9th November 2020
What Solar Battery is best to pair with my new solar panels 2020
  • BY : Ellen Ra
  • BY : Ellen Ra
  • 9th November 2020

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The Best Batteries For Your Home Solar Energy System

Solar panel systems have grown to be among the leading energy sources in the United States. The United States Solar Energy Industries Association has estimated that the solar power industry will become a 4.5 billion dollar market by 2023, doubling its size now with manufacturers such as Tesla Powerwall and LG Chem taking the lead. The growth of the solar energy industry has given rise to another renewable technology: the solar batteries that can be used to store extra solar power generated by the panels for further use. Companies such as Tesla and LG Chem have taken the lead in developing batteries like Tesla Powerwall and LG Chem RESU which can be fitted with solar panels to make a full home solar-plus-storage system. Most homes in the US have a solar panel system, and people are now looking to advance the system by installing batteries but are not sure how the solar-plus-storage system works.

How the Solar-Plus-Storage System Works

The traditional solar energy system for your home will include solar panels, equipment to mount solar panels to the roof, an inverter, and a monitoring system to track electricity production. The solar panel collects sun energy and turns it into electricity, which you use for your home. Most solar power systems are tied to the general grid. When your solar panels produce excess heat, it is fed back to the network, and in some states, you receive a credit that can be used on your utility for it. When the solar panels are not providing any electricity, you can use the credits instead of paying more for electricity bills. This process is called net metering. However, some states do not offer net metering, hence the need to install solar batteries.

Solar batteries store the excess electricity produced by the solar panels for future use instead of sending the power to the power grid. The batteries are charged by the excess energy produced by the solar panels. This energy is used to power the house at night-time and in the morning when the sun comes up, and the solar panels start to charge the battery again with the excess energy produced. Since the batteries stock the energy at your house, they offer backup power in case of an outage in your home area.

Things to Consider Before Purchasing Solar Batteries

Choosing the right batteries for your solar power storage system can be quite a hustle, especially if you are unsure what specifications to look for. The most important features to look for are; power and capacity, round trip efficiency, depth of discharge (DoD), manufacturer, and warranty.

Capacity and power

Capacity measured in kilowatt-hour (kWh) is the maximum amount of energy stored in the battery. Most residential solar batteries are designed in a way that you can pile them together with the solar panel system to get additional capacity. Capacity will only tell you the size of the battery, and the power rating will show you the amount of electricity it can produce at a given time. A power rating measured in Kilowatts kW is the amount of heat that can be delivered by your battery at one given time. A battery with a low power rating and a high capacity will provide a moderate amount of electricity to run some household appliances for an extensive period of time.

Round-Trip Efficiency

The round trip efficiency of a battery is the amount of energy used to store the battery. This is a percentage of the total amount of energy input compared to the total amount of energy output. For example, if you put in 5 kW in a battery and only 4 kW is useful energy back, then the battery has a round-trip efficiency of 80%. Batteries with higher round-trip efficiency will get you more economic value.

Warranty and Battery Life

As time goes by, batteries’ ability to hold charge gradually decreases, the more it is used, and you will realize that your solar batteries do not hold as much charge as they did when they were new. A warranty guarantees that the solar battery will be useful over a certain period of years, and they will keep a specific capacity within those years. Manufacturers such as Tesla and LG Chem also ensure that solar batteries can retain a certain amount of capacity over the time it’s under warranty. How long your solar batteries will last depends on the manufacturer and the capacity it will drop over time.

(DoD) Depth of Discharge

Batteries are required to retain some power at all times because of their chemical composition. If 100% of a battery charge is used, its lifespan will be significantly reduced. The Depth of Discharge refers to the battery’s used capacity before it requires to be recharged. Manufactures will put a specific maximum Depth of Discharge for ideal performance. For example, if a 9 kWh battery has a Depth of Discharge of 80%, you should use up to 7.2 kWh before recharging. A higher DoD means that you can utilize more of the battery’s capacity.

