Home backup batteries can provide a reliable source of electricity for your household during power outages or in off-grid locations.
The home backup batteries in portable power stations can also reduce your dependence on the utility grid when you add solar panels to capture clean, renewable energy from the sun.
But how long can a home backup battery last when a blackout comes? Will it be enough to see your home through an extended power outage?
And what about over the long term? Is it worth the investment?
In this article, we’ll explore the factors determining how much home backup battery capacity you need to keep your household safe during a power outage.
You’ll also learn what influences the life expectancy and performance of a home battery backup system — and about the benefits of a battery that offers solar charging to keep the lights on longer when the grid goes down.
How Long Can a Backup Battery Power a House?
How long a home backup battery can operate without recharging depends on numerous factors. The most crucial are:
- Battery storage capacity (when fully charged)
- How much electricity you consume
- Available charging options
If you’re using a portable power station paired with solar panels, your home backup battery can recharge while it’s running any time during daylight hours.
If you rely solely on AC electricity from the grid to keep your home backup up battery charged, it may run out of juice long before a blackout ends.
If you’re using a portable power station for home backup, its output capacity determines how much electricity can produce at any given time.
For example, a 10 kWh home backup solution can produce up to 10,000Wh of continuous power. Considering The average UK household consumes around 8.5 kWh of electricity daily or 255 kWh a month, you’d need to look at a high-capacity home backup battery — like EcoFlow’s DELTA Pro — to back up an entire home.
Solar Charging for Home Backup Batteries
If you use a home backup battery with the option to charge using solar panels — such as an EcoFlow portable power station (PPS) — the output capacity determines the maximum amount of electricity your solar power system can provide at one time.
The battery storage capacity determines how much electricity your solar system can hold before fully charging.
The more electricity your solar panels generate, the larger the solar battery in the PPS needs to be to store it. Once your home backup battery is fully charged, any additional solar energy captured will be lost.
To put it simply, the more solar panels you deploy — and the higher the rated power of the solar panels — the bigger your home backup battery needs to be to ensure that valuable electricity doesn’t go to waste.
The output capacity of residential solar power systems is typically measured in watt hours (Wh) or kilowatt hours (kWh). One kilowatt-hour (1 kWh) is the amount of electricity expended to keep a 1000-watt (1000W) appliance running for an hour.
For reference, the average home refrigerator consumes between 300 – 600W, and a small window air conditioner (5,000 BTU) consumes about 450W of electricity per hour.
A typical residential solar system ranges from 3 kWh to 10 kWh, with a 10 kWh solar system producing more than three times the electricity that a 3 kWh solar system can produce.
It’s important to remember that the surge output can exceed the operating output capacity. For example, the EcoFlow DELTA Pro has an output capacity of 3600Wh, which indicates that the system can support up to 3600Wh of continuous power. However, for high-consumption appliances that might require more power on startup, the DELTA Pro can achieve a surge power of 7200W.
The continuous and surge power output ratings are essential to consider when determining which battery will support your household energy needs.
How Much Electricity Does a Solar System Produce?
The amount of electricity produced by a solar system depends on several factors, including the size of the system, the efficiency of the solar panels, and the amount of peak sunlight the panels receive.
On average, a solar system can produce between 300 and 600 watts per panel. A typical residential solar system consists of many panels, producing several kilowatts of electricity (depending on your roof or other installation space).
The efficiency of the system is another consideration impacting the overall energy production. Most solar panels have a 15-20% conversion efficiency, although you can find more efficient solar panels, such as EcoFlow’s rigid solar panels, that reach 23% conversion efficiency.
The amount of electricity solar panels can produce also varies depending on the location and weather conditions. Generally, solar arrays in sunny locations generate more electricity than in areas with less sunlight. But even under overcast or rainy conditions, solar panels will still capture energy from the sun.
What Size Backup Battery Do You Need to Power a House?
When determining the size of the backup battery required for your home, it’s crucial to consider your household energy consumption. A household’s energy consumption depends on the number and type of appliances used — and for how long.
A small, portable power station like the DELTA 2 can power basic essentials such as lights, personal electronic devices like laptops and phones, and smaller appliances for a day or two. Bigger systems like the EcoFlow Whole-Home Backup Power Solution can power your entire home for a week or more, depending on the number of extra batteries you purchase and your home’s energy usage.
To estimate your energy consumption, you can average your monthly electricity bills or use a smart meter to monitor your usage in real time. Standard household devices and appliances that consume a significant amount of electricity include:
- Refrigerator (100-200 watts/hour for standard models, up to 700 watts/hour for high-end models with additional features)
- Electric oven (3,000 watts/hour for standard models, up to 5,000 watts/hour for high-end models with self-cleaning features)
- Microwave oven (700-1,200 watts/hour)
- Coffee maker (900-1,500 watts/hour)
Heating and Cooling Systems
- Air conditioner (depending on the size and type, can consume anywhere from 1,000-5,000 watts/hour)
- Heat pump (consumption can range from 1,000-5,000 watts/hour)
Lighting and electronics:
- Television (depending on the size and type, can consume anywhere from 100-500 watts/hour)
- Computer (depending on the type and usage, can consume anywhere from 50-300 watts/hour)
- Gaming systems (depending on the model, can consume anywhere from 100-300 watts/hour)
It’s important to remember that these are rough estimates, and actual energy consumption will vary depending on the manufacturer, usage patterns, and other factors. However, by accounting for the energy usage of these common household appliances, you can estimate the size of the backup battery required to power your home.
