Home Energy Storage Sizing Guide for Africa: How Much Battery Capacity Do You Need?

Step 1: Calculate Your Daily Energy Consumption

The first step in sizing a home energy storage system is to calculate your daily energy consumption in kilowatt-hours (kWh). List every electrical appliance in your home, its rated wattage, and the average hours of daily use. For a typical middle-income South African home, daily consumption ranges from 15–30 kWh, with the largest loads being geysers (water heaters), air conditioners, and electric stoves.

Appliance	Wattage	Daily Hours	Daily kWh
LED Lighting (10 bulbs)	100W	6h	0.6 kWh
Refrigerator	150W	24h	1.2 kWh
TV + Set-top Box	120W	5h	0.6 kWh
Laptop × 2	90W	8h	0.7 kWh
Phone Charging × 4	40W	4h	0.2 kWh
Fan × 2	100W	8h	0.8 kWh
Essential Load Total			4.1 kWh/day

Step 2: Determine Required Backup Hours

In South Africa, load shedding schedules typically last 2–4 hours per event, with up to 3 events per day during Stage 6. For full Stage 6 protection (12 hours of daily outages), you need enough battery capacity to power your essential loads for 12 hours. For the example above: 4.1 kWh × (12/24) = 2.05 kWh minimum usable capacity.

For the Solarens M16S LiFePO4 battery with 80% depth of discharge, a 5 kWh battery provides 4 kWh usable capacity — sufficient for 24 hours of essential load backup or 12 hours of moderate load backup.

Step 3: Match Inverter Size to Peak Load

The inverter must handle your peak simultaneous load. If you run a refrigerator (150W), TV (120W), 5 LED lights (50W), laptop (45W), and a fan (50W) simultaneously, your peak load is 415W. The Solarens SI3KS (3kW) hybrid inverter provides 3× headroom — essential for motor start-up surges from refrigerators and fans.

Household Size	Essential Load	Recommended Battery	Recommended Inverter
Small (1–2 people)	1–2 kW peak	5 kWh (M16S × 1)	SI3KS (3kW)
Medium (3–4 people)	2–4 kW peak	10 kWh (M16S × 2)	SI5KS (5kW)
Large (5+ people)	4–6 kW peak	15 kWh (M16S × 3)	SI6KS (6kW)