Battery Backup vs Alternator: Which Backup Power Source Is Best For You?

Battery Backup vs Alternator: Which Backup Power Source Is Best For You?

When you live somewhere with severe weather or regular power outages, it’s a good idea to have a backup power source for your home. There are different types of backup power systems on the market, but they all serve the same primary purpose: keeping your lights and appliances on when the power goes out.

May be a good year to consider standby power: Much of North America in High risk of power outages this summer Thanks to an ongoing drought and forecast above-average temperatures, the North American Electricity Reliability Authority said Wednesday. Parts of the United States, from Michigan to the Gulf Coast, are at high risk which increases the potential for blackouts.

In the past, Fuel Backup Generators (also known as all-home generators) have dominated the standby power supply market, but reports of the dangers of carbon monoxide poisoning have led many to seek alternatives. Battery backups have emerged as a more environmentally friendly and possibly safer option for conventional generators.

Despite performing the same function, battery backups and alternators are different devices. Each one has its own set of advantages and disadvantages, which we will cover in the following comparison guide. Keep reading to learn the key differences between battery backups and alternators and decide which option is right for you.

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Home battery backup systems, such as the Tesla Powerwall or LG Chem RESU, store energy, which you can use to power your home during a power outage. Battery backups run on electricity, either from your home’s solar system or from the electrical grid. As a result, they are better for the environment than fuel-powered generators. It’s also better for your wallet.

Separately, if you have a time-of-use utility plan, you can use a battery backup system to save money on your energy bills. Instead of paying high electricity prices during peak hours of use, you can use the power from your backup battery to power your home. In off-peak hours, you can use electricity as normal – but at a cheaper rate.

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On the other hand, standby generators connect to the electrical panel in your home and start automatically when the power goes out. Generators run on fuel to keep the electricity running during an outage – usually natural gas, liquid propane, or diesel. Other generators have a “dual-fuel” feature, which means they can run on natural gas or liquid propane.

Some natural gas and propane generators can be connected to your home’s gas line or propane tank, so there is no need to manually refill them. However, diesel generators will need to be increased in order to continue to operate.

Backup Battery vs Alternator: How Do They Compare?


In terms of cost, battery backup is the most affordable option up front. But generators need fuel to run, which means you’ll spend more over time to maintain a steady fuel supply.

With battery backups, you’ll need to pay for your battery backup system up front, plus installation costs (each in the thousands). The exact price varies based on the battery model you choose and the number of appliances you need to power your home. However, it is common for a mid-size home battery backup system to run between $10,000 and $20,000.

For generators, the initial costs are slightly lower. On average, the purchase and installation price of a backup generator can range from $7,000 to $15,000. However, remember that generators require fuel to run, which will increase your operating expenses. Specific costs depend on a few factors, including the size of your generator, the type of fuel it uses, and the amount of fuel used to power it.


Battery backups gain a slight advantage in this category as they can be wall or floor mounted, while generator installations require a little extra work. Regardless, you’ll need to hire a professional for any type of installation, both of which require a full day’s work and can cost several thousand dollars.

Aside from setting up the equipment itself, installing the generator also requires pouring a concrete slab, connecting the generator to a dedicated fuel source and installing a transfer switch.

Maintenance work

Battery backups are the clear winner in this category. It is quiet, operates autonomously, produces no emissions and requires no ongoing maintenance.

On the other hand, generators can be noisy and annoying when they are in use. They also emit exhaust or fumes, depending on the type of fuel you use to run – which could annoy you or your neighbors.

Keeping your home energy

As much as they can conserve power in your home, backup generators easily outperform battery backups. As long as you have enough fuel, generators can run continuously for up to three weeks at a time (if needed).

This is simply not the case with battery backups. Let’s use Tesla Powerwall as an example. she has 13.5 kWh of storage capacity, which can provide power for a few hours on its own. You can get extra power from it if it’s part of a solar panel system or if you use multiple batteries in one system.

Life expectancy and warranty

In most cases, battery backups come with longer warranties than backup generators. However, these guarantees are measured in different ways.

Over time, battery backup systems lose the ability to hold a charge, just like phones and laptops do. For this reason, battery backups include an end-of-warranty capacity rating, which measures how effectively a battery can hold a charge by the end of its warranty period. In the case of Tesla, the company guarantees that the Powerwall battery should retain 70% of its capacity by the end of the 10-year warranty period.

Some spare battery manufacturers also offer a “productivity” guarantee. This is the number of cycles, hours, or output power (known as “productivity”) a company guarantees on its battery.

With standby generators, it is easy to estimate the life span. High quality generators can run for 3000 hours, provided they are well maintained. So, if you run your generator for 150 hours a year, it should last about 20 years.

Which one is right for you?

Across most categories, battery backup systems come out on top. In short, it is better for the environment, easier to install and cheaper to run in the long run. In addition, they have longer warranties than standby generators.

nevertheless, Conventional generators can be a good choice in some cases. Unlike battery backups, you only need one generator to restore power in the event of a power outage, reducing initial costs. In addition, backup generators can last longer than battery backup systems in a single session. As a result, it would be a safer bet if the power went out for several days at a time.

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