The Main Three Types of Solar Batteries

Solar batteries used for residential energy storage are made from three chemical compositions; Lithium-Ion, Lead-acid, and saltwater. Experts recommend using lithium-ion solar batteries for your solar panel system. However, other types of solar batteries can be more affordable, depending on your budget. Below are the three types of solar batteries that can be paired with your panels;

  1. Lithium-Ion solar batteries; if you are a homeowner, this is an excellent choice for your solar panel system. Most new home solar energy systems storage technologies use Lithium-ion as chemical composition. They are known to be exceptionally forgiving when it comes to the level of discharge they can tolerate. With this type of battery, you can go up to 100% depth of discharge and maintain an efficiency level of over 90%. This means that they have a higher Depth of Density, and lengthier lifespan compared to lead-acid solar batteries. Lithium-ion batteries are efficient, lighter, and compact than the lead-acid batteries; thus, they are more expensive.
  1. Lead-acid solar batteries; have been used for residential off-grid energy storage for over ten years. While they are the least costly solar batteries in the market, they have a lower DOD and a shorter lifespan than Lithium-ion solar batteries. Lead-acid batteries can be a better alternative for property owners who would like to install a lot of energy storage and go off the grid.
  1. Saltwater solar batteries; saltwater solar batteries are new in the residential energy storage market. Unlike lithium-ion and lead-acid solar batteries, saltwater batteries do not require heavy metals; they only rely on saltwater electrolytes. While other batteries need to be well disposed of with individual processes, saltwater batteries are recycled and are easy to handle. However, as a new and innovative technology, solar batteries made from saltwater, require some more testing for home use.

Solar Batteries Lifespan

The general lifespan range of solar batteries is between 5-15 years. You will only replace your batteries once to match your P.V. panels 25-30 years lifespan. Proper maintenance can have a substantial effect on the batteries. Batteries are significantly affected by temperature, ensure you protect them from sweltering and freezing temperatures. When a battery temperature drops below 30°F, it will require more power to reach maximum charge. If the same battery is overheating to over 90°F, it will require a reduction in cost. Many manufacturers, such as Tesla and LG Chem, have offered a solution for this by incorporating a temperature moderation feature in their LG Chem RESU Batteries and Telsa Powerwall batteries. However, for those without temperature moderation features, you can consider other options like earth-sheltered enclosures. Proper maintenance plays a vital role in the quality and lifespan of your solar batteries.

How long can solar batteries power your home?

Before purchasing a solar panel battery, most people wonder how long they last and if they can support a home’s energy needs when the sun goes down. In most cases, a solar battery will run your home throughout the night when there is no sun, and the solar panels are not creating any energy. However, there are variables you need to consider, such as how much energy your home uses in a given period, whether your solar power system is connected to the grid, and the power rating and capacity of your solar batteries.

To determine how many solar batteries you require to run your home, calculate the energy kilowatts-hour your household uses a day, and compare the number with the solar batteries capacity. Example According to the Energy Information Administration in the U.S , an American house will use average energy of 30 kilowatt-hours (kWh) per day, and an average solar battery can only provide 10kWh capacity. Therefore, you will require three batteries of 10kWh to run your household energy needs for a full day.

Solar panels will generate power during the sunny days and supply you for 6-7 hours per day. Most solar batteries, however, can’t operate at maximum capacity and be at 90% DOD. Thus you 10KWh solar batteries will probably have a useful function of 9 kWh.

If you are combining your batteries with solar P.V. array, you will need just one or two solar batteries to provide sufficient power to your home during night-time. However, if you do not have a solution for renewable energy, you might need to install three solar batteries or more to provide energy for your house for 24 hours. If you are considering complete disconnect from the grid, ensure you establish a few days’ worth backup systems to account for when there is no sun.

