New to Solar PV and getting quotes

Exiled_Tyke

mparter said:

Finally got a quote through today. This is for a 12 x JA 380W panels, Huawei 5kw inverter and Huawei 10kWh battery for just under £11k. Anybody have any experience of the Huawei kit? Does the price seem reasonable?

This seems expensive to me.    My 6.3kWh battery cost me £3k installed.   With a (slightly ambitious) target of £1k per kW I'd be looking for £10 absolute maximum for this. I'm also very suspicious of  having a 5kW inverter.  With 4.5kW of panels I'd stick to a 3.6kW inverter and save any DNO bother - as with your previous quote.  There won't be many occasions that the panels produce more than 3.6kW and it will be more efficient on lower production days to go with the small inverter.   

And as Martyn suggests - I love the benefits of my battery but it really does not make economic sense. 

Solarchaser

I'd say the price is over what I'd expect, and I'm not sure the inverter being specced for over the panel output is a good thing.
I didn't know Huawei did inverters, nor batteries to be honest.

I wonder if it's worth going back to them and asking for a quote with same panels, but a 3.6kw inverter and no battery, should be more like 4-4.5k imo

[Deleted User]

My advice, FWiW, get as much solar as your roof can support and you can afford. On a cloudy August afternoon, my 7kWp array is producing 700Watts: 200Watts is supporting my home baseload and the rest is being diverted to my HW immersion heater. Roll forward to December: based on last year, I could be looking at a daily output of 350Whs on a bad day ranging to 10.6kWhs on a good day. To charge my EV from solar only, I need at least 1.3kWs of excess solar. That is often a challenge. Clearly, a battery changes everything but a large battery isn’t a cheap option. I have a PW2 (13.5kWhs). Even when the battery takes up the slack, I am still looking at taking 800kWhs/year from the Grid and putting 2200kWhs/year back.

mparter

Solarchaser said:

I'd say the price is over what I'd expect, and I'm not sure the inverter being specced for over the panel output is a good thing.
I didn't know Huawei did inverters, nor batteries to be honest.

I wonder if it's worth going back to them and asking for a quote with same panels, but a 3.6kw inverter and no battery, should be more like 4-4.5k imo

I have a quote from someone for solar only for £4.5k

[Deleted User] said:

My advice, FWiW, get as much solar as your roof can support and you can afford. On a cloudy August afternoon, my 7kWp array is producing 700Watts: 200Watts is supporting my home baseload and the rest is being diverted to my HW immersion heater. Roll forward to December: based on last year, I could be looking at a daily output of 350Whs on a bad day ranging to 10.6kWhs on a good day. To charge my EV from solar only, I need at least 1.3kWs of excess solar. That is often a challenge. Clearly, a battery changes everything but a large battery isn’t a cheap option. I have a PW2 (13.5kWhs). Even when the battery takes up the slack, I am still looking at taking 800kWhs/year from the Grid and putting 2200kWhs/year back.

Unfortunately I only have a combi boiler so don't have a water tank.

Solarchaser

In your situation, diverting to a hot water tank wouldn't be cost effective anyway.
It works for those of us on deemed export, but when you can actually be paid 5p for export, vs buying gas at 3p, it still makes sense to export.

Your quote for solar only, what size was the array and what size was the inverter?
If its 4kw+ array and a 3.6kw inverter then to be honest that's probably the best return on investment. 

You don't use enough electricity to get a good roi with a battery.
And based on your two quotes, you would be paying £6.5k for a 10kwh battery, it's not horrible, but it's not great either.

Usually pylontech batteries which are 2.4kwh (90%useable) are available for £700-750, they dont seem to be right now, but if we take that as the "normal" price.
A lux or sofar ac inverter is usually around £750 also.
So generally the 4 pylontech batteries would be £3k and then an additional £750 for an ac inverter, so £3750
At those figures it would be possible for you to get a maybe 15 year payback, but at £6.5k you are almost double that.

