Domestic solar PV quotes 2018

garo

Sir Liamalot wrote: »

Cost of enerergy extracted from battery + cost of night rate electricity ≠ profit compared to day rate electricity.

Yes I agree on this. Best case you save 1-2c. Worst case you lose 4-5c or more. Not worth it financially in my opinion. And the environmental cost for the marginal best case gain doesn’t justify it either. Best case you are saving about €20 a year. Is a 2000 Euro investment in batteries worth it?

unkel

Sir Liamalot wrote: »

Cost of enerergy extracted from battery + cost of night rate electricity ≠ profit compared to day rate electricity.

We can measure this & all I have said.

That's too much of a generalisation.

If you pay the going rate for a lithium battery, you will lose money doing this. If you got your lithium battery as part of the €3,800 subsidy, it is borderline as garo has demonstrated a few times. But if you got a lead acid battery very cheaply or for free you sure will make a profit loading it up with night rate in winter.

murphaph

listermint wrote: »

What's a firefighter shunt

I assume it's the same as the fireman's switch we have (optionally) here in Germany. The problem with PV (typical setups with no module level optimisers) is that in the event of fire the fire brigade can't pull the main breaker and be sure than the house is safe (electrically) to fight the fire in. You can still have hundreds of volts of DC coming down from the roof even if the main breaker (I assumed the fire brigade in Ireland can open the mini-pillar, if fitted, outside and interrupt supply, they can here anyway) is open. In some places here such fireman's switches with appropriate relays/bypass diodes are required and some fire brigades will not fight the fire inside the building if there is PV on the roof which can't be isolated to bring the voltage down to safe levels.

air

I have recently seen lithium modules (complete with BMS) at close to €200/kWh ex VAT so storage may become much more viable in the medium term.

This is pricing direct from the manufacturer but bodes well.

unkel

air wrote: »

I have recently seen lithium modules (complete with BMS) at close to €200/kWh ex VAT

That's pretty good. Any link?

air

unkel wrote: »

That's pretty good. Any link?

No link sorry, B2B pricing only.

Only mentioned it as an indicator of where things are at currently at that level.
It should trickle down to us mere mortals eventually.

Northumberland

garo wrote: »

@ Northumberland How much are you getting the Pylontechs for? Be prepared for not getting your money back for 8-10 years. Also charging at night is marginal at best. You save maybe 1-2c at most. Given winter is approaching if I were you I would wait till March. Batteries could likely be another 10% cheaper by then. Lithium wholesale prices have come down a lot in the last couple of years.

Garo, I have a place in Dublin with an online presence, but they say I can pick up a Pylon 2.4kW US 2000 for Euros 936 plus E 215 VAT - this is probably not the cheapest, but if you do not get a unit in Ireland or the UK freight is large because of the Li battery restrictions. Please pm me on dalnwick@gmail.com if you know of better dealls.

I do not really understand your statement 'charging at night is marginal at best', I pay 50% or slightly less per unit of electricty used between midnight and 9am (summer), so if I can store that in my batteries (at what 98% efficiency? less?) and then use it in the day instead of paying full price, surely I am saving? since I only have 5kW of battery storage, I will of course only save 50% of the daytime cost of 5KW, but that is more than '1- 2 c', or did I mis understand you there?

air

Northumberland wrote: »

Garo, I have a place in Dublin with an online presence, but they say I can pick up a Pylon 2.4kW US 2000 for Euros 936 plus E 215 VAT - this is probably not the cheapest, but if you do not get a unit in Ireland or the UK freight is large because of the Li battery restrictions. Please pm me on dalnwick@gmail.com if you know of better dealls.

I do not really understand your statement 'charging at night is marginal at best', I pay 50% or slightly less per unit of electricty used between midnight and 9am (summer), so if I can store that in my batteries (at what 98% efficiency? less?) and then use it in the day instead of paying full price, surely I am saving? since I only have 5kW of battery storage, I will of course only save 50% of the daytime cost of 5KW, but that is more than '1- 2 c', or did I mis understand you there?

