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Choosing the Best Battery For Your Solar Energy System

July 30, 2021

Battery storage has been a hot topic among many energy-conscious consumers. If you have a solar energy system installed in your home, you want to store the unused electricity for use during the night or non-sunny days. To store this energy for later use, you need to invest in solar batteries.

Since batteries are important to keep your solar system working, picking the best one sees you consider many factors in the decision-making process. These factors could include your budget, efficiency, battery capacity, and many others. Your choice of battery depends on your needs.

To help you choose the ideal battery storage for your solar system, this article explains different battery types in the market ideal for solar, how to compare your solar storage alternatives, battery type comparisons, and other factors.

The Hustle of Choosing the Best Solar Battery

Like many homeowners, you could shop for a solar battery with limited know-how. The battery marketplace has adapted to generalizing your needs, and that information is most of the time inaccurate. It is daunting to select an ideal solar battery, given the numerous types and brands out there. Many buyers buy one-size-fits-all batteries for their solar energy systems.

Is a one-size-fits-all battery ideal?

The reasons why buyers should not always choose one-size-fits-all batteries include:

  • Standardized solar batteries could be undersized or even oversized. Undersized batteries do not meet normal household power demand. On the other hand, oversized batteries cannot fully charge, especially in the winter season.
  • The solar batteries could be bulky size-wise. However, they often lack enough power storage capacity. The pricing of these one-size-fits-all batteries cannot justify the power capacity.
  • The technology on which batteries run is never indicated. Many one-size-fits-all batteries use lead-acid technology to store power. Many solar batteries in the market emphasize the technology they use.

While one-size-fits-all batteries are considered the right choice for many homeowners and business people alike, buyers hardly know the crucial considerations. These batteries trade various specs and features to meet the minimum requirement of various use cases.

Understanding Battery Types

Many homeowners and business people alike invest in solar energy without proper information regarding solar batteries. The battery types or technology used in manufacturing is an important consideration when choosing a solar battery. You also should consider your needs and budget when shopping for a battery. Below are the features of batteries in the marketplace and their ins and outs.

  1. Sodium-Nickel Chloride Batteries

The sodium nickel chloride battery uses unique chemistry, making it completely recyclable. The battery does not emit toxic elements and is not a fire hazard. Also, sodium nickel chloride batteries do not need complex cooling mechanics to perform. Scientists say that these batteries are safe and reliable as they can efficiently work at extreme temperatures of between -4℉ and 110℉. You also don't have to worry about the emission of hazardous elements.

The downside of sodium nickel chloride batteries is that they entail an 80% depth of discharge, and their lifespan is about 3,000 cycles. Speaking of the depth of discharge, as much as 20% of these batteries store power cannot be used. Lastly, installing sodium nickel chloride batteries is pricey, especially for residential and larger solar projects.

You could install sodium nickel chloride batteries in larger solar off-grid power installations or emergency power backup systems.

  1. Flow Batteries

Flow battery type is the newest entrant into solar battery manufacturing. The batteries use vanadium and bromine and water-based zinc solutions to store energy. Flow batteries are highly scalable. That means the battery’s output and capacity could be increased or reduced proportionally to the battery size. A feature that makes flow batteries stick out from other types is zero effects on the performance or life cycle of the battery due to deep discharge. The batteries have a very low self-discharge and a long lifespan. Another point to take home is that these batteries do not heat when in use.

While flow batteries have numerous advantages over many solar batteries, their production is expensive. The technology used in production has existed for decades, but only a handful of companies manufacture them. Another drawback is that these batteries are bulky and the lament used are toxic and corrosive.

Flow batteries are ideal for use in circumstances where the batteries charge and discharge many times daily, especially large-scale installations.

  1. Lithium-ion Batteries

Also known as li-ion, lithium-ion batteries have recently become popular battery storage. Researchers in the solar energy industry have not yet explored Li-ion’s full potential, but the technology is promising. You will find two types of Lithium-ion batteries, including nickel-manganese-cobalt (NMC) and lithium iron phosphate (LiFePO 4).

The NMC type is suitable for solar off-grid use because it has a high lifespan. Then again, LiFePo batteries work efficiently in extreme temperatures; hence, ideal for use in desert climates in other areas with extreme temperatures.

Lithium-ion batteries need no maintenance. These batteries entail a high battery energy density; therefore, they can store more energy than many other solar battery types of a similar physical size. Li-Ion batteries have longer lifespans due to longer life cycles and a high depth of discharge.  Scientists say that Lithium-ion can last for over 5000 cycles at an 80% depth of discharge. The lifespan of these batteries is 15 years. Like other battery types, Li-ion batteries have disadvantages, including they are expensive and very fragile.

  1. Lead-acid

For many years, lead-acid batteries have been the standard for energy storage. Invented in the 17th century, this battery is still widely used in solar energy systems. These batteries are widely used because they are affordable and cheaper to install than paying for a power mains grid connection. The only problem you experience when using lead-acid batteries is that they are bulky and work efficiently below room temperature.

