Good morning,
@ Jo, no, it isn’t the way you think, check this topic first, VDC ripple improvements
@ Stefan and Thomas, for that we need first all above mentioned information.
Better is, to make a graph in VRM to see the voltage drop, amperes and ripple when you start your heavy load, then things can be calculated accordingly with the real data instead trying to calculate this theoretically in advance.
Normally we test first bog standard and improve the system only when needed as it is an add-on and easy to install.
3 fast shortcuts can be made in general;
1 for the ripple improvement, first place the same amount (or slightly more, +20%) of F in electrolytic capacitors (which are already in the inverter) over the inverter to battery terminals individually, this should reduce the ripple with at least 35-45%, place several smaller ones to handle the total ripple current instead of 1 big capacitor.
2 for the start load improvement, place a minimum of 2/3 of the battery capacity in KWh in F in supercapacitors (more is pending on voltage drop, etc) over the terminals of the battery, 30KWh is about 20F, be sure there is only a small ripple, as these do not handle ripple very well.
3 for further ripple and load improvements (if needed, very very rare), a CLC circuit must be made in the busbar line, see above mentioned topic for that, pending many variables.
But there it can be 1/20 KWh/F with electrolytic capacitors and the L must be chosen to handle the maximum current of the inverters and in between 0.68-3.3micro-H and between 0.13-0.42milli-Ohm.
Various L-s or complete CLC-s can be placed on the busbar in parallel to handle the total current.
This is a bit costly but we place those only in case of long cables from the inverters to the batteries, so at home that’s not the case normally and not needed.
Regards, Jeroen.