When you subtract the cost of cycling the battery (total cost/(number of lifetime cycles * kWh capacity)) you're not better off than just using daytime electricity is what he's saying.
When you allow for the cost of capital you're probably losing money in reality.

Northumberland

air wrote: »

When you subtract the cost of cycling the battery (total cost/(number of lifetime cycles * kWh capacity)) you're not better off than just using daytime electricity is what he's saying.
When you allow for the cost of capital you're probably losing money in reality.

Ok, I understand that. But that is really only true if the only justification for batteries is storing cheap night electricity. It is less true (but I accept still partially true) if the batteries are there primarily to store absolutely free electricity from the sun (free of course less depreciation of panels), which is the case with my set up. So, having installed the batteries (one of which will hopefully be almost free thanks to SEAI grant if it ever comes) to store panel generated electricity, it obviously makes sense to use them to store night rate power as well. But I think what he is underlining is the general premise that it is economically the very best to use as much of the energy generated from the panels at the same time that it is generated, hence the argument about panel orientation to try to maximise the time that the panels generate a useful current.

unkel

Northumberland wrote: »

it obviously makes sense to use them to store night rate power as well.

Nothing obvious about that! Your battery will have a much shorter life span if you load it up with night rate power. The additional benefit (10c saving per kWh) does not weigh up against the extra cost of the shorter life span, or at best there is very little profit in it - garo has done the sums in this thread. Look it up.

Northumberland

unkel wrote: »

Nothing obvious about that! Your battery will have a much shorter life span if you load it up with night rate power. The additional benefit (10c saving per kWh) does not weigh up against the extra cost of the shorter life span, or at best there is very little profit in it - garo has done the sums in this thread. Look it up.

Hmm, ok, food for thought and perhaps action!

Northumberland

Garo, Unkel, I have re-read Garo's nice post ( of 16th Sept 2019 if others want to find it easily) on the maths and economics of battery storage, particularly charging batteries overnight on cheaper night rate tarrif. Garos maths clearly warrants a cautious approach. But my question to you two is this - Garo's assumption appears to be that the batteries would be completely discharged before midnight (or 11pm in winter), then completely re-charged by 9 am or 8am from overnight charge, then discharged again in the low sun morning hours, charged up around 3pm from mid-day sun and discharged again in the evening, so there would be 2 nominal charges and discharges each 24 hours, eating in to the 10 k cycle life of the batteries. Depending on how the hybrid inverter/charger is set, this may well be close to reality. But with a large enough bank of batteries (expensive I know) there would seem to be the possibility of managing the charge/discharge times so that perhaps there was only one complete charge/discharge cycle per 24 hours. In most battery systems, particuarly electic cars (I have a Leaf) it is rare to go from completely discharged (or 10%) to completely charged - It is more usual to go from 30% up to 80% then down to 40% back to 85% etc, do all of those half or one third cycles count as full cycles in the batteries life, and eat in to the 10k cycles, or do they indeed count as just half cycles in the life expectation? In essence, my question is, is there a careful way of managing or manipulating the charge discharge cycles so as to change the economic maths away from Garo's calculations in favour of doing some re-charging at night, but perhaps not complete re-charging of the battery bank?

air

The short answer is nobody knows. You would need detailed performance data on your proposed battery as well as an estimated usage pattern in order to model various usage scenarios.

One thing in favour of night rate cycling is that batteries have a calendar lifetime as well as a cycle life so it may make a little more sense from that point of view to cycle them more while you have them.

It also gives you a bit more protection against power cuts if you have an essential load setup as the battery will be fully charged more of the time.