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Tesla Powerwall

Tesla Powerwall is one of the most advanced residential energy storage systems globally. Tesla is the leader in battery technology. Tesla Powerwall is a D.C. storage system with a capacity of 13.5 kWh per Powerwall. You can install multiple Tesla Powewalls for more storage capacity. The Tesla Powerwall reduces your dependence on the grid by storing energy for later use when there is no sun to power the panels. You can combine the Tesla Powerwall with other tesla products to cover any power outages and reduce household carbon footprint. You can connect this with an app that ill monitor your house’s energy consumption and production in real life. This allows you to control your solar power system from anywhere and set your preference to improve your energy independence from the grid, and outage protection.

Tesla Powerwall Technical Specs

  • Dust and water resistance to IP67
  • Tesla Powerwall meets the USA and international safety and EMI standards
  • Size L x W x D (45.3″ x 29.6″ x 5.75″)
  • Weight 114 kg / 251.3 lbs
  • Ten-year warranty
  • Energy Capacity; 13.5 kWh
  • Depth of Discharge 100%
  • Round Trip efficiency 90%
  • Power 5 kW continuous and 7 kW peak.

LG Chem Solar Batteries

LG Chem places a high priority on all its ESS products with a proven and fully certified global safety standard. Their cells have a total power of 9.8 kWh with usable energy of 8.8 kWh. Their batteries are compact and lightweight, designed to be mounted on a wall or the floor with insulation for both outdoor and indoor applications. LG Chem has reduced the installation time of their RESU battery by using simplified interconnections. LG Chem offers a ten-year warranty on the battery, and it can be used with SMA Sunny Island inverter. The battery is easy and fast to install with storage of up to 6000 cycles.

LG Chem RESU Batteries Technical Specs

  • Power rating 5kW
  • The usable capacity of 9.3 kWh
  • LG Chen RESU batteries have a DoD of up to 95%
  • Round Trip efficiency of 94.5%
  • Ten year LG Chem warranty with a guarantee of 60% capacity
  • Energy capacity 10kWh

When looking for your solar batteries options, you might encounter a lot of confusing and complicated product descriptions and specifications. The most important to use to assess the best battery for your home is the warranty, manufacturer, power ratings, battery capacity, and Depth of Discharge.

You Can Sell Surplus Energy Back To The Grid

With solar power, any surplus energy you may have, even with a battery storage system, can be sold back to the grid. There are 40 states in the country that allow for net metering. This means that homes that generating electricity by means of solar power systems are eligible to receive money by sending excess energy to power companies.

Of course, there are rules for selling electricity back to power companies, which vary by state and by the utility company. There are also limits to how much each household can sell back to power companies. How this works is that when you are not at home, the power generated by solar power systems is stored as credits. When you turn on the TV, AC, or anything else, you use those credits. If you create more power than you use, the excess can then be sold back to the utility company.

Creates Less Fossil Fuel Demand

When you generate electricity from your own solar panels or solar power system, you create less demand on the traditional electrical grid. When there is less demand on the electrical grid, this helps out others who are dependent upon the grid. When there are fewer people on the grid, those still on the grid don’t have to worry about brownouts or blackouts from too many people using electricity at once.

While those still on the grid have to worry about power getting knocked out for other reasons, less demand creates more supply. In economics, supply and demand figures into setting prices. Where there is high demand, this creates higher costs. With this model, fewer people on the grid creates less demand. Electrical prices should go down, which saves people money. Those people would have more money to switch over to solar power, thereby creating even less demand.

The California solar industry is currently thriving and homeowners can enjoy peace of mind when they purchase their solar panel systems. With 25-year warranties on every part of the system and 40-year workmanship warranties, homeowners can have peace of mind when purchasing their solar power system.

There’s a surplus of installers in California with low-interest rates and zero down financing. This makes now the perfect time to install solar panels on your home. Lower to no electricity bills, tax rebates and tax credits, and higher home value? What are you waiting for?

Thank You so much for your time,

Ellen Ra
Love Solar Energy

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