I'm unsure why the battery prices have jumped up right now, but I personally don't see how you can make the batteries work to give you a decent return on your investment at your lower energy usage and the higher price for the system, especially when you divert the excess solar into your car for the most part.

mparter

Solarchaser said:

In your situation, diverting to a hot water tank wouldn't be cost effective anyway.
It works for those of us on deemed export, but when you can actually be paid 5p for export, vs buying gas at 3p, it still makes sense to export.

Your quote for solar only, what size was the array and what size was the inverter?
If its 4kw+ array and a 3.6kw inverter then to be honest that's probably the best return on investment. 

You don't use enough electricity to get a good roi with a battery.
And based on your two quotes, you would be paying £6.5k for a 10kwh battery, it's not horrible, but it's not great either.

Usually pylontech batteries which are 2.4kwh (90%useable) are available for £700-750, they dont seem to be right now, but if we take that as the "normal" price.
A lux or sofar ac inverter is usually around £750 also.
So generally the 4 pylontech batteries would be £3k and then an additional £750 for an ac inverter, so £3750
At those figures it would be possible for you to get a maybe 15 year payback, but at £6.5k you are almost double that.

I'm unsure why the battery prices have jumped up right now, but I personally don't see how you can make the batteries work to give you a decent return on your investment at your lower energy usage and the higher price for the system, especially when you divert the excess solar into your car for the most part.

Yeah, I think I’m coming around to going down the solar PV only route. The solar only quote is for a 4kw array with a 3.6kw Solis inverter for £4,647. Are Solis inverters any good?

The price on the second quote has the solar install as 4.56kw with the 5kw Huawei inverter for £4,914.

QrizB

mparter said:

Yeah, I think I’m coming around to going down the solar PV only route. The solar only quote is for a 4kw array with a 3.6kw Solis inverter for £4,647. Are Solis inverters any good?

The price on the second quote has the solar install as 4.56kw with the 5kw Huawei inverter for £4,914.

Personally I'd take the 4.56kWp array but with the 3.6kW inverter, preferably for £4647

That sounds flippant but it's not meant to. The 4560W array is 12x380W , but what is the 4kW offer? 12x340? Would that installer fit 380s instead? The difference should be less than £20 a panel.

mparter

Ok, everyone seems to be telling me an inverter larger than 3.6kW is not needed. I'm assuming this is because you need DNO approval for an inverter above this? If so, why the suggestion to get more panel output? Future-proofing? Just trying to understand the thought processes.

QrizB

Panels are rated based on their performance under Standard Test Conditions, STC. That includes insolation (sunshine) at 1000 watts per squate metre directly onto the panel, plus the panel being at 25 degrees C. This is great for comparing panel performance but isn't entirely representative of the real world.

• Sunlight at ground level isn't a constant 1000W per sq. m. It might exceed that number on a particularly clear day but at other times it will be less even under a clear sky, and much less if there's any could around. On a dull day it will struggle to get to 100W. And the panels themselves get dirty.
  
• The sun moves but your panel doesn't, so there will only be two days a year where the sun shines directly onto your panels. All the rest of the time it will be at an angle which will reduce performance.
• Solar panels get hot;they're out in the sunshine, after all. On a bright summer's day they might be at 65 degrees C or hotter.

All these things mean that, most of the time, your panels will be producing less power than they are rated at, so usually you will be better served by a smaller, cheaper and more efficient inverter.

Solarchaser

Yep exactly as QrizB says.

You really want the most solar you can have on your roof.

In reality you will have far too much solar during the summer, and not enough in the winter.
A smaller inverter is more efficient in the winter months when you are most interested in the output.

Personally I'd go back to the solar only company and have a conversation around the higher wattage panels offered by the other company, there is always wiggle room for them on profit.

Solis is a pretty well known brand, and well thought of too, so I'd work on getting that quote reduced, and the panel output increased