All told though I'm not convinced it's worth the hassle, charging from excess PV that would be otherwise exported for free is a much better business proposition.

garo

Yes Unkel has it right. One Pylontech 2000 is costing you €1150. It has a stated life of approximately 6,000 cycles after which it only holds 60% charge. Let’s be generous and assume your battery will take 8,000 full charge cycles equivalent. Each cycle of the US2000 is with 2.2kWh as it has a 90% DoD. So 1150/(8000*2.2) gives you 6.5c cost of extracting a unit from the battery. You pay 8c for it at the night rate, lose at least 5-10% in charge and discharge and AC/DC transform. So let’s say 1 unit out the battery actually cost you 8.8c. So in reality your cost of one unit from the battery is 15.3c You are not saving much after that. 1-2c if my assumptions are correct. Over its lifetime the battery will save you maybe €250 if used just to charge at night rate. Not a great return after 15+ years on an investment of 1150. If the battery only lasts the stated 6000 cycles your total cost per unit goes up to 17.5c. Pretty sure you can get a day rate cheaper than that.
A battery has a finite life. So every time you put energy into it or take energy out of it you are using up its life so you have to account for the cost.

garo

Northumberland, Yes if you charge and discharge in the middle of the capacity range LiIon batteries last longer. Google batteryuniversity for some nice graphs. In my calculations above I assume a 90% cycle so going from 100% to 10%. Pylontech is Lithium Iron Phosphate which tolerates 100% charge better than other Lithium chemistries.
If you go from 40% to 85% and back you do get more cycles but you get less usable energy. Each half cycle only gets you 1.08 KWh so if you get 16,000 cycles your cost per unit is still the same. 1150/(1.98*16000) is 6.6c

AidenL

garo wrote: »

Yes Unkel has it right. One Pylontech 2000 is costing you €1150. It has a stated life of approximately 6,000 cycles after which it only holds 60% charge. Let’s be generous and assume your battery will take 8,000 full charge cycles equivalent. Each cycle of the US2000 is with 2.2kWh as it has a 90% DoD. So 1150/(8000*2.2) gives you 6.5c cost of extracting a unit from the battery. You pay 8c for it at the night rate, lose at least 5-10% in charge and discharge and AC/DC transform. So let’s say 1 unit out the battery actually cost you 8.8c. So in reality your cost of one unit from the battery is 15.3c You are not saving much after that. 1-2c if my assumptions are correct. Over its lifetime the battery will save you maybe €250 if used just to charge at night rate. Not a great return after 15+ years on an investment of 1150. If the battery only lasts the stated 6000 cycles your total cost per unit goes up to 17.5c. Pretty sure you can get a day rate cheaper than that.
A battery has a finite life. So every time you put energy into it or take energy out of it you are using up its life so you have to account for the cost.

Is it fair to say it’s sensible to get a battery to avail,of the extra grant, but it should only be used to store free panel generated electricity then. And even then, it costs 6.5c, but offset by the additional grant?

garo

Yes even then it costs 6.5c per unit. At that rate you have a much quicker payback because that is substantially less than the day rate which you’d be paying for your evening usage which a battery would typically cover.

Note that if you get a battery set up you also have to fork out for a hybrid inverter which costs 5-800€ more than a normal inverter. On the other hand you get to claim up to €2400 extra in SEAI grants. So if you are getting 4kW of panels then it is a no-brainer to get a battery. I went for a small battery as it is a flat battery grant so you don’t get more for a larger battery. I’m hoping for some form of FiT or net metering or a substantial drop in battery prices in the coming years. If battery prices halved, I would add more in a heartbeat.

AidenL

garo wrote: »

Yes even then it costs 6.5c per unit. At that rate you have a much quicker payback because that is substantially less than the day rate which you’d be paying for your evening usage which a battery would typically cover.

Note that if you get a battery set up you also have to fork out for a hybrid inverter which costs 5-800€ more than a normal inverter. On the other hand you get to claim up to €2400 extra in SEAI grants. So if you are getting 4kW of panels then it is a no-brained to get a battery. I went for a small battery as it is a flat battery grant so you don’t get more for a larger battery. I’m hoping for some form of FiT or net metering or a substantial drop in battery prices in the coming years. If battery prices halved I would add more in a heartbeat.

