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Best Solar Batteries: 2023 Solar Battery Guide

Best Solar Batteries: 2023 Solar Battery Guide

Our list of the best solar batteries available in 2021

Thad Warren
January 2023
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5 Minutes

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Making smart energy decisions not only helps the environment and your wallet. Solar panels help you minimize your environmental footprint and be energy efficient. However, did you know that just having solar panels, doesn't give you the whole energy picture? You could still be creating large spikes in power that are increasing your bills. Batteries can assist in managing your energy even further.

How Do Solar Batteries Work?

Batteries enable you the flexibility to manage your energy to fit your needs.

Batteries allow the user to store the excess solar energy rather than sending it back to the power grid. In other words, if the energy produced is more than required for the building, it can be used to charge the battery. The stored energy can be accessed whenever it is required. Rather than just when it is available like when the sun is shining. When the battery is full and there are no building energy requirements the owner can still send electricity back to the grid to receive credit. If there is not enough sun shining and not enough energy stored, the building can still draw power from the grid.

There are a few different battery discharge methods. The best method for you depends on the type of utility rate you have and when you use energy.

The most common method is to reduce the energy pulled from the grid as much as possible and to flatten the building profile to reduce peaks in power.

Use EnergyBot’s Solar Calculator Tool

Choosing one solar battery amongst numerous is not an easy feat for any homeowner. To help you navigate this daunting task, use our solar calculator that enables you to make the right decision for your home. Note that choosing the best solar batteries will require checking the capacity to ensure it meets your household's energy needs.

Choosing the Best Solar Batteries for Your Home: Factors to Consider

There are numerous factors you must consider before deciding on one battery. What should you take into account?

  1. The battery capacity. It refers to the total amount of electricity it can store, generally measured in kilowatt-hours (kWh). 
  2. The battery life is important, but so is the warranty, as the performance is bound to deteriorate over time. With a warranty, you can be worry-free as you know that good performance for numerous cycles is guaranteed. 
  3. The depth of discharge (DoD) is another factor you must consider, as it indicates the amount of battery capacity that has been utilized. Aim for a high DoD, at least 40% or higher, to give you more usage from the battery. 
  4. Look for a higher round-trip efficiency (80%), as it is more economical. 

Types of Solar Batteries: Lead-acid and Lithium-ion

Lead-acid and lithium-ion batteries are the most common solar batteries for residential households. 

Lead-acid batteries are:

  • less expensive
  • have larger dimensions
  • lower DoD
  • need to be recharged more often

You should also note:

  • If you want a backup solution to prepare for a power outage, lead-acid batteries are a decent choice, but not a great option if you want to power your house daily. 
  • Flooded lead-acid batteries require regular maintenance and water refilling every one to three months.
  • Sealed lead-acid batteries don’t require maintenance as they never completely charge to avoid gas dispersal and water depletion. 

Lithium-ion batteries are considered to be the best solar batteries because they are:

  • smaller
  • lighter
  • have longer DoD
  • come with a minimum lifespan of 10 years
  • lower maintenance compared to most of the alternatives in the market.

Best Solar Batteries:

If you’re confused about which battery is right for you, here are some popular options that may work for you:  

  • Tesla Powerwall 2: It is a full AC lithium-ion battery system that has an inverter built-in, and offers a usable capacity of 13.5 kWh, making it the best in the market. In addition, it is compact, has high energy density, and can be easily fitted into any solar system. However, it is on the pricier end and can cost $10,000 on average.
  • Sungrow SBP4K8: One of the best solar batteries for in-home solar systems, the Sungrow SBP4K8 is developed by Samsung and retails for around $4000. It is easy to install and transport as it is fairly compact. It comes with a 10-year warranty. The installation process is easy and quick due to numerous cable entry points, and it claims to offer roughly 6,000 cycles. 
  • LG Chem RESU-10: The LG Chem RESU-10 is sized at 9.8 kWh, providing 90% usable capacity. This battery maximizes long-term reliability as the cells are layered in a pattern that prevents failure. It comes with 4,000 life cycles and a 10-year warranty. 
  • BYD Premium HVM: Available in two different voltage levels, the BYD Premium HVM performs well even at high-energy temperatures because of the cobalt-free lithium iron phosphate battery. If you want to increase the total capacity, you can stack the battery modules. The battery provides 3,000 cycles and comes with a 10-year warranty.
  • Powerplus Energy LiFe: The Powerplus Energy Life is considered one of the most durable batteries as it uses lithium iron phosphate cells. The battery offers 3.3 kWh and 100% usable capacity. It is priced at $3,500 and is affordable as compared to other brands. It also comes with a 10-year warranty. 

Make sure to do your research and compare different options to utilize your solar system to its optimal potential. A typical battery will last you 5-15 years and if you wish, you can extend its lifespan by protecting it from extreme temperature drops. For example, the Tesla Powerwall 2 comes with a built-in temperature moderator. 

Don’t forget, that utilizing EnergyBot’s calculator tool will help you get clear about what your home needs out of a solar battery. Depending on your energy usage, it can help you save a lot of money, reduce your environmental impact, and live entirely off-grid if you wish to! 

