Solar Quote-Opinions?

philng

Still very unsure of whether its worth while getting Solar. Annual usage only 2500Kwh but considering an EV which would take that to min 4000kwh.

Had following Quote any views on cost & quality of equipment would be appreciated?

11 Longi Longi 430W panels
Fox ESS EPS 5.18kw battery
Fox ESS H1 3.7kw Inverter
Emlite Meter

Total 4,73 Kw system

Cost £7595

Had another quote with smaller system nearly £10k with a different Co

I am unsure the benefits of this system & what pay back period would be.

Screwdriva

Solar definitely does make financial sense but a battery really only starts to make sense well above 4000 kWh per year. Given that you can charge the EV during a cheap nighttime rate, just like a battery, I would suggest you:

1) Skip the battery entirely and sell your excess Solar energy to the grid via Octopus Flux.
2) Fill your roof's South/ West/ East aspects with as many panels as possible. 
3) Invest in a quality system with long warranties and good aftersales (Longi/ Fox are extremely low end brands with very spotty reputations). 

For your perspective, this is the most recent comparable quote I've seen from the installers I use:

11 X Sharp 430W panels (25/30 year guarantee)
11 X SolarEdge optimizers (25 year warranty)
  1 X SolarEdge 5kW inverter (20 year warranty)
  1 X Bird netting

£5800 installed. Hope this helps! 

 

philng

Screwdriva said:

Solar definitely does make financial sense but a battery really only starts to make sense well above 4000 kWh per year. Given that you can charge the EV during a cheap nighttime rate, just like a battery, I would suggest you:

1) Skip the battery entirely and sell your excess Solar energy to the grid via Octopus Flux.
2) Fill your roof's South/ West/ East aspects with as many panels as possible. 
3) Invest in a quality system with long warranties and good aftersales (Longi/ Fox are extremely low end brands with very spotty reputations). 

For your perspective, this is the most recent comparable quote I've seen from the installers I use:

11 X Sharp 430W panels (25/30 year guarantee)
11 X SolarEdge optimizers (25 year warranty)
  1 X SolarEdge 5kW inverter (20 year warranty)
  1 X Bird netting

£5800 installed. Hope this helps! 

 

Thanks for your prompt reply. I was hoping you would respond. Looking further in to my quote the Warranty seems short 25 years on panels but looks like just 10 on Battery & 5 on Inverter.

Do I need a 5 Kw Inverter?

I live in Cheshire in North West and have South to South West facing rear roof. I think 11 panels is max for space.

How do I get a quote like you have stated with long warranties?

FlorayG

Get several quotes from different companies and ask all the questions. IN the end I went with the company that could either answer my questions or, for those they couldn't answer, they told me WHY they couldn't answer them. Look up the panels and equipment each offers you after they have left and see how they compare.
I don't think anyone can tell you if it's worth having - every person is different and their requirements differ.this summer I've sold so much electricity to the grid I have enough credit to run my gas central heating all next winter 

Reed_Richards

Screwdriva said:

Solar definitely does make financial sense but a battery really only starts to make sense well above 4000 kWh per year. Given that you can charge the EV during a cheap nighttime rate, just like a battery, I would suggest you:....

 

Well I would suggest you get a battery which you also charge overnight at a cheap rate in winter, at least charge enough to see you through the morning until you get some solar power.  It's difficult to know what would suit any individual best and I don't think it is a simple as a single criterion such as 4000 kWh per year.

Exiled_Tyke

Reed_Richards said:

Screwdriva said:

Solar definitely does make financial sense but a battery really only starts to make sense well above 4000 kWh per year. Given that you can charge the EV during a cheap nighttime rate, just like a battery, I would suggest you:....

 

Well I would suggest you get a battery which you also charge overnight at a cheap rate in winter, at least charge enough to see you through the morning until you get some solar power.  It's difficult to know what would suit any individual best and I don't think it is a simple as a single criterion such as 4000 kWh per year.

I'm with RR on  this.  I get barely any PV in Dec and January and so filling the battery (at 7p/kWh) is a great cost saving benefit for me.   

Also you should have an inverter with less capacity than the panels.  Smaller inverters are more efficient than big ones and you will find there are only limited times when your panels produce more than the inverter can handle (and so clipping will take place). It's usual to have an inverter of around 70-80% of panel capacity. However if the panels are split across more than one orientation (say East and West) then an even smaller inverter may suffice.  

Finally pay-back is a meaningless calculation for appraisal purposes.  Ideally an NPV or IRR calculation should be used which also considers changes in electricity prices.   There is also the risk (though less than it used to be) that the inverter will need replacing somewhere down the line as they haven't had the same lifespans as the rest of the equipment.   

Screwdriva

Reed_Richards said:

Well I would suggest you get a battery which you also charge overnight at a cheap rate in winter, at least charge enough to see you through the morning until you get some solar power.  It's difficult to know what would suit any individual best and I don't think it is a simple as a single criterion such as 4000 kWh per year.

While 4K kWh a year is definitely an approximate threshold which can vary +/- 5%, there are few scenarios that override hard numbers when calculating payback on a battery, regardless of sentiment. If OP suffers frequent blackouts or plans to install a heat pump in the near future, then an argument can be made in favour of a battery despite the low'ish consumption. 