I’m on that trail of a deal based on those specs.

I guess 6 kw of panels as opposed to 4 would be sensible if a fit appears? The panels are relatively cheap, and would cost more to bring installers back? Still use the small battery with the 6kw of panels?

unkel

The more panels, the better, AidenL. It costs very little extra to install 6kwp over 4kwp and you will reap the benefits forever after. Maybe not yet tomorrow if you only go for a small battery, but we are likely to get a FIT, you are likely to own an EV in the near future, we will all use more electricity and less fossil around the house and batteries will become cheaper. It is also a buffer against electricity becoming more expensive in future.

AidenL

unkel wrote: »

The more panels, the better, AidenL. It costs very little extra to install 6kwp over 4kwp and you will reap the benefits forever after. Maybe not yet tomorrow if you only go for a small battery, but we are likely to get a FIT, you are likely to own an EV in the near future, we will all use more electricity and less fossil around the house and batteries will become cheaper. It is also a buffer against electricity becoming more expensive in future.

I am going to retrofit a heat pump in spring also, so I won’t need the eddi either. More you guys explain it, the smaller battery makes a lot of sense.

garo

I went for 4.8kWp and would have gone for more if I had room. Go for the 6kWp and a 3.5kWh battery - if Pylontech. I was very tempted to add a second battery but you most likely will be better off waiting. In the meanwhile feel happy about your contribution to the environment.

PS: A few links I found useful:
1) Figure 5 on page 7 of this report shows how Australian electricity demand profile has changed with solar. That peak at 7pm is why I think a small battery isnot so bad after all despite the environmental cost. AEMO report. Also see attached image.
E/W will help but only to a point. Ultimately we need to store the excess solar energy generated during the day.
2) Types of Lithium Ion
3) How to prolong Li-Ion batteries

Cortina74

So upon further investigation:

8 panel install on a flat roof (orientation somewhat flexible).

8 panels @300Wp (or 225Wp at NOCT), 40V (or 30V nominal at NOCT), 9.7A (or 7.5A nominal at NOCT)
Divided into two strings which then connect parallel.
The calcs below assume the NOCT figures supplied by the panel manufacturer (rounded).

Strings x 2 (NOCT figures):
4 x 30 = 120V
4 x 7.5 = 7.5A
4 x 225 = 900W

Two strings wired in Parallel:
2 x 120 = 120V
2 x 7.5 = 15A
2 x 900 = 1800W

Hope my maths are correct!:o
So would this seem feasible on the 1.5kW Solis inverter (max input 1.8kW, max amps 11A, sort circuit amps 17.2A)?
If using a slightly different orientation for each of the strings (SE & SW) then the peak load could overlap and spread over a longer time period, thereby reducing the actual load on the inverter ???? I’m focusing mostly on the Amps part here it seems the Solis range is mostly 11A unless you go to a dual MPPT which can take two strings of 11A each. This would also bring the install cost right down for a DIY install.

Does anyone know if the NOCT panel figures would be more realistic than the STC figures when calculating for Dublin?

Thanks to unkel and air for getting me this far!

Cortina74

Actually on reflection of my own calcs above.
Would it actually be the most efficient in terms of power production?
With two differently orientated strings running parallel the less efficient string at any particular time of day would simply pull down the voltage of the more efficient string, no???
So the evening orientated string would operate at the voltage of the afternoon orientated string (I think )
Maybe a dual MPPT as per unkels set up would be best?
Just trying to save money but it might be a false economy.