You can also invest in multiple battery sizes to serve different energy needs. For example, a DELTA Pro portable power station with a 3600Wh (expandable to 7200WH) capacity would be more suitable for household appliances, such as heating and cooling, refrigerators, lighting, etc. The EcoFlow DELTA 2 with 1000Wh would be more than enough for charging electronics and small appliances. You can mix and match to create a custom home backup power solution.
Also, calculating the best backup battery size should factor in energy consumption, the power outage duration, how many appliances you consider essential, and your budget.
Once you have a rough estimate of your total energy consumption and the blackout duration you want to be protected against, you can choose the right battery technology, output, and storage capacity to fit your needs and budget.
Factors That Influence Home Battery Life Expectancy
To determine how many years a home backup battery will last before a decline in efficiency, you need to consider the type of battery, number of cycles (meaning the number of times it’s discharged and recharged), and environmental factors like temperature, among others.
By understanding how these factors affect a battery’s lifespan, you can make an informed decision on the best home backup solution to invest in for your needs and usage patterns.
Battery chemistry can significantly impact the lifespan of a home backup system. Lithium-ion batteries, for example, have a longer lifespan and are far more efficient than lead-acid batteries. They have a lower self-discharge rate, meaning they can maintain their charge for extended periods.
The newest line of lithium iron phosphate batteries (LFP or LiFePO4), such as those used in EcoFlow’s Power Kits, expand on the advantages of lithium-ion batteries. Power Kits are most suitable for off-grid living in motorhomes or tiny homes. LiFePO4 batteries are more lightweight and compact than lithium-ion, making them easier to install and maintain. They also have a wide temperature operating range and are not affected by deep discharge cycles.
Lead-acid batteries are heavy and bulky and have a shorter lifespan than either type of lithium battery. They require regular maintenance and are more sensitive to temperature changes. As the price of lithium batteries continues to drop, most homeowners choose lithium ion or LFP battery technology for their home backup power solutions.
The number of times a battery discharges, known as usage cycles, also impacts its lifespan and continued efficiency. The more you use a battery, the less time it will last in chronological terms. It’s also important to note that deep cycling, which discharges a battery to a very low level before recharging, will also shorten the lifespan of lead acid and lithium ion batteries.
Lithium batteries usually have ratings for thousands of usage cycles. For example, many of EcoFlow’s portable power stations last for over 6,500 cycles. Depending on how frequently you use your backup batteries, it could take years to notice any decrease in functionality.
Lead-acid batteries are usually only rated for a few hundred cycles before they start to degrade. If you ever discharge a lead-acid battery below 50%, this will decrease its remaining usage cycles. A lead-acid battery backup may be cheaper upfront, but you’ll have to replace it much more frequently.
Temperature affects the performance and longevity of both lead-acid and lithium ion batteries. You should keep lithium ion batteries between 0-45°C when charging and between -20-60°C when operating to ensure optimal performance and prolong their lifespan.
When you expose lithium batteries to high temperatures, the performance decreases. High temperatures can cause the battery’s electrolytes to evaporate, leading to a decrease in the battery’s storage capacity and an increase in its internal resistance.
High temperatures can also cause the battery electrodes to degrade more quickly, reducing the battery’s overall lifespan. Additionally, high temperatures can cause the battery to become unstable, which can increase the risk of thermal runaway and potentially lead to a fire hazard.
Low temperatures can also reduce efficiency. At very low temperatures, the battery’s electrolytes can become thicker, which can increase the battery’s internal resistance. It can result in a decrease in the amount of electricity that the battery can produce and store. Additionally, low temperatures can cause the battery electrodes to degrade more slowly but can increase the discharge rate.
Frequently Asked Questions
A 10 kWh battery backup can power a house’s essential functions for at least 24 hours if you aren’t relying on AC or electric heat. The battery bank can power more electrical appliances and offer a prolonged backup power supply when integrated with a solar power system. A lithium ion or LiFePO4 battery will typically last for many years before it needs to be replaced.
Home battery backups are worth it for many reasons, especially solar batteries, which are far more environmentally friendly and less costly to operate in the long term than fossil fuel generators. Home backup batteries and portable power stations that charge using solar panels utilise clean and renewable energy sources. Traditional fossil fuel generators require regular maintenance, are very loud, and produce toxic emissions. Solar backup batteries are quiet and require little to no maintenance.
Finding the Right Home Backup Solution for You
Finding the right home backup solution depends on your specific needs and usage patterns. You must consider the power output and storage capacity required, the maximum charging capacity if using solar panels, and your household’s electricity consumption and usage patterns.
EcoFlow’s portable power stations and solar generators are ideal for meeting your home backup power needs. All of EcoFlow’s portable power stations and power kits support portable, rigid, and flexible solar panels, helping to reduce your dependence on the grid and contribute to developing a more sustainable future.