Specifications You Need to Consider When Choosing Your Solar Battery

The solar battery market has studied users’ needs; hence, generalizing buyers’ expectations when venturing into solar power.  Every solar battery type is manufactured differently.  While some battery makers manufacture batteries using robots, others assemble them manually. The quality control level could affect battery quality.  Many manufacturers use heavier grids and lead, which affect the cells’ performance in the solar battery. Some companies test their products, while others don't.

Because of this, you find that batteries with similar features entail different lifespans and performances.  Choosing the ideal battery for your needs means the difference between poor and great system performance. Also, it means the disparity between high or negligible maintenance. Below and crucial considerations when buying a solar battery:

  • Battery Cost

Different solar batteries come with varying price tags. On average, solar batteries cost between $300 and $800 per kWh bringing the total battery costs to between $4,000 and $8,000. The actual costs could vary depending on the available brands and your location. The Federal Investment Tax Credit (ITC) offers incentives to homeowners looking to install solar systems in the US. As of writing this article,  the incentive for installing a residential solar energy system is 25%.

  • Battery Brand and Warranty

The marketplace is packed with different solar battery types and manufacturers trying to solve different solar battery issues. Each brand’s manufacturing and designing process is different; therefore, the final product is different. The brand is an essential consideration when buying solar batteries. Your budget and priorities determine if you buy a solar battery manufactured by a startup or a renowned battery manufacturer. Irrespective of your preferences, ensure you check the warranty details and pick the product that offers the longest guarantee.

  • Ambient Working Temperature

Ambient temperature refers to the average air temperature surrounding the battery.  It could also be the room temperature at which the battery sits. The rating shows the maximum temperature under which the solar battery can work efficiently. You don't want to ignore the battery’s ambient working temperature when buying one, especially if you reside in regions experiencing extreme temperatures.

  • Round-Trip Efficiency

Speaking of round-trip efficiency, batteries have the amount of energy that could be computed as the energy percentage used to store it. For example, if 100kWh of electricity is fed into a battery, and its optimum output is 90kWh, the battery’s round-trip efficiency would be 90% (90kWh/ 100kWh x 100). Always buy batteries with a higher round-trip efficiency because they are more economical.

  • Peak Power Output

Manufacturers categorize solar power batteries by their kilowatt peak (kWp). KWp refers to the peak power output of your solar system in ideal conditions. When buying a battery, the peak output rating shows the highest amount of power it could output at its best performance. It is recommended that you choose a battery with a higher peak power output rating.

  • Flooded Vs. Sealed Batteries

There are two classes of solar batteries, including flooded and sealed. Flooded batteries refer to the standard lead-acid batteries normally used in off-grid solar systems. These batteries are affordable, have longer lifespans, and you could easily service and clean them. When using them, these batteries release hydrogen gas.

Valve-regulated lead-acid (VRLA) batteries or sealed batteries cannot be maintained or serviced. A charge controller maintains the plates and fluids inside the battery to extend its lifespan. Sealed batteries do not release hydrogen gas.

  • Lifespan and Charge/Discharge Cycles

A battery’s lifespan is a major consideration when buying a solar battery. Battery makers try to outdo other competitors when designing durable batteries. The manufacturing process zeroes in more on making the battery resist cold and heat cycles for optimum performance. Also, the battery type technology is a factor that determines the battery lifespan.

Below are factors that could affect the longevity of a solar battery that you could check when buying one:

  1. Temperature — Chemical reactions inside solar batteries increase with temperature rise. To prolong your solar battery lifespan, you want to install them in a temperature-controlled room.
  2. Cyclic life — Cyclic life refers to the number of battery charge and discharge cycles. During normal use, flooded batteries will last for between 400 and 800 cycles.  Gel batteries could store and deliver peak power for up to 6000 cycles. Li-in batteries only last up to 300 cycles.
  3. Depth of Discharge — Depth of discharge refers to the extent to which the solar battery is discharged or used, given its capacity. Since solar batteries wear out over time, their capacity deteriorates too.
  • Battery Capacity

Universally, solar batteries are rated in amps or amp-hours. When picking a solar battery, remember that the indicated power rating is normally the fully developed battery capacity. That means the battery could take hundreds of charging cycles before it reaches full capacity. It could be misleading to test your battery only after a few charging cycles.

You don't have to comprehend electricity jargon to know your power needs or the ideal battery size. If you are already connected to the grid, you could seek an expert’s help to estimate your power consumption. When choosing your battery, knowing your power needs is crucial to pick a battery with enough energy storage.

Batteries with lengthy warm-up cycles are most likely to last longer than batteries with a high initial capacity before reaching full capacity.

Find a Solar Power Installer Near Me

Choosing the best solar battery for your solar system heavily depends on your power needs. More often than not, buyers do not have the right boxes to tick when shopping for a battery. If you don't know what to look for, you want to engage a solar installation expert.  They will guide you according to your daily power consumption statistics and recommend the ideal solar battery.

At Sun Solar Electric, we are devoted to providing you with the best solar power solutions that match your power needs. With many years of experience in battery technology, we could help you install the ideal solar energy system and a reliable battery storage unit. We will advise you on the batteries that suit your budget too.

Call us on 707-658-2157 if you seek quality solar power installation and services in Northern California and the Bay Area.

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