Northumberland

It is a bright sunny morning here in Belturbet Co. Cavan, and my panels are churning out 2kW. But since my 5kW of batteries were already fully charged on the night tarrif, there is nowhere for this 2kW to go, expect as a donation to ESB. So, in addition to the good arguments made earlier by Unkel and others, paying even the cheaper night rate tariff to charge the battery which prevents it being charged in the morning for free makes no sense. I am changing my set-up now!

garo

2kW from 4.5kW of panels? That’s nice. What orientation do you have? My East facing 2.4kW are churning out 1.2 but the West facing one’s haven’t got going yet and only putting out 200W. My roof is also a relatively shallow angle.

air

Northumberland wrote: »

But since my 5kW of batteries were already fully charged on the night tarrif, there is nowhere for this 2kW to go, expect as a donation to ESB.

You might be able to use IFTTT or similar to vary the target percentage of the overnight battery charge based on the forecast perhaps?

unkel

I too saw over 2kW a day or two ago from my 3.6kW inverter (3.8kwp) when the sun came out. Quite surprised the PV is still producing better than I expected (coming into the first winter of my install)

garo

But total production is definitely down. In October my best day so far has been 12kWh. In Sep it was 19 and in Aug 22.5. Only got installed middle of August.

reklamos

Northumberland wrote: »

It is a bright sunny morning here in Belturbet Co. Cavan, and my panels are churning out 2kW. But since my 5kW of batteries were already fully charged on the night tarrif, there is nowhere for this 2kW to go, expect as a donation to ESB. So, in addition to the good arguments made earlier by Unkel and others, paying even the cheaper night rate tariff to charge the battery which prevents it being charged in the morning for free makes no sense. I am changing my set-up now!

To get most of use of the PV you need to adapt to it.
I check cloud coverage for next day and then again in the morning to see what is the best way to use all the power that will be generated. If I see that the day is going to be good I(tell wife) setup dish washer or washing machine or both on timer to use at the peak of generation. This work pretty well so far. The rest goes to battery or diverted to heat the water.

I do not have night meter so don't use to charged my 7kWh battery but If I had I would probably charge it 80% during night time. Also as someone mentioned the other option is to do some automation but that would very depend if inverter allows it.

air

air wrote: »

You would need detailed performance data on your proposed battery as well as an estimated usage pattern in order to model various usage scenarios.

From an independant tester.

air wrote: »

One thing in favour of night rate cycling is that batteries have a calendar lifetime as well as a cycle life so it may make a little more sense from that point of view to cycle them more while you have them.

Disagree. Not cycling a battery will live longer than cycling.
If cycling the battery at an increased delivered energy cost of night rate lecky on top of hardware investment then not only will you have a negative investment but a rather sizeable one.

air wrote: »

It also gives you a bit more protection against power cuts if you have an essential load setup as the battery will be fully charged more of the time.

Depends on the setup. A lot won't.
I can fit a back-up system for a couple hundred. Its off-grid, network connection regulations do not apply.

air wrote: »

All told though I'm not convinced it's worth the hassle, charging from excess PV that would be otherwise exported for free is a much better business proposition.

I understand it's not worth the hassle and negative return.
Using a battery is neutral to negative return compared to utiliy import.
Sizing & distributing our arrays according to load demand and profile is very worthwhile.

air

Sir Liamalot wrote: »

Disagree. Not cycling a battery will live longer than cycling.

I never argued the opposite, however the fact remains that lithium batteries have a finite calendar life. I have lithium packs from 2005 onwards and some have expired during storage after very few cycles. To a certain extent you may as well cycle them before they expire of natural causes!

Sir Liamalot wrote: »

I understand it's not worth the hassle and negative return.
Using a battery is neutral to negative return compared to utiliy import.
Sizing & distributing our arrays according to load demand and profile is very worthwhile.

While I agree I think you're overestimating the impact of distributing the arrays.
I have a 3 directional installation myself and it's definitely a great benefit, especially having production early in the morning and late into the evening.

