Choosing the wrong inverter is the most expensive mistake in a home solar system. Too small and it trips every time the kettle and microwave run together. Too big and you paid for capacity you never use. Here is how to size one properly for a South African home.

Step 1: Decide what must run during an outage

An inverter does not need to power everything in the house. Most people back up the essentials: lights, fridge and freezer, TV and Wi-Fi, laptops and phone chargers, the gate motor and alarm, and often the kettle and microwave. Big heating loads such as the electric geyser, stove, oven and tumble dryer are usually left on Eskom or a separate circuit, because they would need a far larger system.

Step 2: Add up what runs at the same time

The inverter size is set by your peak load, the total wattage of everything switched on at once. Typical figures:

• LED light: 5–10W each
• Fridge/freezer: 100–200W running
• TV and decoder: 100–200W
• Wi-Fi router and laptop: 50–100W
• Microwave: 1,000–1,500W
• Kettle: 2,000–2,200W
• Borehole or pool pump: 750–1,500W

A household running lights, fridge, TV, Wi-Fi and a kettle at the same moment is already at about 2.7kW.

Step 3: Allow for surge and headroom

Motors in fridges, pumps and gate motors draw two to three times their running power for a second when they start. Add 25–30% headroom on top of your peak load so the inverter is not running at its limit and has room for surges.

Which size fits which home?

• 5–6kW: the right size for most homes that back up essentials plus the kettle and microwave. Our 5.5kW and 6.2kW inverters fall here, and the 6.2kW dual-output models let you split essential and non-essential loads.
• 8–10kW: larger homes, or homes that want to run a pump, air-con or more appliances together. See the 10.2kW stand-alone inverter and the Deye 8kW hybrid.
• 12kW and up, or three-phase: farms, workshops and small businesses. Talk to us about the Sunsynk 16kW or Deye 15kW three-phase models.

Match the battery voltage

All our inverters in this range are 48V. They pair with any of our 51.2V lithium batteries, and you can add more batteries later as your budget allows.

Still not sure?

Try our solar system sizing calculator, or look at our complete solar kits, which pair an inverter, battery and panels that are already matched. You are also welcome to contact us with a list of what you want to run, and we will recommend a size.

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