Shopping for a solar battery (or any energy-related product) can be confusing. There are a ton of different specs and metrics, and it’s often hard to tell which options make sense for your home.
Here are some of the most common questions we get about solar batteries, and our answers:
Are Batteries for Solar Worth It?
Solar batteries are a smart investment for most solar energy users, especially those who want to go off the grid. They are recommended for residential energy storage, DIY solar projects, and many other uses.
You can use your solar batteries to store the extra energy your system generates during the day. That way, it’s there when you need it at night or on cloudy days. Your batteries will also come in handy during power outages.
Storage systems for solar are an energy-efficient source of backup power for many people. However, they tend to pay off more in the long run — in the short run, a propane or natural gas generator may be cheaper.
How do battery storage systems work with solar panels??
You can install battery storage right alongside your solar panel system to store any excess energy produced. Then when your panels aren’t producing energy, such as at night or on days with less-sunny weather, you can use the energy stored in the battery instead. You may need to buy an inverter to convert the stored DC power in the batteries to the AC power you need for your home.
Not all residential solar panel arrays require battery storage. However, we often recommend them for homeowners depending on their energy needs and goals. In most cases, we recommend storage for reliable backup power protection in an outage.
A battery storage system can also reduce your carbon footprint, lower your utility bills, and even help you go off-grid, depending on the battery storage system chosen for your installation..
Batteries self-discharge over time, meaning the energy will deplete a little bit each month if it is not used. Newer batteries may deplete 1-2% per month, while older batteries may deplete the same amount over the course of a week. You may need to take self-discharging into account if you plan to store energy for long periods of time.
How Long Do Battery Storage Systems Last?
A fully charged solar battery should be able to power a home for 12 to 24 hours on average. Typically, a solar battery will last up to 15 years and most manufacturers offer a 10 year warranty.
Factors like the capacity of your battery system, your household’s energy consumption, and whether or not you are connected to an electrical grid affect how long your solar battery can provide continuous power. You can help your solar battery last longer with proper maintenance and protection from extreme weather conditions, including extreme temperatures. For that reason we always recommend having the batteries installed in the garage, but if they have to be outdoors, keeping them out of direct sunlight is best.
How Do I Choose the Right Solar Battery Bank Size?
A battery bank is a collection of connected batteries that allow for more power storage than you would get from a single battery. Your ideal battery solar bank size depends on the size of your solar array and the amount of power your household needs to store.
To figure out what size solar battery bank you need, get in touch with our Switch Electric team. We help people throughout the Seattle and Walla Walla areas with their solar energy goals.
How Do I Compare Battery Systems for My Home?
You can compare solar batteries by capacity, power, depth of discharge, round-trip efficiency, and warranty.
Capacity to power tells you how much energy the battery can store. It’s usually measured in kilowatt-hours (kWh). A typical capacity for a solar battery is 10 kWh, but some have a higher or lower capacity. On average, American households use about 30 kWh per day.
Power is the battery’s output capability, or the amount of amperage it can deliver at any given time. Some batteries can deliver more power at once than others. The power of a battery is typically measured in amps.
Depth of discharge (DoD) is how much your battery can be used before you begin to shorten its life span. A higher DoD means you will get more usage from the battery’s capacity.
Round-trip efficiency is the difference between the amount of energy used to charge the battery and the amount of energy available for you to use. The higher the round-trip efficiency, the better.
Warranty is not a top factor in every buyer’s mind, but it can make a huge difference over the course of your solar battery ownership. Battery performance tends to decline over time, and you ideally want a warranty that guarantees years of good performance and/or a large number of cycles. The warranty or guarantee should also cover the battery’s capacity.
What Types of Solar Batteries Are There?
Deep-cycle batteries are designed to maintain a steady flow of power over a long period of time. They can complete a discharge-recharge cycle several times, and they have thick lead plates to increase the lifespan of the battery. Lithium-ion, gel, and flooded batteries are all types of deep-cycle batteries.
Lithium-ion batteries were considered revolutionary for home energy when they first became available. This type of deep-cycle battery offers relatively high energy density, a long life span, low weight, easy installation, and low maintenance needs.
Gel batteries are another type of deep-cycle battery. They are often used in campers, vans, and boats because they don’t need to be kept upright.
Flooded lead-acid batteries
Flooded lead-acid batteries, also known as wet-cycle batteries, tend to be cheaper than most solar batteries but require more maintenance and monitoring. They contain liquid and disperse hydrogen gas, which makes them a more natural option for clean energy storage, but they need to be regularly refilled with distilled water.
Sealed lead-acid batteries
Sealed lead-acid batteries are a lower maintenance alternative to flooded lead-acid batteries. They prevent water depletion and gas dispersal by keeping the battery from reaching its gas-generating limit as it charges. Unfortunately, this characteristic means the battery will never be completely charged.
Lithium-polymer batteries are less likely to overcharge or leak electrolytes than most solar batteries. However, they are more expensive and tend not to last as long as lithium-ion batteries.
Nickel-cadmium, or ni-cad batteries, are one of the most durable types of solar batteries on the market. If they are properly maintained and fully discharged once in a while, they can have a very long lifespan. Potential buyers should be aware that cadmium is toxic, which means you cannot dispose of these batteries in a traditional landfill.
Saltwater batteries are a great option for those looking for even cleaner, more environmentally friendly energy. They use saltwater, a natural, nonflammable, and nontoxic substance, as an electrolyte. Best of all, these batteries last a long time with little to no maintenance.
- Lithium-ion batteries are a good all-around option for most homes.
- Gel batteries are a good choice for campers, vans, and boats.
- Flooded lead-acid batteries are a relatively cheap and natural choice, but they require more maintenance. Sealed lead-acid batteries are a lower-maintenance alternative that does not charge as fully.
- Lithium-polymer batteries are less likely to overcharge or leak electrolytes, but they’re more expensive and do not last as long.
- Nickel-cadmium batteries are extremely durable.
- Saltwater batteries are very clean, environmentally friendly, and low maintenance.
How Much is a Home Solar Battery?
The average home solar battery installation costs between $12,000 and $22,000. We recommend looking at the total cost per kWh for the amount of battery storage you need. In many cases, it may make sense to choose a few high-capacity batteries rather than a larger number of lower-capacity units.
Solar batteries cost what they cost because of the materials used to produce them. Over time, solar battery prices are expected to drop due to technological advances, although recently we have seen them rise due to shortage of materials and growing demand.
To find out how much a solar battery system will cost for your home, get in touch with a local solar energy expert. You can reach out to the Switch Electric team for electrical needs in the Seattle or Walla Walla areas. If you are looking to install a completely new solar system, check out our solar cost calculator.
What Are the Best Battery Storage Systems For Solar Energy?
Here are our top picks at Switch Electric due to the quality of materials and warranty that is offered:
- SunPower SunVault — offered in 13kWh, 26kWh, and 52kWh and featuring a 10 year unlimited cycle warranty.
- Enphase IQ Storage — offered in increments of 3.36kWh of battery storage that can be built up to a total of 40kWh depending on customers’ needs. This system offers generator support to help supplement charge to the batteries in extended outages. The warranty is 10 years or 4000 cycles.
Did We Answer Your Question?
For more information about solar batteries and solar power systems, get in touch with the Switch Electric team. We’re always happy to help people work toward a more renewable, reliable energy system.