PV & battery quote, Advice & comments please.

Rasb77

Good Morning Moneysavers,

Before I start, I would like to say although I only joined the Fourm today, I have been a long time lurker in the background and have been greatly impressed by your knowledge and helpfulness on all things PV & home energy related.

I have been thinking of adding PV to my house for the last few years and have several quotes in the past so have a good idea of what will fit and prices ( the most recent quotes were earlier this year ) I have now had a quote from the Sussex Solar Together scheme which seems to be very good but not too good to be true.

The installation company is Infinity Renewables based here in Sussex, looking online they seem ok with the usual reviews ect. Any opinions on them?
Solar together seems to be a group purchase scheme using volume to drive down prices so again any opinion on them?

My details..
Living on the South coast near Brighton.
Electricity consumption was an average of 6,000kWh P.A over the last few years but I expect this to rise to 10,000kWh P.A or more going forward due to now owning a 40kWh Nissan Leaf and a hot tub in the garden.
We currently are on Octopus Go @14.4p & 5p until the new year so who knows how much that will increase to next year. But it will go up a lot! 
Currently use gas for CH but the boiler is now 20 years old so maybe we will go to a heat pump in the future, costs depending.

Quote..
20 x 365w JA Solar all black panels fitted on 2 roof slopes ( approx 12 East and 8 West, My guess, not theirs but based on previous quotes) Total peak output 7.3 kW.
Growatt inverter ( size not specified yet but expect 5 or 6kW )
All fitting ect inc
£6,914    at just under £1 per watt installed cost

9kWh of Growatt battery storage ( exact model not yet specified ) 
£3,301    at  £367 per kWh installed cost

Total is £10,215

This all seems very good to me but not so cheap as to be unrealistic.
So over to you with you thoughts please.

Rasb.

Verdigris

The kWp figure is a bit irrelevant, although the installed price looks right. You need the projected kWh/annum to calculate the ROI, although E/W split, on the south coast, should be OK.

The battery price, on the face of it, looks to be in the right ballpark. However, the useful storage depends on the DOD (depth of discharge) available. Growatt rings an alarm bell with me. I think it was inverters, in the case I'm thinking of, where the specification looked OK on the face of it but the inverter was so slow to respond that a lot of potential energy was lost. A good look around the internet would be in order to check the exact model proposed.

Rasb77

Verdigris said:

The kWp figure is a bit irrelevant, although the installed price looks right. You need the projected kWh/annum to calculate the ROI, although E/W split, on the south coast, should be OK.

The battery price, on the face of it, looks to be in the right ballpark. However, the useful storage depends on the DOD (depth of discharge) available. Growatt rings an alarm bell with me. I think it was inverters, in the case I'm thinking of, where the specification looked OK on the face of it but the inverter was so slow to respond that a lot of potential energy was lost. A good look around the internet would be in order to check the exact model proposed.

Thanks,
Their price is based off a few general details I have supplied. I can play around with PVgis to get exact figures and have several different sets of data already from earlier quotes.
I am quite happy to check their quoted figures and see if it differs from that. 

Battery specs from Growatt show its probably 3x3kWh units with a discharge rate of 1.6kw but I can get 1 x 6.5kWh battery with discharge of 3.3kW with 94% DOD which would probably suit me better as we cook all electric so need the higher kW output and would save about £1000 on the install cost.

ispookie666

With a split install you probably will need two strings.  
The price looks good, no idea about how many inverter and quality of inverter! 

ggmf

We too registered our interest with the Sussex Solar Together scheme, we are on the south coast, the scheme chosen installer (not the same as has been suggested for Rasb77's) is suggesting:

8 x 365w JA Solar (I believe we can get 10 panels installed),
SoFar inverter
I'll probably need Optimisers due to shading from a large ariel (either Solaredge of Tigo are recommended)
£4245 @ £1.45/w fitted, we will need to add £300 for the mesh to stop the flying rats from moving from other near installs to under ours, if we go ahead!

Our annual consumption is 4250kWh
PVGIS suggest 3251.33kWh might be possible for the 8 panels specified.

Reading through this forum, I believe this price is high, any thoughts and suggestion please on the costs and the equipment specified?

I would probably look at adding a battery into the solution, these are available at 3.2kWh, 6.4kWh and 9.6kWh with a SoFar ME3000SP storage inverter.

QrizB

ggmf said:

Reading through this forum, I believe this price is high, any thoughts and suggestion please on the costs and the equipment specified?

One immediate thought - is the aerial yours? It might be cheaper to move it, rather than fit optimisers.

ggmf

The aerial is ours but difficult to relocate. The shadow will move across the bottom 4 panels (late'ish afternoon), the panels will be in 2 banks of 4 (if we go for 8).

rjpearce

@ggmf I am looking at buying a Growatt system very similar to yours.

How is your system performing?
Are you happy with it?
Have you been able to charge the batteries at specific times to take advantage of Octopus Go?
Do you know if it directly supports Octopus Agile and Octopus Outgoing?

Thanks

ggmf

@rjpearce
1. System is now performing as I had hoped, we had some issues with the installed Tigo solution where random panels were being 'Shutdown' and placed into 'Safe' mode. Our installation has 2 strings, on one of the strings there is 4 panels,  so when one or more of these panels was being shutdown, that string produced no kw's as there was insufficient voltage to power the 2'nd MPPT input. The problem is now resolved, with no help from the company we ordered from or their sub-contacted installer (who are clueless).
2. Yes and No. It's now performing as I was expecting, though we are learning to load shift our usage when solar is available. I'm a bit data geeky, I want to know how each part of our installation is performing, I want to be able to access the base data from our installation so that I can analyse and compare performance over the coming years and also to be able to spot any potential issues. The Tigo installation both caused and highlighted that there was a problem, so in a way that was sort of helpful. I want data from my Growatt, as other users on here will agree, getting hold of that data is currently not available. I'd hoped to be able to take the RS485 data output from the Growatt and record that via the Tigo CCA, but that is not proving easy. The Growatt inverter is clearly sending the data that I'm after to their reporting server, you just cannot access it. If you are after data so that you can review your system, ask you installer to evidence data outputs. In my experience Growatt Support have been "a challenge".
3. We are not with Octopus and do not own an EV and hence are unable to sign up to Go or Agile, but yes you can set the inverter to take advantage of such flexible plans and charge the battery. (maybe the suppliers should be offering such flexible plans to us with batteries but no EV or indeed everybody so high usage items can be run overnight, seems a little discriminatory).
4. Not as far as I'm aware, but could be wrong on that, sorry.

Hope that helps.