Adding extra Solar Panels

Oscarmax

March 2022 we installed a 4.4 kWh solar array our system is registered with Western Power G98, our system is south south west, we are considering and additional 3 kWh solar array to our north north west elevation, our roof has a 30 degree slope, we are assuming the north north elevation to be at least 30% less efficient, we are not overshadowed, we live in a  6 year old detached bungalow, the roof is easily accessed. We already have a Solax Triple AC 5.8 battery.

I am assuming I will need to contact Western Power for some advice, fortunately they are very easy to talk too.

Is this installation feasible or am I wasting my time.

ABrass

If you ran it all into the same inverter, and the inverter didn't melt, then no more paperwork is needed.

If you want to either replace the inverter with a larger one, or add a second ,your installer will need to do a G99 application of some form.

They will need to eiher request permission to export more power or installing a gizmo to prevent your system ever exporting more than 3.68kW. Normally they'd request the higher export limit and if the DNO said no or gave a different upper limit they'd install a limiter.

Oscarmax

ABrass said:

If you ran it all into the same inverter, and the inverter didn't melt, then no more paperwork is needed.

If you want to either replace the inverter with a larger one, or add a second ,your installer will need to do a G99 application of some form.

They will need to eiher request permission to export more power or installing a gizmo to prevent your system ever exporting more than 3.68kW. Normally they'd request the higher export limit and if the DNO said no or gave a different upper limit they'd install a limiter.

It would definitely  through a second invertor, I have emailed Western Power and asked from some advice.

ispookie666

Just had a shocker!
The cost for additional panels would be £3/kWp, pretty much double what I had paid and at a stretch I would be able to add 6 panels. This would still have not hit the DNO max export limit of 8.8KVA 

Oscarmax

Wow we on paid £4900 last year for our 4.4kWh system.

We have a Solis dual MPPT invertor with a 6kWh max input so in theory we could safely add 1.6 kWh panels.

[Deleted User]

Oscarmax said:

March 2022 we installed a 4.4 kWh solar array our system is registered with Western Power G98, our system is south south west, we are considering and additional 3 kWh solar array to our north north west elevation, our roof has a 30 degree slope, we are assuming the north north elevation to be at least 30% less efficient, we are not overshadowed, we live in a  6 year old detached bungalow, the roof is easily accessed. We already have a Solax Triple AC 5.8 battery.

I am assuming I will need to contact Western Power for some advice, fortunately they are very easy to talk too.

Is this installation feasible or am I wasting my time.

What is your present site export limit if you have one? For example, I have a solar inverter limited to 5kW output and a Powerwall2 also with a 5kW output limit. My site export limit is 11kVA.

I am also considering adding further solar panels to my west-facing roof with a second 5kW limited inverter. It will require a further application to my DNO ( costing £411). They may just approve the new array and keep the present site export limit, or they could increase it. In my planning, I need to consider that my site export limit will remain the same. Fortunately, the Gateway attached to a Powerwall2 is a site export limiter.

Oscarmax

Oscarmax said:

Wow we on paid £4900 last year for our 4.4kWh system.

We have a Solis dual MPPT invertor with a 6kWh max input so in theory we could safely add 1.6 kWh panels.

Our Solis invertor is 4kWh not 6kWh as stated plus a single14 amp string, due to cost versus benefits we have decided not to add any extra panels.

ispookie666

@Oscarmax curious to know how much in £/w your quote came up to. 
I could have added in total 6-7 panels split across the garage roof (E and W facing), this would result in higher peak generation. If I go with E facing, I would have helped with Feb-March generation but it would take 50 years to actually get anywhere