How To Choose a Home Battery Backup System?

Home battery systems are more than just a source of backup power, they’re a step towards true energy independence and the only way to acheive around-the-clock sustainable solar energy. A good home backup system ensures your most critical appliances remain powered during outages, while further offsetting expensive on-peak grid energy with clean solar electricity - even when the sun goes down. 

If you’re considering home battery storage, this guide will help you choose a system that meets your needs. We’ll look at what home battery backup is and how it works, types of batteries, the benefits of battery backup, things to consider when choosing a home battery backup system, and how to choose the right battery size for your home.  

What is home battery backup?

A home battery backup system stores energy to use during power outages or to further offset grid  energy consumption during peak hours or when the sun goes down. Home batteries are usually integrated with solar power setups, i.e. a solar battery, but they can also be charged from the grid. There are various levels of home battery backup, capable of powering homes from several hours to several days. 

How do backup batteries work?

How a home battery backup system works will depend on how it’s connected to your home’s electrical network. Here’s an outline of the basic process: 

• Step 1: Charging the battery: Home batteries can be charged in two ways: 

• From solar panels: If your home battery is part of a solar power system, it’ll be charged during the day using excess power generated by your solar panels. 
• From the grid: If you don’t have solar panels installed, or there’s not enough sunlight to generate power from your panels, the battery will be charged using electricity from the grid. 

• Step 2: Using stored energy: During power outages, your home battery system will automatically kick in to provide electricity. 

• Step 3: Monitoring energy usage: While using a home battery, you’ll be able to keep track of energy usage and battery status through the monitoring system. This keeps you in the loop as to how much energy you have stored and how it’s being used.

• Step 4: Recharging: If you have solar panels, your battery will charge during daylight hours using any excess solar energy that your home doesn’t need. If your battery is set up to charge from the grid, it will automatically begin charging once grid power has returned, and in accordance with whatever charging schedule has been programmed by the homeowner or the installer. 

Types of battery backup systems

There are three main types of batteries used for home battery backup systems: lead-acid, lithium-ion, and flow batteries. To help you understand which might be best for your needs, let’s look at each of these battery types and their pros and cons. 

Lead acid batteries

Lead acid battery types are the oldest type of rechargeable battery, made from lead plates immersed in sulfuric acid. Although their usable capacity is about 50%, lead acid batteries are affordable and durable, making them a popular option when it comes to home backup power solutions. 

If you opt for a lead acid battery, be aware that it requires more careful monitoring of charge levels than lithium-ion batteries. They’re also nowhere close to lithium-ion when it comes to efficiency, energy, and lifespan.

Pros of lead acid batteries: 

• Less expensive than other types of home batteries
• Long history of reliable performance
• Established disposal and recycling processes. 

Cons of lead acid batteries: 

• Shorter lifespan than other batteries
• Slow charge cycle
• Lower energy density, meaning they're bulkier and heavier than lithium batteries of the same capacity 
• Require regular maintenance 
• Shorter warranty. 

Lithium-ion batteries

Lithium-ion batteries are a newer technology that offers ultra-high charge rate efficiency. While more costly than lead acid batteries, they have a usable capacity of around 90%, allowing you to maximize energy use. Lithium-ion batteries are easier to maintain and have a longer lifespan than lead acid batteries and integrate well with solar power systems. They’re quickly becoming the standard in home battery backup systems. 

Pros of lithium-ion batteries:

• Longer lifespan due to a higher cycle life that lasts several thousand cycles
• High energy density, making them more compact and lightweight 
• Generally maintenance-free 
• Can be discharged at 80-90% capacity
• Tolerant of high temperatures
• Faster charging
• Can last 10 years or more when used daily. 

Cons of lithium-ion batteries: 

• Higher upfront cost 
• They must be recycled to prevent hazardous waste disposal, but recycling processes are still in their early stages and need improvement. 

Flow batteries

Flow batteries are less common in residential systems, however they show promise as an alternative to lithium-ion and may be used more frequently in the future. These types of batteries store energy in liquid electrolyte solutions which flow through a cell stack to charge and discharge. The most common types use vanadium ions or zinc bromide. 

Pros of flow batteries: 

• Can be discharged to 100% of its capacity
• Works well in high temperatures
• Recycling is relatively easy
• Long lifespan of 10+ years or more
• Maintains capacity over time. 

Cons of flow batteries: 

• Currently more expensive than lead-acid and lithium-ion batteries due to being an emerging technology 
• Don’t operate well in cooler temperatures below 59°F
• Require regular maintenance. 

Why get battery backup for your solar system

If you’re on the fence about investing in a home battery backup system, let’s look at the benefits they can provide. 

Cost savings

Home batteries can help you save money by reducing your energy bills. Many utilities use time-of-use pricing plans, which means that electricity costs more during peak demand periods. By storing energy during off-peak hours, when electricity rates are lower, and using it during peak times, you can avoid higher electricity rates and save money over time. 

Energy independence

Being able to generate and store your own electricity makes you less reliant on the grid and increases your energy independence. This makes you less vulnerable to fluctuations in energy prices and potential supply issues. Ultimately, home batteries - especially solar-powered batteries - give you more control over your energy usage and make your home more self-sufficient. 

Uninterrupted power supply

One of the main benefits of a home battery backup system is that you can continue to access power during outages. In the event of a blackout, your home battery will automatically kick in to power essential appliances and systems, like refrigerators, medical devices, and heating or cooling systems. This provides peace of mind during emergencies and ensures your home keeps comfortable even during extreme weather or natural disasters.

