Best inverters for beating load-shedding

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2023-02-13 at 14:45 #393297

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South Africans looking for a capable home backup power system should take great care when choosing an inverter.

While batteries and solar panels tend to be more flexible in terms of upgrades down the line, inverters can run into big compatibility problems that might require replacing them altogether when upgrading.

From a technical standpoint, batteries and solar panels are far less complex than inverters.

An inverter’s primary purpose is to convert direct current (DC) electricity, generated through sunlight or stored in batteries, into alternating current (AC), which is useable electricity.

High-quality inverters feature various control circuits, switches, and transformers to ensure they handle the process safely and efficiently and that the electricity delivered to your appliances does not damage them.

To decide which inverter to buy, you must first consider what type of backup system you want.

Most households in South Africa are opting for a combination of photovoltaic solar and battery backup to generate and store cheap electricity they can use when they experience load-shedding.

There are three types of solar power systems:

Grid-tied — Solar power and grid run in parallel, with solar being consumed first. Most affordable inverters that support this cannot feed electricity back into the grid, while some also require a live grid connection to function.
Off-grid — Designed for running without grid power but can also be connected to the grid. As long as solar or batteries have enough capacity, they will provide power. Inverter will switch over to grid if capacity becomes insufficient. Electricity cannot be fed back into the grid.
Hybrid — Can be either grid-tied or off-grid, but always uses an inverter that can use a mix of solar and grid electricity, as required.

Examples of total off-grid inverters include those that come in power trolleys.

These are the most affordable but have more limited use than hybrid off-grid or hybrid on-grid inverters.

In addition to being unable to feed power back into the grid, they can have fewer safety and voltage management features.

As a result, they are generally only considered for connecting to a handful of appliances and not through a distribution board.

Hybrid off-grid vs hybrid on-grid

Hybrid off-grid inverters can only supply solar or stored battery power when they can carry the entire load at a given time.

In cases where they cannot, all electricity supply to the house will come from the grid.

That means during peak usage periods when your home’s demand might exceed the capacity of your inverter, solar capacity, or battery, you will have to rely on the grid only.

Hybrid off-grid inverters are also incapable of feeding power back into the grid, so you won’t be able to benefit from a future feed-in tariff.

An on-grid hybrid inverter —like those from Deye, Sunsynk, and Victron — can use solar and grid power simultaneously.

This process — called blending — ensures you use all available resources.

Typically, the same types of inverters can be stacked to provide higher total output.

For example, two Sunsynk 5kW hybrid inverters can be combined to provide a 10kW output.

Six brands tend to pop up when we ask reputable solar installers about the most reliable inverter manufacturers.

These are Axpert, Deye, Growatt, LuxPower, SunSynk, and Victron.

Several brands — including Kodak, Magneto, Mecer, and RTC — rebadge Axpert inverters.

While their software, warranties, and customer support agreements might differ, they are made from the same components.

The same can be said for Deye and SunSynk, which are both made by Deye.

Axpert, Growatt and LuxPower models are off-grid hybrid inverters, while Deye, SunSynk, and Victron are on-grid hybrid inverters.

How prices stack up

We compared the prices of inverters from these six brands to see which was the cheapest per kW of capacity.

We focused on the three most common capacities for entry-level solar inverters — 3kW, 5kW, and 8kW.

From the group of hybrid off-grid inverters, we found that the rebranded Axpert inverters were the cheapest, with Mecer’s being the most affordable for 5kW and 8kW options.

When it came to hybrid on-grid systems, Deye was the cheapest option for 3kW, 5kW, and 8kW capacities.

The tables below compare the prices of reputable hybrid off-grid and hybrid on-grid inverters in South Africa.

Prices were taken from well-known online stores dealing in energy equipment, including GeeWiz and Solarway Suppliers.

Hybrid off-grid inverters
Inverter	Maximum output	Price	Price per kW
Geewiz Axpert 24V	3kW	R6,495	R2,165
Growatt 3kW 24V	3kW	R7,299	R2,433
Mecer Axpert 3kW 24V	3kW	R7,495	R2,498
RCT Axpert 3kW	3kW	R7,859	R2,620
Mecer Axpert 5kW 48V	5kW	R10,348	R2,070
Growatt 5kW 48V	5kW	R12,899	R2,580
Luxpower 5kW 48V	5kW	R14,995	R2,999
Mecer Axpert 5.6kW 48V	5kW	R14,995	R2,999
Mecer Axpert 8kW 48V	8kW	R21,125	R2,641
RCT Axpert 8kW 48V	8kW	R25,731	R3,216

Hybrid on-grid inverters
Inverter	Maximum output	Price	Price per kW
Deye 3.6kW 48V	3.6kW	R15,999	R4,444
Victron Energy 3kW 24V	3kW	R16,930	R5,643
Victron Energy 3kW 48V	3kW	R17,894	R5,964
Sunsynk 3.6kW 48V	3.6kW	R21,895	R6,081
Deye 5kW 48V	5kW	R24,899	R4,980
Victron Energy 5kW 48V	5kW	R27,193	R5,439
Sunsynk 5kW 48V	5kW	R27,995	R5,599
Deye 8kW 48V	8kW	R39,500	R4,938
Sunsynk 8kW 48V	8kW	R40,825	R5,103
Victron Energy 8kW 48V	8kW	R48,516	R6,065