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Choosing the Best Batteries for A Solar System

best batteries for a solar system
Table of Contents

Solar batteries are probably the most expensive piece of hardware in your solar system for storing your solar power. Therefore, it is crucial that you choose the correct battery for your solar power system. 

Many homeowners wonder – what are the best batteries for a solar system? Here are a few of our top tips and recommendations for the best batteries for solar.

Choosing the optimal solar storage solution will ensure you can effectively capture and store energy from your solar panels for use when the sun isn’t actively shining.

Evaluating aspects like battery chemistry, capacity, warranty length and ideal usage hours will enable you to invest in one of the best batteries for a solar system for your specific needs and budget.

How Do I Choose the Best Batteries for A Solar System?

When considering the best batteries for a solar system, there are a few different types of solar batteries for sale. Lithium solar batteries, currently the best batteries for solar battery storage available, tend to be more expensive. 

However, they have a longer lifespan, usually between 5000 & 10000 cycles depending on your battery management system. As you evaluate batteries for your solar power system, factoring in longevity, efficiency, and cost will enable you to invest in one of the best batteries for a solar system that matches your needs

Click here to browse our selection of the best lithium solar batteries for sale

When evaluating the best batteries for a solar system, gel lead acid batteries, sometimes referred to as gel batteries, are more budget-friendly.

However, they have a shorter lifespan compared to lifepo4/lithium batteries, usually only lasting for 1500-2000 cycles before efficiency drops. Another downside to gel batteries is lower efficiency – a 100 amp/hr gel battery will only deliver 60 amp/hour.

This lower capacity means when seeking the best batteries for solar energy storage, you may need to buy more lead acid/gel batteries to power your home during an outage. Still, gel batteries can be one of the best batteries for a solar system when affordability is the priority over longevity.

How Does A Battery Life Cycle Work?

As you use and recharge your battery, it gradually loses its ability to return to its original capacity. A battery’s life cycle is the number of charge and discharge cycles it can complete before losing performance.

Battery Capacity & Power

The total amount of electricity that a solar battery can store, measured in kilowatt-hours, is referred to as capacity (kWh). Most home solar batteries are “stackable,” which means you can combine multiple batteries with your solar-plus-storage system to increase capacity.

While capacity indicates the size of a battery, it does not indicate how much electricity it can provide at any given time. You must also consider the battery’s power rating to get the full picture.

A power rating in the context of solar batteries is the amount of electricity that a battery can deliver at one time. Kilowatts are the units of measurement (kW).

A battery with a high capacity and a low power rating would provide a small amount of electricity (enough to power a few critical appliances) for an extended period of time. A low-capacity and high-power rating battery could power your entire house for a few hours.

Battery Depth-Of-Discharge

The vast majority of batteries must be kept charged at some level at all times. The battery’s lifespan is significantly reduced when it is fully discharged.

DoD denotes the amount of electricity withdrawn from the battery. Many battery manufacturers specify the maximum possible depth of discharge for their products.

For example, a battery with a capacity of 10 kilowatt-hours and a depth-of-discharge of 90% allows for up to 9 kilowatt-hours of use before needing to be charged. The greater the depth of discharge, the greater the capacity of a battery that can be used.

Battery Round Trip Efficiency

The round-trip efficiency of a battery represents the amount of energy that can be used as a percentage of the amount of energy required to store it.

For example, if you feed your battery five kWh of electricity and only get four kWh of useful electricity back, the battery has an 80% round-trip efficiency (4 kWh / 5 kWh = 80%). In general, a higher round-trip efficiency indicates that you will get more economic value out of your battery.

Battery Life & Warranty

For the majority of home energy storage applications, your battery will “cycle” (charge and drain) daily. The battery’s ability to hold a charge will gradually decline as you use it more.

In this sense, solar batteries are analogous to the battery in your cell phone: you charge your phone each night so that you can use it during the day, and as your phone gets older, you’ll notice that the battery doesn’t hold as much charge as it did when it was new.

A battery, for example, might be warranted for 5,000 cycles or 10 years at 70% of its original capacity. This means that the battery will have lost no more than 30% of its original capacity at the end of the warranty. Your solar battery will be covered by a warranty that guarantees a certain number of cycles and/or years of service.

Because battery performance degrades naturally over time, most manufacturers will also guarantee that the battery will retain a certain amount of its capacity during the warranty period. As a result, the simple answer to the question “How long will my solar battery last?” is that it depends on the brand of battery you purchase as well as how much capacity it loses over time.

Battery Manufacturer

Various companies from automakers to tech startups now produce batteries, complicating choices on the best batteries for a solar system. An established automaker is likely to offer proven technology if not the latest advances. Meanwhile, a startup may boast a cutting-edge but less-tested product.

When assessing the best batteries for your solar system, weigh your priorities. Do you prefer an innovative but unproven battery to an agile startup?

Or a reputable name brand with a long history but a slower pace of innovation? Reviewing product warranties can provide insight when evaluating the best batteries for a solar system. Your needs and risk tolerance determine if trailblazing tech or tried-and-true is the top choice.

How Long Do Solar Batteries Last?

The first way to answer this question is to determine how long a solar battery can power your home. When your solar panels are not producing energy, a fully charged battery can often power your home overnight.

To make a more precise calculation, you’ll need to know a few variables, such as how much energy your household consumes on a daily basis, the capacity and power rating of your solar battery, and whether or not you’re connected to the electric grid.

The average South African household will use roughly 30 kilowatt-hours (kWh) of energy per day and a typical solar battery can deliver some 10 kWh of capacity. Thus a very simple answer would be, that if you purchased three solar batteries, you could run your home for an entire day with nothing but battery support. 

What Are the Best Batteries for Solar?

When considering the best batteries for a solar system, lithium batteries are currently top-rated but cost more upfront. Lithium solar batteries usually operate from 5000 to 10000 cycles. 

Comparatively, gel lead acid/gel batteries are more budget-friendly solar batteries but only deliver around 1500–2000 cycles before efficiency drops.

Lifespan is a key difference. While gel batteries for solar power systems are cheaper, their shorter usable timeframes mean more frequent replacement, impacting long-term value. Lithium batteries support lasting solar energy storage. 

Weighing budget, expected cycles, and replacement needs helps determine the best batteries for your home’s system. Though pricier, lithium batteries offer enduring performance – for many homeowners, the best batteries for solar investment.

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