PV Panel "upgrade"

paulypost

We’re at CF38 with 12 x 250 LG black panels (I mention the colour ‘cos my wife chose them!)

Because of the shape of the roof they are wired in two arrays/strings. One slightly off south, the other south-west. Have been getting avg 2200 Kwh per year since Dec 2011. Got in just before the FITS rate went down. So RoI of 11%+ pa on an investment of £9k is one of the best I’ve made in the past difficult decade.

The original ‘project’ (I am retired so I need one every so often – between real jobs) came about as a result of receiving details on a routine Tesla e-mail of their PowerWall 2. After an hour or two the sales adviser/rep and I came to the conclusion that storage was not a financially viable proposition at £8k+ (at home during the day and using a lot of the generated power).

Having examined my generation numbers in detail, he showed me that I could/should be getting better returns compared to SAP figures by about 8% caused by some roof shading and also potentially because of the panels being wired as a string rather than in parallel.

The other spectre also raised was the life of the inverter (Sunny Boy) which is already out of warranty and the inability to track a problem panel if one failed, with all the hassle and cost of getting it replaced and claiming on warranty. And with one defective a whole string’s output would be reduced of course.

So, to get to the point, I have committed to a £4k ‘investment’ in a so-called upgrade.

This includes:

a new Solar Edge inverter with a 20-year warranty,

individual SE optimisers on each panel with a 25-year warranty,

on-line monitoring of each panel plus follow-up with LG if one goes wrong.

I suppose the USP which attracted me most was the individual monitoring to which I will have access via an app, as well as the peace of mind of longer term warranties and someone to call if anything goes wrong. The installer is Solar Plants of Port Talbot who seem to be well established having received business awards, Which? recognition, and many TrustPilot favourable comments (I know – pinch of salt?). And they are a preferred supplier of the Tesla Power Wall 2 – remember that from above?

Any comments/advice would be very welcome. Thanks in advance

ASavvyBuyer

That seems very expensive for just a new inverter & SE optimisers.

You could virtually get a whole new system, including new panels and installation for about £4-5k.

Why not wait until your inverter fails and then get a new SE inverter & optimisers from another supplier at a lot less cost?

Cardew

Are the 20 and 25 year warranties backed by an insurance policy from a reputable company?

I have little faith in these long term warranties for any product - not just solar.

Already on this forum there are many tales of woe from people who have found that their warranties are worthless as companies have gone out of business. Even if the inverter/panel company themselves will honour a warranty, who will diagnose, remove and dispatch part and refit new item.

paulypost

Thanks ASavvyBuyer - take your point re cost but a whole new installation would result in reduction of FITTS rate. Getting 50p+ now because of original installation date of Dec 2011


Thanks Cardew - good point re insured warranty. Solar Plants have HIES which at least insures the workmanship warranty of 10 years. I guess the longer warranties are less reliable. But maybe in 20 years time my own warranty may well have run out?

gefnew

Hi paulypost
If the shading is only on certain panels during the day, there are optomisers that can be fitted just to individual panels.
This depends on how easy it is to get to them,and or if you are needing any work to be done on the roof.here is a link to them.
https://www.tigoenergy.com/about-tigo/press-releases/66/
regards
gefnew

ajbell

Deal with the shade problem itself?.

pinnks

I agree with the comments from the others and would question whether it is ever worth upgrading to gain even 20% increase in production. Your 3kWp system might manage an extra 300kWh making 2,500 per year with the upgrade. At 50p per kWh that's £150 per year, or over 25 years to break even (ignoring inflation).

I too have a shading issue on my smaller array and thought long and hard about going SE (or some other option). I reckon that the shading costs me about 3kWh per day on good days in summer, not worth a candle in winter, so perhaps 100 days at 3kWh or 300kWh per year lost. At my FiT rate that is about £55, so even if the upgrade cost "only" £1,000 it would take 20 years to repay the investment.

Although I wish I knew then what I know now, there are better things to do with £1,000 and certainly better things to do with £4,000.

paulypost

Thanks for the additional comments/views.


I mentioned shading only in passing and, as it’s caused by the (saddle) shape of the roof and is a problem more when the sun is low in winter and early in the day, no issue really and not possible to solve it.
What ‘clinched the deal’ for me was the additional warranties plus the panel monitoring and support in any future claim against LG if one of the panels goes down. Of course, additional generation will be a bonus, but will not give an early breakeven. Having said that, £4k at 0.5% interest would earn £20pa or max £100 in a no access long term fixed account. So if I get more than that in additional FITS I shall be doing well?

Exiled_Tyke

paulypost wrote: »

Thanks for the additional comments/views.


I mentioned shading only in passing and, as it’s caused by the (saddle) shape of the roof and is a problem more when the sun is low in winter and early in the day, no issue really and not possible to solve it.
What ‘clinched the deal’ for me was the additional warranties plus the panel monitoring and support in any future claim against LG if one of the panels goes down. Of course, additional generation will be a bonus, but will not give an early breakeven. Having said that, £4k at 0.5% interest would earn £20pa or max £100 in a no access long term fixed account. So if I get more than that in additional FITS I shall be doing well?

Err no actually. Unless I'm missing something your calculations are out. You are comparing and investment where you lose your initial capital to a savings account where you get interest back as well as your initial investment. I can't see this one stacking up financially.

ASavvyBuyer

paulypost wrote: »

Thanks for the additional comments/views.


I mentioned shading only in passing and, as it’s caused by the (saddle) shape of the roof and is a problem more when the sun is low in winter and early in the day, no issue really and not possible to solve it.
What ‘clinched the deal’ for me was the additional warranties plus the panel monitoring and support in any future claim against LG if one of the panels goes down. Of course, additional generation will be a bonus, but will not give an early breakeven. Having said that, £4k at 0.5% interest would earn £20pa or max £100 in a no access long term fixed account. So if I get more than that in additional FITS I shall be doing well?

£4,000 for a new Solaredge Inverter & Power Optimisers still seems a lot. The Optimisers come with a 25 year warranty and a new Solaredge Inverter would have at least 10 years warranty included, and the online monitoring comes as standard with Solaredge.

Back in 2015, we were quoted £1,140 + VAT for that part of our install. So at least £2.5k more than that for the upgrade :eek:

BTW, £4,000 in a good interest paying current account (with instant access) would pay at least £100/year. (Take a look at the Banking & Savings forums on here). And you would still have your £4k available to pay for any repairs (if needed in the future).

Cardew

Exiled_Tyke wrote: »

Err no actually. Unless I'm missing something your calculations are out. You are comparing an investment where you lose your initial capital to a savings account where you get interest back as well as your initial investment. I can't see this one stacking up financially.

Spot on!

If anyone wants to give me £4,000 I will set up a legally binding agreement which will guarantee paying them £100 a year for 20 years. To make it a killer deal they will get Nectar points!