@yachtsman,

I have no knowledge of PV or home batteries so I'm no direct help.  However there is quite a lot of discussion on them in this forum, including price, size, roof orientation, etc.  If you join and post there you'll get a 'frank' view of your proposed installation. 

https://forums.moneysavingexpert.com/categories/green-ethical-moneysaving/

@derek-m I don’t have a breakdown of the individual costs just a list of components as listed with a total cost including installation, with the usual provisos of extra charges for unplanned work etc.

Im lead to believe the Tesla powerwall 2 is only one size 13.5kW

Posted by: @yachtsman

@derek-m I don’t have a breakdown of the individual costs just a list of components as listed with a total cost including installation, with the usual provisos of extra charges for unplanned work etc.

Im lead to believe the Tesla powerwall 2 is only one size 13.5kW

 

You are undoubtedly correct, I did not Google or research the Tesla system. Kev's advice is probably the best to follow, since they may be more knowledgeable on that site when it comes to costs.

@kev-m Thanks for the link Kev, I’ve now registered & waiting for acceptance.

@yachtsman, I would always recommend getting 3-4 installers to quote for projects like this because it'll automatically give you a price range and wider array of options. We received six quotes before committing. I would say, based on our array, that the price is a bit high albeit with the very expensive Tesla Powerwall. Personally, I'm not convinced about the ROI of batteries, but each homeowner will their own objectives. Batteries can definitely be very helpful, but I would ask the installer to check stock levels because I think the Tesla Powerwall batteries have pretty long lead/delivery times if you go down that route.

Another thing to look out for is the size of the inverter. Your quoted array is 4.5kW and they've quoted for a 3kW inverter which means your panels will never produce more than 3kW in the height of the summer. I know that smaller inverters are recommended for better production in the winter months, but I think it's negligible and would personally prefer a larger inverter. I'd probably get a 4kW. 

Since you already have a Tesla EV, you may want to hold out for vehicle to grid/home to become more mainstream as that would save you on the expense of the battery. 

@editor say what you like about batteries, but the ROI can be very good. Mine is 18.5% this year so far. I wouldn't be surprised if they save me maybe £600 by the end of the year. In the last 2.5 years we've had them, they've paid back 34% (£903) on cost. They've provided 35% of our total power use this year.

@editor Apologies for the late response. I take your point about the inverter size. I’m having issues getting alternative quotes. One company would not do a site visit using Google earth to view the property instead & finally saying it would not be practical to use a PV system.

Two others will only visit site after I pay a site visit fee, which will not be a full survey, that comes later after an order has been placed. 

@yachtsman honestly you don't really need a quote to build a system. There are plenty of websites where you can build out a PV system and cost it. Essentially you need a few elements;

1. panels (obviously)
2. string or micro inverters
3. hybrid inverter (for the battery)
4. batteries

What you need is a quote to fit the system - there should be a good number of installers locally who can physically fit a solar system for you. Having basically ordered all my own components I would recommend you source new panels from somewhere like ebay or gumtree; going this way you can get them at 50% of the cost price. I got mine from a gumtree seller at a very reasonable cost as they weren't needed for a solar farm. Below is a schematic of my system when it was installed. The battery has now been enlarged to 14kW

On batteries you can go for the top of the range; Tesla (£7k for 15kw), middle range Pylontech (£4k for 10kw including inverter) or build your own cheaply (£1k for 10kW). Finally you can go semi DIY and use someone like Seplos. Honestly batteries are batteries, but the main difference is that Tesla will be Lithium Ion and the others are Lithium Iron Phosphate (LiFePo4). 

@batalto, batteries and ROI are how the users utilises them to their advantage – you're clearly doing very well with them and that's amazing. I just don't think we'd get the same return on our system, especially since we don't have a smart metre.

@editor we only got a smart meter in October and we had a normal tariff. The benefits for us were just running costs through the night in the shoulder seasons. This would be even greater with the ASHP as we'd make more use of power we generate. When we didn't have an ASHP we were using approximately 30% of all our power from the batteries. Most normal households the peak power demand is usually in the evening (when the sun isn't up). Below is last years figures for power use on a 7kw battery system. No smart meter and no ASHP - average of 4kw per day from the batteries. However we are now a totally electric house - all cooking is induction. We have zero gas use and we have AC which we run the summer for free (with solar and batteries). 

Expanding the batteries and moving to a smart tariff has made a chunky difference to our use of them

@batalto thanks for the tips, however I know nothing about PV systems & wouldn’t consider building or buying my own components.

Im looking for a turnkey system supplied & installed by a professional organisation. I understand I’ll pay a much higher price, but I’ll be able to sleep at night.

Hi Yachtsman,

One thing that struck me was your limited roof space for panels. 

The NE facing ones will really be quite unproductive. If you want to still use your SE and SW roof spaces I would spend the money on the best panels you can afford due to the limited number of them. 400W+ panels are now available. 

You say you are in a semi rural location. Do you have space for a ground mounted array? Or do you have or could you consider a shed/garage/summer house that's southish facing to give you more roof space to mount them? 

Just a thought.

Adam