Altering existing solar pv installation

Ballylad

Hi, some suggestions from the informed few here, I have a 5kw solar pv with 4kw inverter since 2016, Zappi for my two evs (Tesla and kona), I have ground source heat pump , granny flat off house. Night rate runs heat pump mostly in winter, evs charged off Zappi excess or night rate.Original solar pv was eligible for home renovation incentive scheme ( vat claimed back).
Was thinking of adding 3kw ground mounted with a 6kw inverter with so as to limit export to max 6kw as per esb guidelines
Pv panels approx 14 in 2 rows of 7
Original is 3 rows of 6 on roof
Am I eligible for solar pv grant for new section?
Can I add all these strings on one inverter or can you stack the 4kw inverter and a new 3kw inverter
Is 8kw pv allowed if you limit export to 6kw?
Thanks

unkel

Ballylad wrote: »

Am I eligible for solar pv grant for new section?

Yes provided your house was built before 2011

Ballylad wrote: »

Can I add all these strings on one inverter

Yes

Ballylad wrote: »

Is 8kw pv allowed if you limit export to 6kw?

Yes, if your only inverter is 6kW max, then it doesn't matter how many PV panels you connect to it. You will have to replace your existing inverter though

Coltrane

Ballylad wrote: »

Was thinking of adding 3kw ground mounted with a 6kw inverter with so as to limit export to max 6kw as per esb guidelines

That’s permitted by the ESB. Also permissible as I understand it is a larger-capacity (e.g. 10kW) inverter which can programmatically limit export to 6kW (presumably more expensive but more flexible in case the 6kW is increased).

Ballylad

Coltrane wrote: »

That’s permitted by the ESB. Also permissible as I understand it is a larger-capacity (e.g. 10kW) inverter which can programmatically limit export to 6kW (presumably more expensive but more flexible in case the 6kW is increased).

Was talking to a boards recommended installer today, he said 5kw is max inverter you can use on single phase, is this true?

unkel

No

graememk

I think you can have more than one inverter too, as long as your max export is limited to 6kw. (Oh and to claim grant you will need to have a C Rate Ber or above after the work is done)

Do investigate non grant installs too, might work out cheaper, esp if your going solar only.

unkel

If you can fabricate the frame yourself, you could do a ground mount system for very cheap DIY. Just replace the existing inverter with a beefier one (also DIY) and get your parts cheaply

4kW inverter + 2kW inverter = 6kW limit

Ballylad

Sir Liamalot wrote: »

4kW inverter + 2kW inverter = 6kW limit

Think for me anyway it’s not worth applying for grant, prices seem inflated, is there any other way to limit your output to grid to 6kw , is there any device that controls the limit?, how do you set up two inverters , have they to be the same model, electrical circuits is not my thing!

unkel

Ballylad wrote: »

is there any other way to limit your output to grid to 6kw , is there any device that controls the limit?

There are inverters that can limit their export to the grid, but I don't think the ESB allows that. I.e. I have an AC side battery inverter that can output 3kW. I also have a solar inverter that can output 3.6kW. The ESB adds these up so technically I am over the limit. Although it is impossible for me to export more than 3.6kW to the grid (and only if I use zero electricity in the house) as the battery does not discharge if the house does not draw. Never mind it exporting. The ESB rules are a load of bollox.

Ballylad wrote: »

how do you set up two inverters , have they to be the same model

They can be setup completely independently of each other. Each has their own RCBO / breaker in your consumer unit, each has their own circuit. Each has their own string or strings of solar panels attached to it. They can be completely different make / model / rating.

GTIs are synchronising...any will do.
That's the easiest way. Add another as soon as you get the paperwork if you want to exceed it.