Start with loads, not panels
List what must keep running and for how long: lights, Wi-Fi, TV, fridge, alarm, gate, and whether you want geyser or air conditioning included. Multiply each load's power by the hours you want it supported. That total, in kilowatt-hours, is your usable storage requirement.
The details that catch people out
- Usable versus nominal capacity — lithium batteries should not be planned to 100% depth of discharge.
- Inverter capacity — storage does not help if the inverter cannot deliver the peak load. Air conditioners and geysers have high starting demand.
- Essential loads separation — without correct DB work, the system tries to back up the entire house.
- Recharge time — a battery you cannot refill from your array by the next evening is undersized on the generation side.
Sensible approach
Size the essential-loads board first, then the inverter, then the battery, then the array to refill it. Doing this in the wrong order is why so many systems disappoint.