Hi, I have 2 x 5kW inverters connected in parallel and 2 banks of batteries (4 x 200Ah  connected in series in each bank) connected in parallel. The battery capacity reduces to 70% from 95% on initial loading and thereafter slowly discharge at an acceptable rate. The connected load is about 750kW.

I tested the batteries with the battery analyser and they showed 100% State oh Health and 95% State of Charge before connecting the load.

What could be the problem

8 hours ago, Thembani said:

The connected load is about 750kW.

That will drain the battery quick smart. I assume you meant 750W, or 0.75kW.

The SOC indicator on Axperts is very crude, depending only on the battery voltage. It counts each 0.1V of battery voltage as 1% of capacity, which is not realistic. So treat it as very approximate. Use a Victron BMV or similar for much more accurate SOC measurement.