Combining two strings, one SE facing the other SW

[openspaceman]

I'm getting three quotes for a fresh install at a house on the south coast, Shoreham, I am hoping to fit 2kW peak capacity on each hipped roof which should be good for an annual 3600kWh. There is no shading.

The plan is to fit a Zappi to charge an EV (Kona), are they easy to program to accept off peak electricity as well as divert solar power to the car?

Motivated by increase in electricity prices and spending some savings before they become worth less.

I'm not sure of the benefit of extra battery storage in this case apart from summer months when car is out and about as charging the car is likely to be the main way to absorb surplus.

[Stinsy]

Most suitably-sized inverters will have connections for two independent strings so no problems there.

I would still recommend a hybrid inverter and small-ish battery though. The car is likely to be out at least some of the time, or its battery might be full. And the sun has a habit of going behind a cloud just as the heating element on your washing machine kicks in!

In addition the house battery will reduce peak electricity usage in winter which you cannot (yet) do from your BEV.

[nowty]

If you've no shading I would think you will get more like 4200 kWh per year based on PVGIS and my own experience from your location.

You do know there is zero VAT at the moment so if you don't install even a small battery with a hybrid inverter now, I guarantee you will regret it later. It cannot be retrofitted at zero VAT later on.

[marshman]

I have to agree with Nowty. a) you will get more than 3600kWh a year and b) get a hybrid inverter and fit a battery - doesn't need to massive just enough to do some "peak shaving" - with VAT at 0% that is quite a saving and also doing it all now saves hassle and paperwork later. I never regretted an investment (and it is an investment rather than expense) in R.E. or energy saving.

[openspaceman]

Would anyone care to explain the differences between hybrid and other inverters?

[nowty]

Would anyone care to explain the differences between hybrid and other inverters?

A standard inverter just works with your Solar panels.

A hybrid inverter works with both inverter and batteries connected to it so its one unit and not much more in price.

Example, if you fit the cheapest system with a standard inverter and solar panels, then later you want batteries, you need to buy another battery inverter + paperwork with DNO. Or replace the standard inverter with a hybrid and have the hassle of selling the old inverter. And either way later on pay the 20% VAT.

[openspaceman]

I see. I quite liked the idea of your sunny island so that would need a separate inverter to work as an eps and keeping the panels generating I think.

Also once set up this would have to run basically with no intervention, so in the winter months the battery would have to be prevented from discharging into the EV if off peak tariff is found.

The Octopus tariff seems to need a battery (charged at offpeak in winter) just to carry the house through that high extra peak rate in the evening,

[nowty]

Most decent hybrid inverters should do what you want, i.e. be configured for timed standby or charging from grid if required in winter.

The point we are trying to make is that with the current zero VAT deal you really want a one off install with everything zero VAT. Anything retrofitted later will cost you full VAT and will usually cause additional paperwork or modification to existing systems.

[openspaceman]

Yes I had taken that on board so thanks to all three of you for that.

[Ken]

I think the 3600kwh/yr is not unrealistic considering the E/W

For anyone else reading that inverter/battery advice does not apply to PV system operating under FITS unless one has DNO permission.