Guide

How to size a solar system in SA

Start from your bill and what must stay on in load shedding — then size panels, inverter and battery to match, with room to expand.

  1. Read the bill — monthly kWh and tariff type (inclining block, TOU, prepaid).
  2. Separate goals — bill cut vs backup hours vs both.
  3. List essentials — lights, Wi-Fi, fridge, selected plugs; leave geyser/stove off the backup board unless sized for it.
  4. Inverter kW — must cover simultaneous backup loads and solar input.
  5. Battery usable kWh — essentials watts × hours ÷ 1000, plus margin for DoD and ageing.
  6. Array size — enough to cover daytime use and recharge batteries between shedding slots.

Try the battery runtime explainer for essentials-circuit hours, then request quotes with your brief.