The desire to charge the battery overnight does not negate the high capital cost or degradation of a home battery, relative to exporting via a lucrative PV tariff. 

philng said:

Thanks for your prompt reply. I was hoping you would respond. Looking further in to my quote the Warranty seems short 25 years on panels but looks like just 10 on Battery & 5 on Inverter.

Do I need a 5 Kw Inverter?

It's a pleasure to be able to help fellow MSE members! The inverter is a "wear and tear" item and that's why I always recommend purchasing from solid manufacturers with good reputations and warranty coverage. Fox offers few of those traits.

On a South/ SW aspect roof with 11 panels, a 4.7kW system will clip with a 3.7kW inverter. A 5kW inverter will prevent clipping losses. The incremental cost between the two inverter sizes is negligible. The reason dodgy installers don't quote for the larger inverter is because it involves additional paperwork (G99 application) which the installer must submit to the DNO. 

Exiled_Tyke

Screwdriva said:

On a South/ SW aspect roof with 11 panels, a 4.7kW system will clip with a 3.7kW inverter. A 5kW inverter will prevent clipping losses. The incremental cost between the two inverter sizes is negligible. The reason dodgy installers don't quote for the larger inverter is because it involves additional paperwork (G99 application) which the installer must submit to the DNO. 

I can't find it now which is a shame as I should have saved the link.  Some time ago I found a commercial PV operation which put plenty of figures in their annual report.  It is there that I got the recommendation for the 70-80% figure being the optimum for  panel kWp ratio to inverter.   My 3.3kwp panels haven't yet managed to clip my 3kW inverter (although it has gone over the 3kW mark occasionally).  When my installer told me they were 'downsizing' the inverter I was initially horrified but with research have come to the conclusion that it's the  most efficient decision.   

I'd definitely look for something more reputable than the brands mentioned although can't see the need for the cost of  Solar Edge unless there is significant shading or more than two aspects.  

Numbers on batteries do get complicated according to circumstances.  It works well for me because of the way the old FIT worked which is no longer relevant.  What is very encouraging though is that degradation has not been as bad as predicted and financially it has worked out far better than expected with the increases in electricity costs.  

One further point is that batteries don't usually help with blackouts. A system that does this is more expensive.  The issue being is that it needs to fully isolate itself from the grid to prevent discharge (presumably while network repairs are taking place).  Most battery systems  will shut down completely during a blackout although some do have a separate outlet to run appliances on.  

Screwdriva

Exiled_Tyke said:

I can't find it now which is a shame as I should have saved the link.  Some time ago I found a commercial PV operation which put plenty of figures in their annual report.  It is there that I got the recommendation for the 70-80% figure being the optimum for  panel kWp ratio to inverter.   My 3.3kwp panels haven't yet managed to clip my 3kW inverter (although it has gone over the 3kW mark occasionally).  When my installer told me they were 'downsizing' the inverter I was initially horrified but with research have come to the conclusion that it's the  most efficient decision.   

Downsizing inverter capacity is sensible but depends on several factors (aspect/ # of aspects being the primary). South facing aspects should be downsized by ~10%. E/W or triple aspects to greater amount.  In OPs case, the ideal would have been a 4.3 kW inverter but sadly no such inverter size exists. Rather than sacrifice the additional Watts generated by going with a 3.68kW inverter, my recommendation to upsize the inverter is to allow OP to capitalize on the every bit of their system's performance, especially given the negligible price difference between inverter sizes (~£100). 

I maintain that this was not quoted for because of the additional work installers have to go through for a G99 application. 

Exiled_Tyke said:

I'd definitely look for something more reputable than the brands mentioned although can't see the need for the cost of  Solar Edge unless there is significant shading or more than two aspects.  

In my experience, the SolarEdge system remains the best bang for the buck. Even as recently as this month, a MSE forum member I had helped with their installation had an inverter unexpectedly fail under warranty (2 out of 155+). SolarEdge diagnosed and then dispatched a replacement, which arrived at their residence within 72 hours, and it was up and running within 8 days. I have only seen comparable aftersales support from Enphase, Fronius and Victron. Then there's the panel level performance monitoring, the protection from panel fires and disproportionate panel degradation....

Exiled_Tyke said:

One further point is that batteries don't usually help with blackouts. A system that does this is more expensive.  The issue being is that it needs to fully isolate itself from the grid to prevent discharge (presumably while network repairs are taking place).  Most battery systems  will shut down completely during a blackout although some do have a separate outlet to run appliances on.  

You are correct. The Powerwall and All in One are the go to battery recommendations for blackout sufferers. That said, several battery brands can power dedicated circuits during blackouts, which is what I believe you were also stating. 

Exiled_Tyke

Sadly I seem to be the exception with Solar Edge. I had an optimiser fail but they insisted that it was a panel failure and not their component. It took repeated visits and costs to resolve.  They supplied the optimiser (eventually) but not the installers multiple costs of getting on my roof.   

Screwdriva

Exiled_Tyke said:

Sadly I seem to be the exception with Solar Edge. I had an optimiser fail but they insisted that it was a panel failure and not their component. It took repeated visits and costs to resolve.  They supplied the optimiser (eventually) but not the installers multiple costs of getting on my roof.   

That is wrong on your installer's part. The way it works with the 4 installers I use is that SolarEdge supplies the replacement part and their workmanship warranty (10 years typically) covers the replacement labour.