Are solar batteries the best for backup power?

In this post, we explore home backup power systems. We compare the two main types, namely solar batteries and generators, to work out which is the better option.

Do you need backup power?

Backup power is necessary where you have persistent power cuts. This could be because of load shedding or blackouts. I’ve written before about why we have power cuts in Zimbabwe and why they’re likely to continue here.

While most people get backup power for their homes, it’s just as useful if not more if you run a business. But which is the best backup power solution? 

Types of backup power systems

There are two options to choose from. You can either opt for a solar system with batteries or a backup generator.

A solar system with batteries

This is the more expensive option. It is, however, a more permanent solution. Solar panels last about 25 years. Inverters last 10 years and solar batteries have a lifespan of 5-10 years.

Solar can work without batteries in a grid-tie solar system. This makes the system cheaper but removes the power backup.

Adding batteries makes sure you have power in a blackout. Batteries also reduce your dependence on grid-supplied electricity by up to 90% saving you money on your electricity bill.

Backup generators

Most generators in Zimbabwe use petrol or diesel. For years generators have been the more popular option as a backup power solution because they’re cheaper and simpler to install.

How does having solar batteries compare against using a generator?

Solar batteries versus generators

Generators provide more backup power than batteries and can handle heavier loads.

They have a lower upfront cost so are cheaper in the short run. In the long run, however, the costs work out almost the same when you factor in fuel, maintenance and the shorter lifespan of a generator.

Home generators require maintenance much like a car battery. To keep it in good condition, run a generator once a week for around 30 minutes. This should be included in your maintenance costs.

Because they run on petrol or diesel, generators are less environmentally friendly than solar batteries. If you’re worried about your carbon footprint, batteries are the friendlier option.

Solar batteries have up to twice the lifespan of a generator. A generator typically lasts 5 years. Batteries can last between 5-15 years depending on the type of battery. Here’s a guide on how to compare and choose a solar battery.

GENERATORSOLAR BATTERIES
Switching on when the power goes outTakes a few minutes to switch on and power up.Backup kicks in instantly.
Energy capacityMore electricity per $ spent.Less electricity per $ spent.
Noise levelModerate to High.Low.
MaintenanceRefuelling. Oil change every thousand hours (at least once a year).Minimal.
Lifespan5 years.5-10 years.
CostCheaper up front.More expensive up-front
Recommended useCritical loads that require more energy.Smaller loads, off-grid.
Environmental impactHigh due to use of fossil fuels and exhaust fumes.Low.
Here’s a complete summary of batteries versus generators for backup power.

Conclusion: Should you get solar batteries?

A generator is the cheaper short-term solution. In the long term, solar is more cost effective. While it requires more money upfront, you’re getting a longer lifespan for every dollar spent. Generators remember, need refuelling and have a shorter lifespan.

Also, with solar batteries, you can use them even if there isn’t a power cut. This extended use helps you reduce your electricity bill and recoup the money you spent on the solar system.

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