The next step involved in sizing your system and also in determining how to calculate solar panel battery and inverter is to size your charge controller but before then we have to understand some components which you probably have not encountered and so do not understand this will give you a better understanding of the calculation.
Calculate size of solar panel battery bank and inverter excel.
The solar battery calculator applies the best practices for using the depth of discharge dod of different types of solar batteries thus ensuring the optimal compromise between the size of the battery bank and the desired long life of the batteries while taking into account their type.
Think of this as the minimum battery bank size based on your typical usage.
Once you have sized your battery bank and solar panel array determining which charge controller to use is comparatively straight forward.
If inverters were 100 efficient all of the power flowing from the battery would be inverted for use by the load and the inverter would consume no power at all.
Take the power produced by the solar panels and divide by the voltage of the batteries.
I have seen the excel sheet you have prepared for design of solar panel inverter and battery bank and it is awesome.
I want to maintain the 70 c temperature of 50 liters approx water using 500 w dc heater for 24 7.
This requires an increase in current flow from the battery to run the inverter.
You may want to consider 600 800 amp hours of capacity based on this example depending on your budget and other factors.
In reality however inverters consume some of the power that flows from the battery while inverting.