Two inverters working together?

DIY
1

Hi,
Brief history, I had solar and battery system installed 5 years ago. Growatt SPH6000, 7kW array and 6kWh battery. I rapidly became dis satisfied with the Growatt’s performance (it could only support 3000w when on battery etc etc). I built my own ‘powerwall’ using 16 x 280a/h EVE LifeP04 cells, a Seplos BMS feeding into a Victron Multiplus II GX inverter. The system has performed really well but I now need to expand my system due to imminent fitting of a heatpump etc.

It is my intention to remove the Growatt SPH6000 inverter and battery, add to my Victron system another inverter circa 10kW and 32 kWh of battery storage, probably from Fogstar. My questions are if anyone could advise please:-

  1. Can I common all of the LifeP04 batteries onto a DC busbar for want of a better word.
  2. Each inverter, the existing Multiplus II GX and the new 10 kW one connect on to the busbar
  3. The inverters connected together to talk to each other regarding load sharing.
  4. Do i have to put a CT on each inverter or can they share the information via comms
  5. Is there a suitable Victron MPPT charger to suit my 2 strings of panels to the batteries mentioned, the two strings are a 10 panel and a 6 panel split
  6. Which Victron inverter would you advise for the above, I’m happy to go higher than 10 kW if it’s sensible at this stage
  7. I think I’d like to wire the system so that the inverters feed my consumer units, the grid feeds the inverters so in the event of a power cut the system keeps running.

I run my existing systems via Home Assistant and I’m quite happy to that with the above or delve into code red and make it stand alone as such

Many thanks in advance.

J

2

There are strict requirements when paralleling systems. Please read the guides carefully, especially around compatibility, and do the free video training.
You cannot mix different inverters.

3

Thank you, let the bedtime reading begin.

JJ

4

Always the best place to start.
Also start here:

(just create a free account)

5

Short story from the long, no not synchronised. But maybe if you split your consumer board up and had one inverter run one side and one run the other it could work.

6

Having read the article that Nick referenced, I’m now thinking of changing both inverters, the Growatt and Victron and getting a 15kW Victron Multiplus single unit. Sort out my batteries all in parallel so effectively 3 x 16s1p LifeP04 cells. A separate charging unit for solar panels to charge the batteries and go from there unless someone suggests a better way?