However a battery is another level in terms of smoothing demand and reducing import. We frequently have cloudy weather which leads to very peaky production, demand is also very peaky by it's nature.
A battery really helps to bridge the gap between production and demand during the day while the solar is producing. Even a small battery is a big help in this regard.

AidenL

My head is melting. Spoke to a few installers today - prices are not cheap, I'll post details later.

Just wondering if you experts could cast your eye over both of these batteries and see which seem to have best specs please?

In general, for a Solax setup, looking at 4kw, 5kw investor, and 4.4kw battery at 10800 including VAT. , 7k nett.

6kw, same investor and battery, 13000 inc VAT, 9200 nett.

The Alpha ESS installer was around the same price.

Are Pylontech batteries to a similar standard as those on the attachments? They don't look as neat, being rack mounted. But do they perform as well?

j1mboj0nes

Anyone can recommend a Solar PV installer in Cork?



Got quoted today for €6160 after the grant applied, for 2.4Kw + inverter & iboost.



Seems a touch steep

garo

air wrote: »

However a battery is another level in terms of smoothing demand and reducing import. We frequently have cloudy weather which leads to very peaky production, demand is also very peaky by it's nature.
A battery really helps to bridge the gap between production and demand during the day while the solar is producing. Even a small battery is a big help in this regard.

This. A hundred times this!

garo

AidenL wrote: »

My head is melting. Spoke to a few installers today - prices are not cheap, I'll post details later.

Just wondering if you experts could cast your eye over both of these batteries and see which seem to have best specs please?

In general, for a Solax setup, looking at 4kw, 5kw investor, and 4.4kw battery at 10800 including VAT. , 7k nett.

6kw, same investor and battery, 13000 inc VAT, 9200 nett.

The Alpha ESS installer was around the same price.

Are Pylontech batteries to a similar standard as those on the attachments? They don't look as neat, being rack mounted. But do they perform as well?

Prices are ok though a touch on the higher side. It could also be a factor of how difficult your install is. I have no issue with the Pylontech but it is early days. I think Solax are also LFP. Solax batteries and inverters run on a higher voltage so lower current for some power so theoretically are more efficient.

garo

j1mboj0nes wrote: »

Anyone can recommend a Solar PV installer in Cork?



Got quoted today for €6160 after the grant applied, for 2.4Kw + inverter & iboost.

Seems a touch steep

That is very expensive. For that money you could almost get 4kW + battery setup.

j1mboj0nes

garo wrote: »

That is very expensive. For that money you could almost get 4kW + battery setup.

Yeah thought it was a bit ridiculous.

Any advice on how best to spend or what I could get for a budget of about €4000, with the assumption that FiT is going to be available in the next year or so

bunderoon

j1mboj0nes wrote: »

Yeah thought it was a bit ridiculous.

Any advice on how best to spend or what I could get for a budget of about €4000, with the assumption that FiT is going to be available in the next year or so

What's your annual electricity costs and is there anyone home during the day to benefit from the generation (if no battery). FIT price isn't going to be substantial in Ireland.

j1mboj0nes

bunderoon wrote: »

What's your annual electricity costs and is there anyone home during the day to benefit from the generation (if no battery). FIT price isn't going to be substantial in Ireland.

Average monthly bill for the last two years is €70. There's someone home 1 day during the week and both days at the weekend.

AidenL

garo wrote: »

Prices are ok though a touch on the higher side. It could also be a factor of how difficult your install is. I have no issue with the Pylontech but it is early days. I think Solax are also LFP. Solax batteries and inverters run on a higher voltage so lower current for some power so theoretically are more efficient.

I do have slates which were quoted as 500 extra over tiles.

So you'd think Solax would be a better bet?

bunderoon

j1mboj0nes wrote: »

Average monthly bill for the last two years is €70. There's someone home 1 day during the week and both days at the weekend.

That's not really much.
Say you spend 900 a year on power. Solar will, at best, reduce you bill by half if you get enough panels and change your usage patterns (washer,dryer&dishwasher when the sun is out)

450 per year leaves you with >12 years ROI. FIT would reduce it to ~8-9.

