Another Solar Thread

Korojohnz

Evening all

I've had three quotes back from some providers recommended by Solar Sherpa, and I'm trying to get some feedback from people on the system, the equipment, battery sizing and of course the costs!

All three systems have 28 panels - 12 facing SW and 16 facing NE. Average daily use is around 35kw. 4 bedroom house in Surrey with pool (heated by gas) & hot tub. No a/c yet (but a possibility in the future) and GCH. No EV either (or plans to get one).

System 1 is a 28 panel AIKO-A530-MCE60Db array with a Goodwe GW10K-ET-20 and  3 x GW8.3-BAT-D-G20 batteries - £15k. Annual output - 10,201kwh

System 2 is a 28 panel Longi Hi-Mo lr7-54hvb-475m array with an EcoFlow OCEAN 2 Plus (Single-Phase) Hybrid Inverter 12kW and 5 x EcoFlow OCEAN 2 Battery - £16,900. Annual out - 9355 kwh

System 3 s a 28 panel Longi Hi-Mo lr7-54hvb-480m array with a Solax 1EX 8kw invertor a 4 x TP-HS50E batteries - £15,917. Annuals output 9,846 kwh

On the face of it the Ecoflow batteries have 66% more cycles (10k vs 6k) against the Solax, and 25% more than the Goodwe, but £2k more expensive.

Is the Ecoflow system that much better?

I'm trying to work out if 20kwh or 25kwh is the better battery - I thought I had it nailed until someone mentioned needing to take the shortening battery life on the dynamic import/export tariffs into account, and how much shorter that life could be before the battery needs replacing and balancing that with what I'd get from exporting.

I've not really looked into any Tesla Powerwall systems - are they really worth the premium? Another other suggestions for hardware? One installer poo-poo'd the Eurener panels saying they'd had some discolouration issues.

I'm also quite interested in the way that different contractors seem to have different output calcs for what is largely the same system - System one with the Ecoflow is 10,201, whereas system 3 with the Goodwe kit is 9,848 kwh. Do they have some flex in the calculation process that allows tweaking of the output to fit whatever system they want to promote?

Apologies for the rant - hopefully there's enough for some with more knowledge than me (that's pretty much everyone) to give me some independent guidance!

happyretiree

I’m blinded by your science and I don’t have solar panels. A friend advised me to get more battery than recommended because if you find you need to buy additional battery after the installation you’ll have to pay VAT. He was in that position.

Qyburn

https://forums.moneysavingexpert.com/discussion/comment/82116191#Comment_82116191

At least until next March, a battery installation is 0% VAT. If you just buy the battery, don't have it installed, then it's 20% VAT.

Korojohnz

https://forums.moneysavingexpert.com/discussion/comment/82116191#Comment_82116191

Thanks - and apologies! I've been trying to find out much about the Goodwe support in the UK, but that doesn't sound great - does anyone have much experience of Ecotherm?

QrizB

Welcome to the forum.

Aiko and Longi panels are from the budget end of things. EcoFlow, Goodew and Solax are all budget-to-mid-market. I think @Reed_Richards has a Goodwe inverter coupled to a LG battery; he might be able to give you some feedback on those.

I think you might also want to drop a DM to @Screwdriva and see what he can suggest for you. He favours Eurener panels and Tesla batteries; it'll probably cost a little more than the £15-16k you've been quoted but it'll qualify you for more favourable tariffs.

Reed_Richards

I do have a Goodwe inverter. It has been running since March 2019. The WiFi module failed two years ago but I was able to replace this under warranty with a module supporting a wired connection . Otherwise it has worked well. Goodwe have online tech support but they can be slow to respond. They were able to tell me of a local company that works with Goodwe equipment that I could call on, should I ever need to. Goodwe seems to be a popular brand in Australia; much less common here.

I would offer the opinion that continuing support from the company that installs your system is possibly more important than their choice of equipment.

Screwdriva

I would not proceed with any of those quotes (I'll get to why a bit later). Here is one I would not hesitate to recommend:

28 X Eurener 515W bifacial panels. (30 year product/ performance warranty)

1 X Tesla PW3 with Gateway 2. 11 KW built in inverter. 13.5KW of storage. (10 year unit replacement warranty. Unlimited cycles)

~£14K installed. 10 year workmanship warranty. Bird Netting and G99 application all included.

A few thoughts:

1) Not sure if you are bothered by forced (slave) labour from some Chinese owned brands but this research paper shades Longi panels bright red. (Aiko didn't market solar panels when the paper was published).

2) Nothing quoted above can hold a candle to the cold weather performance, safety, software, aftersales and engineering of the Tesla PW3

3) Check the workmanship warranty duration. I would not recommend any installer with < 10 years, to ensure your system has paid for itself well before service labour costs are a consideration down the road.

4) Check the battery warranty fine print. There are loads of hidden "get out of jail" clauses.

5) Check the charge/ discharge capability for each battery inverter system. 28 panels = 14.3KWp. No point in having all that power if the battery inverter can only export a fraction of it to the grid. The Tesla PW3 can export upto 11.04KWh, which is why I recommend it for larger arrays as a default.

6) If you really can't cut your electricity import down a bit, the Tesla expansion pack adds another 13.5KW of storage for ~£4K and increases the system's charge rate from 5KW to 8KW.

7) Following the surge in demand post Iran war, Eurener did have a batch of discolored panels but that has since been rectified.

8) Following the bankruptcy of GivEnergy, I try to recommend brands that are well capitalized and that will survive other boom/ bust cycle.

Hope this helps give you perspective and a steer!

Korojohnz

https://forums.moneysavingexpert.com/discussion/comment/82117319#Comment_82117319

Thanks @QrizB. When I do a google search for "best UK PV panels" the Longi and the Aiko gets mentions - what would you suggest as alternatives?

Korojohnz

https://forums.moneysavingexpert.com/discussion/comment/82117396#Comment_82117396

Thanks @Screwdriva - much appreciated!

Aside from the moral aspect, what makes the Eurener a better bet than the other two? I did mention Eurener to a couple of the contractors - one was ambivalent whilst the other mentioned the discolouration issue. I also will struggle to get 28 of the larger panels on my roof I think.

Are you able to point me in the direction of the contractor who would supply and install the system you mentioned please?

I was told one of the issues with exporting is the impact on battery life - 2 cycles a day effectively halving the point at which performance drops off.

At the risk of sounding rude (which I'm not, just curious), can I ask why you don't have the PW3 in your sig?

QrizB

… what would you suggest as alternatives?

My rooftop panels are Sharp, but I don't think Sharp makes panels any more.

See Screwdriva's reply above re. panels. He has a short list of preferred brands with decent ethics and quality; see this post from earlier this year.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82117408#Comment_82117408

I have no data to claim that Aiko or Longi are better or worse. I just know that Eurener has been made in Spain since 1997 and are bound by EU laws, which gives me greater comfort. I have helped dozens of homeowners with them and the results have been better than expected.

I don't have a PW3 because my annual consumption of electricity is 1550 KWh. That does not mean I do not turn slightly green whenever someone has one installed. It's such a fantastic bit of kit!