How Do Batteries Affect a Building Profile?

Let's take a look at how batteries work with some visuals. Below is a graph representing what a typical residential energy load profile looks like. 

Keep in mind that everyone's load profile looks different. It is dependent on many factors including location, weather, building construction type, the size of your building, the number of people, the type of energy-consuming equipment, and when the equipment is being used.

Energy-consuming equipment includes everything from lights, HVAC, appliances, and anything else that uses energy to operate.

The Basic Load Profile

The horizontal axis shows the hours of the day. The vertical axis represents energy. For this example, we aren't using real data and are only concerned which how the energy profile changes. The actual energy values aren't important. 

First, let's note that there is a baseline load. During the night some equipment will always remain on. A refrigerator is a great example of something that remains plugged in and pulls a constant amount of energy. Nightlights, charging your tech, and other small miscellaneous plugins could be pulling a small amount of electricity.

This is a small household, it is only a couple, let's call them Logan and Fiona. They have a dog named Teddy. 

Fiona wants to be environmentally conscious and comfortable. She set up their thermostat to turn on their HVAC system at 4 am every morning. The automatic schedule is both convenient and energy efficient because they no longer need to remember to turn it off. They also get out of bed at a comfortable temperature.

Logan and Fiona wake up at 5 am every morning to Teddy jumping on them for his morning walk. Since the sun isn't up yet, the first thing Logan does is turn on the light. He doesn't want to trip over Teddy's leash that was dragged into the bedroom.

The hallway and bathroom lights are turned on next. After walking Teddy, Fiona and Logan's morning routine consists of making breakfast, watching the morning news, and checking some emails before heading to work at 7 am to arrive at 8 am.

Since Teddy is home by himself for the day, Fiona and Logan keep the HVAC running to make sure he is comfortable too. Though some lights and appliances have been turned off, the curve in the middle of the day shows the curve of the HVAC system. The HVAC system follows the temperature changing as the day heats up with the sun.

Fiona and Logan both arrive home at 6 pm. After taking Teddy for another walk, Fiona begins to vacuum Teddy's hair he has shed on the rug and couch. Meanwhile, Logan makes dinner in the kitchen utilizing the stove, microwave, and rice cooker. After vacuuming, Fiona puts some clothes in the washing machine before dinner.

Dinner is ready and it's time to enjoy their favorite show. When they are done, Logan cleans up the table and turns the dishwasher on. Happy and full, the family heads to bed at around 10 pm.

solar-battery-load-1

 

Adding Solar

This image shows the typical shape of the energy generated by solar panels on a sunny day. 

 

solar-battery-load-2

 

When Logan and Fiona installed the solar system, they immediately saw savings on their utility bill. They even received an energy credit from the utility company. However, their energy bill wasn't zero. They have been hearing about how people are installing batteries in their homes. They wonder if there is more they can be doing.

 

solar-battery-load-3

 

The below graph shows how their energy profile has changed after installing the solar system. Their energy consumption has been greatly reduced in the middle of the day. There is also an over-generating credit. However, you can still see the two highest peaks haven't been affected by the solar system. The peaks occur before or after the sun is shining.

How your utility bill charges for electricity depends on the size of your home and where you are located. Each utility company has a different utility rate and method for charging. Nonetheless, there are two main types of charges you can see. One is for the peak power demand and the second is for the total amount of energy consumed. 

Fiona and Logan's peak power demand occurs at around 8pm. Their total energy consumption is equal to the shaded area under the curve. 

solar-battery-load-4

 

With the addition of solar, they have reduced their energy consumption but they haven't changed their peak power charge. It is also called peak demand.

Adding Batteries

Fiona and Logan have decided that with some government incentives (insert article to Inflation reduction act) they will be able to afford batteries to further reduce their electric bill.

Logan wants to increase the size of their solar array. He wants the biggest and baddest system on the block. Fiona likes the idea of being net zero and not using any electricity from the grid, but questions whether it's really necessary.

After talking with an Energy Engineer, they discovered they wouldn't be able to afford to be net zero. Purchasing more PV panels and a battery big enough to cover all of their energy is out of their price range. It is more cost-effective to "peak shave", not get more solar, and only purchase a smaller battery.

The below image shows how their energy profile changed after adding batteries with a peak shaving discharge method. 

solar-battery-load-5

 

By comparing image #6 to image #3, you can see how the excess solar has moved. Instead of going back to the grid, the excess solar was used to charge the battery. Then the battery "shaved" the two highest peaks down to the same level.

solar-battery-load-6

 

The battery hasn't reduced the energy consumption as much as the solar system but it is still reducing their utility bill. This method will reduce their bills because of how they are being charged by the utility company. Peak demand charges are separate from energy consumption charges.

Managing Your Energy Profile

By comparing the changes in Fiona and Logan's energy profile, you can see how their routines, solar size, and battery strategy can affect their energy consumption. Adding batteries to your home or building is great example of energy management.

solar-battery-load-7

 

solar-battery-load-8

 

solar-battery-load-9

We understand that this process can be overwhelming and confusing. There is not one right answer for everyone. If you are looking for your business, or you work from home, your energy profile can look vastly different.