The Differences Between A Solar And Normal Battery


According to the US Energy Information Administration (EIA), solar power production will be the fastest growing renewable energy source by 2050. Considering the benefits on offer, Solar power’s growing popularity is justified. Although there is no doubt that solar power has disrupted energy production, we believe that the advent of affordable solar batteries can really transform how we power our homes. 

You may want to shift your solar power off-grid or you’re just curious about batteries and want to know the difference between solar batteries and normal batteries. Let’s discuss the differences and take a look at the pros and cons of each.

Is A Solar Battery Right For You?

Before we get into the nitty-gritty of batteries, it is important to know whether solar batteries are the right fit for your home. Most homes that have solar panels are also tied to their local power supply. Essentially what this means is that they can use solar power during the day when the sun is shining and the panels are generating electricity. But during nights, or days that are too cloudy, they can simply switch to the local power supply. 

However, with solar batteries, you can save the excess electricity generated and use it later. We will highlight a few reasons, why solar batteries might be the right solution for you. 

  • The Is No Local Power Supply – If you are living in an area with no power supply then getting solar batteries is pretty much a no-brainer. Having backup solar batteries gives you the ability to live completely off-grid.
  • Self-Sufficient Power Generation – You don’t have to rely on your local utility company for electricity supply. This gives you peace of mind particularly in disaster-prone areas, or areas with consistent power outages.
  • Lower Costs – One of the main advantages of having your own solar battery is the lower cost of power. One of the ways you can save costs is by not having to use grid power during “peak hours” when the rates are high. “Peak hours” are generally between 5 to 11 pm, when electricity demand is high.

    This can be a major problem in areas with high usage of residential solar panels. Electricity demand is very low during daylight, and then sharply increases as the sun starts to set. With power stored on your batteries, you will not have to worry about paying high rates during “peak hours”. 

    Installing solar panels is still a relatively large upfront investment. You basically, make up for your investment by paying less to your utility company and by selling excess electricity to the local grid. Having batteries protects your investment in case of the buyback rate changes or stops completely.

Differences Between A Solar And Normal Battery

All batteries work by using a chemical reaction to produce electricity when electrons move from one electrode to the other. Lead-acid batteries, essentially have a lead (negative terminal) electrode, a lead dioxide (positive terminal) electrode and use sulfuric acid as an electrolyte.

When connected to a DC system, the negatively charged sulfate ions move to the negative terminal. The excess negative ions then travel to the electrical device connected, before moving back to the positive terminal. 

This chemical reaction produces electricity and powers the electric device. It also produces water and lead sulfate, diluting the electrolyte. Charging the battery essentially reverses the process. The process of producing and storing electricity is almost similar for all batteries, even if the materials used are different. First, we will talk about normal car batteries and then move onto batteries specifically designed for solar power use. 

Car Batteries

Car batteries are basically lead-acid batteries and are also known as SLI (Start, Light, Ignite) batteries. These batteries are designed to produce short electrical bursts to start the car. After this, the car’s alternator takes over and powers all electrical equipment.

Car batteries use a sulfuric acid electrolyte with lead-dioxide plates. While perfect for producing short electrical surges, car batteries are not ideal for the provision of a constant, steady supply of electricity. 

SLI is the most common batteries used by automobiles and are part of the “wet-cell” category. Another form of “wet-cell” battery is “deep cell” batteries that provide long, stead discharge. Apart from “wet-cell” batteries, a second category is of dry batteries also known as VRLA battery. There are 2 main types of VRLA batteries, namely AGM battery and gel cell battery. 

Don’t worry, we will explain all of these terms and forms of batteries later on.

How Solar Batteries Are Different

Solar batteries are different, simply because they are intended for solar-powered systems. Although car batteries can be used to store electricity produced by solar panels, they are not ideal. Like we mentioned, most car batteries are SLI batteries and are simply not big enough to power a house. Secondly, these batteries are designed to produce short bursts of electricity instead of generating a steady supply of energy.

Solar batteries are deep cycle batteries, which means that they are able to dissipate electricity over long periods of time. The most common form of solar batteries is the lithium-ion battery. We will now list some of the popular solar battery types.

  • Lithium-ion – Lithium-ion batteries are the most common form of batteries that you see in everyday use from laptops and phones to solar-powered homes. Modern lithium-ion batteries have a lithium iron phosphate, positive electrode while the negative electrode is made from graphite.

    Negative lithium ions pass through the electrolyte to produce electricity. To learn more about how lithium-ion batteries work, click here.

    Lithium-ion batteries are relatively expensive but their long-term effectiveness makes up for the initial investment as they can last for up to 10 years. Apart from a long life span, these batteries are also quite light and smaller in size in comparison to lead-acid batteries.

    The cycle life of the battery varies depending on the model of battery but on average a lithium-ion battery has a cycle life of 5000 to 7000 cycles. Charging time is also relatively short. The batteries do not require maintenance although high temperatures can reduce the lifespan.
  • Wet Cell (Flooded Lead-Acid) – These are the cheapest batteries that you can buy for your solar-powered home and are rather similar to the normal car batteries. The downside of these batteries is that they can be quite space-consuming and heavy. It also requires regular maintenance as battery water needs to be added.

    You can expect your flooded lead-acid battery to last for up to 8 years with around 300 cycles. The time take to fully charge the battery varies, although it may take up to one whole day.

    Another problem with all lead-acid batteries is that the sulfuric they contain can be toxic and hazardous. Secondly, while low temperatures increase the capacity of these batteries, consistently high temperatures can lead to degradation. 
  • Gelled Electrolyte Sealed Lead-Acid – Gelled Electrolyte Sealed Lead-Acid is optimized for deep cycle use. The battery is sealed and does not allow gasses to escape; the battery’s electrolyte is held in silica gel. These batteries are cheaper than lithium-ion but slightly more costly than an AGM battery.  They also have the same size and weight as a similar capacity flooded lead-acid battery.

    The battery life is not great, ranging from around 2 to 5 years with more than 1000 cycles. Charging time is generally lower than flooded lead-acid batteries.
  • Absorbed Glass Mat Lead-Acid (AGM) – AGM batteries are similar to Gelled Electrolyte Sealed Lead-Acid batteries, except for the fact that the electrolyte is sealed within thin glass mats. The main advantage of AGM batteries is that they offer deep cycles without affecting its service life.

    Secondly, they can be charged very quickly, up to 5 times faster than the flooded lead-acid battery. Despite being more costly they are lighter than flooded lead-acid types of batteries. AGM batteries have an average life span of 4 to 7 years with around 800 cycles.

    By understanding the types and uses of solar batteries and normal batteries and how they work, you will learn to choose the right battery suitable for your needs. We hope this guideline was helpful.

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