats pathetic.. but the other rates are on par with EI's normal rates (really high, but give cashback to new customers to keep yearly bill down)

Actually interested in energias rates whenever they release them. The website is setup for it but no rates published tho.

graememk · 02-03-2021 12:58am

Oh they are up.. with them rates, I would lose money with a FIT!

irishchris · 02-03-2021 7:34am

Jeez between Airtricity, bord Gais, energia and electric Ireland the smart meter plans are so overpriced!! Typical Ireland and price gauging with similar priced plans between all the "competition"

graememk · 02-03-2021 8:05am

irishchris wrote: »

Jeez between Airtricity, bord Gais, energia and electric Ireland the smart meter plans are so overpriced!! Typical Ireland and price gauging with similar priced plans between all the "competition"

There currently is no incentive to switch from a standard meter,

I do support the multiple tariffs but not when the day rate is the same as the 24 hr day, then more for the evening peak and then the night rate is double their cheapest offer.

The standing charge, for SSE is 50 euro cheaper.

High cash backs can be beneficial to low useage too.

Still won't be jumping at a smart meter, even for a FIT.

Bobeagleburger · 02-03-2021 8:18am

Can you avail of FIT without a smart meter?

graememk · 02-03-2021 9:00am

6 wrote: »

Can you avail of FIT without a smart meter?

No the proposals are that you need a smart meter.

Standard meters don't measure export.

slave1 · 02-03-2021 9:19am

Batteries may reign on.....

the_amazing_raisin · 02-03-2021 11:11am

slave1 wrote: »

Batteries may reign on.....

With those tariffs you'd almost be cheaper going off grid :rolleyes:

unkel · 02-03-2021 11:23am

It's NEVER cheaper to go off grid

garo · 02-03-2021 12:00pm

graememk wrote: »

Oh they are up.. with them rates, I would lose money with a FIT!

Pathetic rates. And they clearly did not look at daily consumption patterns when setting the times. Shows such lack of imagination. You could easily start the night rate an hour earlier. And peak should really be from 1630 to 2000. With these rates takeup for FiT would be really poor. This is bad systems planning. Overall outcome for the country as a whole would be decidedly suboptimal.

slave1 · 02-03-2021 12:33pm

garo wrote: »

Pathetic rates. And they clearly did not look at daily consumption patterns when setting the times. Shows such lack of imagination. You could easily start the night rate an hour earlier. And peak should really be from 1630 to 2000. With these rates takeup for FiT would be really poor. This is bad systems planning. Overall outcome for the country as a whole would be decidedly suboptimal.

But is there any surprise in any of that, not being a smart arse, just my expectation that they'll all get together with slight variants of packages and rates and that not much would change, especially with ESB dictating

slave1 · 02-03-2021 12:36pm

unkel wrote: »

It's NEVER cheaper to go off grid

Isolated build is about the only time, you could start justifing it with huge ESB hook up costs but yes I have to agree, in Ireland with our low fixed charges it makes no (financial) sense.
I like seeing the US off-grids setups on YT, they are awesome, do what they want and noone to tell them otherwise, a lot of it has to do with the rights they give to their provider to access their property

Solar PV Hints, Tips & Troubleshooting

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