Energy7.06.2022

Goodbye load-shedding — generator vs battery backup price comparison

A MyBroadband analysis reveals that generators are cheaper than battery backup systems, but buyers should consider the fuel costs associated with running them.

MyBroadband compared the price of buying a generator to the cost of installing a backup battery system designed to last through bouts of up to Stage 4 load-shedding with a load of 800W.

Stage 4 load-shedding is implemented in two-and-a-half-hour segments.

Based on the requirements, a 12V battery system consisting of a 220Ah capacity would be sufficient to run an 800W load for over three hours.

Generators are generally cheaper initially, and installation is relatively inexpensive. On the other hand, battery backup systems are more expensive up-front as equipment and installation costs are high.

However, it is important to consider the fuel costs associated with running a generator, which can be high with the current petrol price in South Africa.

Generators can also create a disturbance as they produce a lot of noise.

Generator options

The generators considered had to feature an automatic voltage regulator (AVR) and be able to support a constant load of 800W.

Few sub-1,000W generators feature an AVR, which is essential as it helps maintain constant voltage supplied to electrical equipment.

As a result, we also considered generators with support for loads 1,000W and slightly above. The maximum power we included for a generator was 2,000W, assuming it fell into a similar price range.

The most cost-effective generator listed is the Mac Afric 2.8 kVA Standby Petrol Generator with an electric start at R4,895. With a rated power output of 2,000W, it is also one of the largest generators listed.

Adendorff Machinery Mart told MyBroadband that those looking for backup power solutions to power their household devices and appliances should consider an inverter generator.

They offer the best protection for sensitive electronic equipment and are quieter than traditional generators.

Five of the cheapest options that feature an AVR are listed below. We also included inverter generator options as alternatives.

Ryobi 4-Stroke Air-Cooled Generator (1,200W) — R3,999

Mac Afric 2.8 kVA Standby Petrol Generator (2,000W) — R4,495

Mac Afric 2.8kVA Standby Petrol Generator with electric start (2,000W) — R4,895

Ryobi RG-1280I Open Frame Inverter Generator (1,200W) — R4,999

Mac Afric Inverter Generator (1,800W) — R7,250

Battery backup systems

Comparatively, battery backup systems require a larger up-front investment but have don’t any additional running costs.

Lithium-ion or gel batteries are recommended over lead-acid batteries as the latter can only discharge to about 50% of its rated capacity. Alternatively, if lead-acid batteries are the only option, you will have to double the capacity.

The cheapest option costs R11,913, and the most-expensive solution listed — the EcoFlow Delta portable power station — costs R33,999. It is the only portable solution included.

A range of battery backup systems is listed below.