Load shedding
How much battery do I need for Stage 6 load shedding in South Africa?
For typical SA home essentials (lights, Wi-Fi, fridge, selected plugs — roughly 0.5–1.5 kW), plan about 5–15 kWh of usable battery for Stage 6, depending on how many hours you must cover and whether solar can recharge between slots. Size usable kWh = essential load (kW) × hours offline ÷ inverter efficiency, then add ~25% margin.
Quick Stage reference (usable kWh)
| Essential load | Stage 2 (~2 h) | Stage 4 (~4 h) | Stage 6 (~6 h) |
|---|---|---|---|
| 500 W | ~1.2 kWh | ~2.4 kWh | ~3.5 kWh |
| 1 000 W | ~2.4 kWh | ~4.7 kWh | ~7.1 kWh |
| 1 500 W | ~3.5 kWh | ~7.1 kWh | ~10.6 kWh |
| 2 000 W | ~4.7 kWh | ~9.4 kWh | ~14.1 kWh |
Figures assume ~85% round-trip efficiency. Convert usable → nameplate using your pack’s DoD (e.g. 10 kWh usable at 90% DoD ≈ 11.1 kWh nameplate).
What most SA homes actually buy
Many family homes land on a 10 kWh-class pack for Stage 4–6 essentials. Comfort loads (microwave, kettle, selected AC) push you toward 15–20 kWh. Geysers and stoves usually stay off the backup board unless the system is much larger.
Use our battery runtime tool with your watts and usable kWh, then compare installer designs — not a single online number.
Design tips that change the maths
- List essentials first, then comfort — do not size for the whole DB.
- Daytime solar recharge between slots multiplies resilience on multi-day Stage 6.
- Grid-charge schedules can top up before a known slot (watch TOU tariffs).
- Compare usable kWh on quotes, not nameplate alone — see DoD explained.