Adding extra solar (third string) to existing setup

Good morning

Original install - 2 strings on my roof (7 South facing / 4 west facing) total 3.6kw ( 11 x 320w panels) with a Solis 3.6kw Inverter.

Subsequent install of an 8.2kw GE battery with AC3 and then a second of 9.5kw GE battery with another AC3.

I want to add more solar via a pergola in the garden (probably 8 panels at 420w) but how I add this to my system in terms of inverters / hybrid inverters, can this added, so that current set up sees the extra solar and can fill the batteries? Can I get a solar inverter that allows 3 strings?

I manage batteries / EV charging (octopus) via HA set up.

I ask on here as I know that many solar installers will give me a reply that’s suits their business and not necessarily my best option(s)

TrignFlo I'm not an expert, but there are solar inverters out there that support 3 strings - of course you will need to ensure each strings voltage/current etc fits within the range.

Just as an example Growatt MIN 8000 TL-X2 Three MPPT 1ph has 3 inputs (& MPPT) - that looks to be a string inverter.

Just found Fox ESS KH 8kW 1ph Hybrid Inverter which is hybrid and 3 string or Fox ESS KH 10kW 1ph Hybrid Inverter which has 4 string. None of these are recommendations, just to show that it looks like you can get string or hybrid inverters with more than 2 string on a single phase

Thanks for the reply. Will have a look probably the easiest route to swap out inverter.

Does it actually need to know about the battery? If you have an independent inverter it will either just power the house load or export. The main inverter will spot the reduced house load so divert more charge to battery.

Obviously a separate inverter can't charge the DC battery directly, but the result should be very similar.

In a way you are correct but I’m going to need to get an inverter one way or the other, so if I could get a single inverter for all three strings then control via HA would remain as it is currently.

I think both are options moving forward.

TrignFlo

You don't really 'control' the solar inverters in HA, you just monitor them. You'll be controlling the AC-3s, and that doesn't change.

With 20:20 hindsight a single Tesla Powerwall 3 could handle all three strings and provide about 80% of your battery capacity...

That might take a bit more convincing for the boss of the house, but I like your thinking!

Solis do inverters that support three strings.
I’d suggest that as a cheap option.

If money was not an object and you draw over 3kW, I would look at a battery setup that can deliver more power than an AC3. That however will likely never pay for itself.

An unfortunate drawback of being an early adopter of solar is there are many better setups available now. I’ll also look at Solis. Thanks for the reply.