Do you have LED lights or A rated energy appliances? If not, it would be cheaper to go that route than the huge expense.

Just my 2cents.

KCross

Apart from solatricity.ie where else is a good source to direct buy Solar PV kits?

j1mboj0nes

bunderoon wrote: »

That's not really much.
Say you spend 900 a year on power. Solar will, at best, reduce you bill by half if you get enough panels and change your usage patterns (washer,dryer&dishwasher when the sun is out)

450 per year leaves you with >12 years ROI. FIT would reduce it to ~8-9.

Do you have LED lights or A rated energy appliances? If not, it would be cheaper to go that route than the huge expense.

Just my 2cents.

Yes to the LED lights and appliances. My reasoning is that I'm planning on getting an EV for my next car and I'll likely be working from home regularly next year.

Also I expect that the seai grant may be discontinued when the FIT comes in so now feels like the best time to get solar pv.

garo

Go for it. If you are planning to get an EV and work from home you should be able to utilize a lot of your solar power. I would call around and ask for quotes on both battery and non-battery setups. A battery set-up will probably be 6k at least. You could go for just panels but then you only get a grant for 2kW whereas with a battery you get a grant for 4kW + 1000 for the battery.
Your other option is to go for a self-install - you buy the equipment and hire roofers/electricians. If you have a simple install - e.g. a bungalow this may come in cheaper even without the grant.
Get a few quotes and come back on this thread. Also read through the thread to know what sort of questions you should be asking the installers when they come for site visits.

garo

AidenL wrote: »

I do have slates which were quoted as 500 extra over tiles.

So you'd think Solax would be a better bet?

I really don't know. I think the difference is marginal. Yes you have smaller current flowing which should mean lower resistive losses but if the distance between the inverter and batteries is small, it should be minimal difference. Solax triple power gives you a max output of 2.5kW which is what you would get if you had two 2.4kWh Pylontech batteries. A single one gets you ~1250W.

For slates that costs is ok. The 6kWp over 4kWp seems a bit high. 2200 for 6 more panels is a bit much. Especially as you say the inverter is the same. How much electricity do you use? Do you really need 6kW?

AidenL

garo wrote: »

I really don't know. I think the difference is marginal. Yes you have smaller current flowing which should mean lower resistive losses but if the distance between the inverter and batteries is small, it should be minimal difference. Solax triple power gives you a max output of 2.5kW which is what you would get if you had two 2.4kWh Pylontech batteries. A single one gets you ~1250W.

For slates that costs is ok. The 6kWp over 4kWp seems a bit high. 2200 for 6 more panels is a bit much. Especially as you say the inverter is the same. How much electricity do you use? Do you really need 6kW?

Yeah I think the upgrade to 6kw is a rip off.

I used around 12 units daytime and 5 overnight.

Northumberland

There was an exchange of views a week or so ago on this thread about how a regular Solis Hybrid inverter could continue to power some lights, internet, TV, phone charger, electric kettle maybe, in the event of a total mains power cut. Some said it simply could not be done, but the manufacturers 'blurb' states that it could. I am very pleased to say that after an afternoon of hard work, with the help of a great company technician working with me on Whatsapp, I got my system working perfectly. There is a separate 'off grid' output plug on the base of the inverter. The menu settings have to be changed and set 'just right'. But I now have a bank of three 13 amp ac sockets mounted on wall near the inverter which will continue to provide 230 volts supply, up to 2.4 kW approx in total, for as long as the sun shines or for as long as I have some charge left in my 2 Pylontech batteries. Those reading in Dublin who never experience power cuts might be wondering why I bothered. I live in a rural area of County Cavan and our mains power comes via an overhead cable through a nearby forest plantation - which is really hard to access by repair crews. Last winter, each of the major storms caused trees to fall on the line, and each time we were without power for hours at a time, once overnight, until the ESB crews could mobilise, find the breakage and repair it. ESB seem dis-inclined to re-route the overhead cable away from the forest, they think too small a number of people are affected and prefer just to fix it when it breaks. At least this winter, I am prepared and will not worry about power cuts at all. This is a great added benefit of a hybrid inverter and batteries of a kind that has the capability to do this, which for some reason the companies selling them do not advertise very much.