Increase property value

Investing in a solar power system with battery backup can increase your home’s value. Many homebuyers value renewable energy systems, not only for their environmental friendliness and reliable source of power but also for the cost savings they provide. The National Renewable Energy Laboratory (NREL) has already demonstrated that home value increases by $20 for every $1 saved on utility bills. Another study found that homebuyers were willing to pay an additional $15,000 or more for a solar-powered home. 

Maximize solar energy use

Solar power is a big investment and batteries allow you to maximize the use of your solar energy. Instead of sending excess solar power back to the grid, you can store it in your battery for later use during evenings or cloudy days. This ensures you get the most out of your solar investment. 

Environmental benefits

By storing excess solar energy and using it to power your home, you’ll be reducing your dependence on fossil fuels and lowering your carbon footprint. This helps decrease greenhouse gas emissions and pollution, contributing to a cleaner and more sustainable future. You won’t just be doing good for yourself, but also for the environment. 

Things to consider when choosing a home battery backup system

Below are some important things to consider when choosing a home battery backup system. Keep these in mind to ensure you select a battery backup that supports your needs and energy goals. 

Battery capacity

Solar battery capacity determines how much energy a battery can store in kilowatt-hours (kWh). When choosing a home battery, consider your household’s energy needs and ensure the battery capacity can support essential appliances for a reasonable period of time. Batteries with a larger capacity will provide power for longer, but they’re likely to be more expensive. Depending on your needs, you might choose to invest in one large battery or several smaller ones. 

Be aware that, in most cases, you cannot use all stored energy at once. Depending on the type of battery you’re using, completely discharging it can cause damage. Instead, you’ll want to look at the depth of discharge (DoD). Lead acid batteries, for example, have a DoD of around 50%. This means that, to avoid damaging the battery, you shouldn’t use more than 50% of its stored power. Lithium-ion batteries, on the other hand, have a DoD of around 90%, meaning you can drain most of the battery without causing damage. 

Cycle life

A battery’s cycle life refers to the number of charge and discharge cycles it can take before its capacity begins to decrease. A higher cycle life means a longer-lasting battery. Lithium-ion batteries are known for having a high cycle life that can withstand a higher amount of charge and discharge cycles compared to lead acid batteries. Depending on the manufacturer, you can find lithium-ion batteries with a cycle life of 2,000 to 10,000 cycles. 

Choosing a battery with a high cycle life is especially important if you plan to use your home backup system frequently. Note that cycle life can be influenced by various things, including depth of discharge, charging and discharging rates, temperature, and how well you maintain and manage your battery. 

Recharging options

A key consideration when choosing a home battery is whether you plan to charge it through solar power or the grid. If you have a solar panel system, choosing a home battery will be easy as many are designed to work seamlessly with solar power. If you don’t have a solar system, you’ll have to choose a battery that supports outlet charging. 

Efficiency

A battery’s efficiency indicates how much energy is lost during charging and discharging. Higher efficiency means less energy is lost, providing you with more usable power from each charge cycle. This equals less energy waste and better long-term performance of your batteries. 

Smart features & remote monitoring

Many new home battery systems come with smart features and remote monitoring capabilities. These features provide real-time insights into energy usage and battery status through a smart home panel or smartphone app. You can even receive alerts to manage or optimize the performance of your system, maximizing energy savings and keeping your battery healthy. 

Compatibility with solar power

If you already have a solar power system installed, it’s essential that you have an inverter that can work with solar batteries, i.e. a hybrid inverter. These inverters are designed to seamlessly connect and manage the flow of energy between your solar panels, battery, and the grid. 

Safety features

Home battery backup systems store significant amounts of energy and safety is a crucial element that shouldn’t be overlooked. When choosing a backup battery, look for those that have features that offer protection against overheating, overcharging, and short circuits. Be sure they are certified to meet industry safety standards and have undergone rigorous testing. 

Price

As with any investment, price is an important consideration with choosing a home battery system. The total amount you can expect to spend on a backup system will depend on how much energy you intend to store and whether you’re adding the battery to an existing solar power system or a new one. 

When weighing up price, take into account the battery’s capacity, cycle life, efficiency, and potential savings on energy bills. While cheaper options might be tempting, they might not offer the best long-term value. Generally, the US Department of Energy estimates solar batteries to cost between $12,000 and $22,000 depending on their size. Remember that part of this investment can be offset by solar tax incentives, such as the 30% energy storage tax credit that can be applied to stand-alone solar battery systems with at least 3kWh capacity.

How to choose the right battery size

One decision you’ll have to make when choosing a home battery system is the battery size. This will depend on various factors, including: 

• The size of your solar power system
• Your electricity consumption habits & energy usage patterns
• Whether you want energy backup during a power outage 
• Future changes (e.g. changing from gas to electric water heating)
• Budget & financial constraints. 

If you don’t already have a solar power system installed in your home, we recommend reaching out to a reputable solar installation company. They’ll help you calculate your average daily electricity consumption habits and recommend the best solar system and solar battery size to meet your specific needs and energy goals. 

Summary: Choosing a home battery backup system

Choosing the right home battery backup system involves weighing up your needs, goals, and usage patterns while also taking into account battery capacity, cycle life, efficiency, and other factors. With the information we’ve outlined in this article, we’re confident you’ll make an informed decision that meets your needs. 

If you’d like expert help choosing a home battery that integrates with a new or existing solar power system, the team at Sun Valley Solar Solutions would be happy to help. We can guide you through different home battery options, help you set up your backup system, and ensure you get the most out of your renewable energy. Contact us today for a free, no-obligation consultation. 

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