I have two sunsynk 5kw inverters connected in parallel but they produce very little power (peak about 2.5 kw)..

Ive got 28 400w solar panels facing either due South or due East / West (i'm UK based).

I also have 6 sun synk 5KW SSLBL batteries connected in an unusual manner (3 batteries on 1 inverter and 3 more on the other inverter). I've asked the installer for an install like that on the sunsynk wiring diagram (diagram 4 from https://www.sunsynk.org/post/line-drawings )

I cant remember the exact panel to string configuration but from memory they are fairly well balanced. However, from the app Looking at the input voltages over the two inverters I see very little input voltage on the second string (such that I dont think we satisfy the startup voltage):

As you can see they are much lower than the input voltage on the first string and they never ramp up throughout the day.

The system is not in timer mode yet (until the install is complete) and the batteries are fully charged so it could be that theres just not enough demand for it. Is the second string low because of a lack of demand or would I expect to see a higher voltage even at this stage?

I strongly suspect its not a demand driven issue tbh as when we have high loads the system still pulls a lot of energy from the grid.

Thanks in advance for any thoughts.