wexfordman2

Northumberland wrote: »

There was an exchange of views a week or so ago on this thread about how a regular Solis Hybrid inverter could continue to power some lights, internet, TV, phone charger, electric kettle maybe, in the event of a total mains power cut. Some said it simply could not be done, but the manufacturers 'blurb' states that it could. I am very pleased to say that after an afternoon of hard work, with the help of a great company technician working with me on Whatsapp, I got my system working perfectly. There is a separate 'off grid' output plug on the base of the inverter. The menu settings have to be changed and set 'just right'. But I now have a bank of three 13 amp ac sockets mounted on wall near the inverter which will continue to provide 230 volts supply, up to 2.4 kW approx in total, for as long as the sun shines or for as long as I have some charge left in my 2 Pylontech batteries. Those reading in Dublin who never experience power cuts might be wondering why I bothered. I live in a rural area of County Cavan and our mains power comes via an overhead cable through a nearby forest plantation - which is really hard to access by repair crews. Last winter, each of the major storms caused trees to fall on the line, and each time we were without power for hours at a time, once overnight, until the ESB crews could mobilise, find the breakage and repair it. ESB seem dis-inclined to re-route the overhead cable away from the forest, they think too small a number of people are affected and prefer just to fix it when it breaks. At least this winter, I am prepared and will not worry about power cuts at all. This is a great added benefit of a hybrid inverter and batteries of a kind that has the capability to do this, which for some reason the companies selling them do not advertise very much.

Nice work.

Quick query though, as my understanding that the requirement of an install under seai guidelines is that in the event of a power cut, obviously the mains us disconnected and you are left with your "essential load" circuit still running, but that also the dc input into the inverter is disconnected, so even if the solar is producing, you cannot charge your battery from it ?

Any chance you could post up a bit of how you wired your backup circuits ?

air

wexfordman2 wrote: »

Nice work.

Quick query though, as my understanding that the requirement of an install under seai guidelines is that in the event of a power cut, obviously the mains us disconnected and you are left with your "essential load" circuit still running, but that also the dc input into the inverter is disconnected, so even if the solar is producing, you cannot charge your battery from it ?

Any chance you could post up a bit of how you wired your backup circuits ?

I'm not familiar with the SEAI guidelines but an automatic DC disconnect would require an expensive contactor as well as separate mains failure sensing. I've never seen one used.

Northumberland

Look, based on my experience with long phone calls with SEAI Audit department last Friday, I would have to say, with respect, that even SEAI staff are not familiar with SEAI guidelines. My initial installation failed an audit inspection partly for the reasons that have been alluded to in the previous two posts. My installer did not install 'firemens shunts'. This has now been done. These are sort of relay things fitted in the roof space under the panels, and they only keep the DC connection from the panels down to the inverter connected so long as their is AC mains current. Once the AC mains is switched off at the distribution board, OR if there is a power cut, the DC supply is automatically isolated. This is apparently to protect fire fighters in the event of a house fire, they would not want to use their water hoses on the house or walk around if they feared high voltage DC current was running loose apparently.

So, thinking about this, I probably have to modify my previous post in which I said I can continue running my essntial loads from my batteries OR from the solar panels. I can only continue to run essential loads from the batteries at the moment I think, of course it should be possible, once the inverter is generating AC from the batteries, for that AC essential load circuit to be wired up to the 'firemans shunts' so that they again allow the DC to run, but I suppose that would contravene SEAI guidelines if they discovered it.