Question 1

What size inverter do I need for my home?

Accepted Answer

It depends on what you want to run. For basics (lights, TV, Wi-Fi, phone charging), a 1-2 kVA inverter is enough. If you want to run a fridge, microwave, and a few lights, you need 3-5 kVA. For the whole house including a geyser or stove, you need 8-10 kVA or more.

Question 2

How many batteries do I need?

Accepted Answer

This depends on how long you want backup power and how much you're running. For example, to run a 500W load for 4 hours, you need 2,000Wh of battery capacity. With a 5.12 kWh lithium battery, that gives you about 8-10 hours of light use. Most homes need 1-3 batteries.

Question 3

What is the difference between kVA and kW?

Accepted Answer

kVA (kilovolt-amps) is the total power capacity of the inverter. kW (kilowatts) is the actual usable power. For most inverters, multiply kVA by 0.8 to get kW. So a 5 kVA inverter gives you about 4 kW of usable power.

Question 4

Can I add solar panels to my inverter later?

Accepted Answer

Yes, if you buy a hybrid inverter (not just a standard UPS inverter). A hybrid inverter can charge batteries from solar panels AND from the grid. This is the recommended option even if you don't install solar immediately — it keeps the option open.

Question 5

How much does a full backup system cost in South Africa?

Accepted Answer

A basic system (3 kVA inverter + 1 lithium battery) costs R25,000-R40,000 installed. A mid-range system (5 kVA + 2 batteries + solar panels) costs R80,000-R150,000. A full off-grid system costs R200,000+. Prices vary by brand and installer.

Question 6

Will my inverter run my geyser?

Accepted Answer

A standard electric geyser uses 2-3 kW. You'd need at least a 5 kVA inverter and it would drain your batteries very fast. Most people exclude the geyser from backup power or switch to a solar geyser or gas geyser instead. It's not worth running on battery.

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