Connecting two Growatt hybrid inverters in a UK single phased home

[duckville]

Hi all,

Just looking for some feedback on a planned system. I already have a 8.2kw E/W solar array with a 6kw Growatt SPH6000 installed along side x3 6.5kwh Growatt batteries totalling 19.5kwh. Systems works great and I monitor it via Solar Assistant.

The plan is to add another 3.4kw of panels on a vertical south facing wall. G99 all sorted, just not sure about the inverter.... My installer said I could have a simple string inverter added to the system and my hybrid will most likely charge the batteries from the two strings it has already and from have the newly installed 3rd string. The SPH6000 can discharge at a rate of 4kw from the batteries. Another option is to have another hybrid e.g. a 3kw Growatt and connect both inverters via Growatt's SEM (Smart Energy Monitoring), that would manage the 6kw limit set by DNO and it will also up my in-house discharge rate to 7kw (if I move a battery from the SPH6000 unto the SPH3000).

Has anyone used the Growatt SEM before? Thoughts on adding another hybrid inverter?

Would a simple string inverter be better?
If it where you, what would you do?

The aim is to have the highest in house discharge possible as we have most things electric e.g. car, shower, cooker. We also plan to export lots in the summer using Octopus Flux tariff.

Thanks in advance for the feedback

 

[MisterB1959]

have you considered just replacing the current inverter with a larger, albeit different make of inverter?

10kw Sunsynk Inverter (single phase) might suit your needs re high discharge and ability to handle a lot of PV? perhaps you might be able to sell your existing inverter to help subsidise the cost?

 

[duckville]

I've not considered changing the inverter. The batteries themselves have a discharge max of 4kw per hr, using my current inverter. Figured splitting the batteries and adding the 2nd inverter would up my house discharge rate to at least 7kw per hr.

 

[krombacher]

I have 2x (SPH6000 + 6.5 kw panels) + growatt batteries GBLI6532 and ARK LV.
"The SPH6000 can discharge at a rate of 4kw from the batteries" - local growatt team says it's 3 kw.
Also my 2 systems won't work together - they spook each other and as one starts to push power down the line the other one freaks out and limits PV and sometimes goes Standby mode. I can see it on the graphs in the solar assistant and they say this kind of scaling won't work - despite it's literally pictured on their frontpage, attached.

What they recommended was to setup 2 different voltage stabilizers (I have unstable grid voltage) and use each system on separate circuit.

So if you haven't installed your second system yet you better check with them for the best way in your case - before doing it.
My plan was exactly to double the output but that didn't work.