How You Can Select the Best Battery for Your Solar Energy System?

By: Jan Hajek | Date Posted: December 17, 2020

When assessing your solar battery for a solar energy system, it’s crucial to consider specific specifications such as its lifespan and power capacity. In this post, we will delve into the essential criteria for comparing various energy storage options, including different types of solar batteries.

How to choose optimal batteries meant for your solar panels

While choosing a solar panel battery, there are the following parameters that we need to consider.

Power and capacity

The capacity of your battery will tell how much electrical power has been stored in a battery. Usually, this value will be expressed in kWh. Most of the batteries used for residential use have separate modules that are stacked together to expand the capacity of the solar power storage systems.

So, in other words, battery capacity indicates its size. However, this parameter may not show the amount of power that you can withdraw from the battery at once. Therefore, you also need to consider the power rating.

Power rating is the amount of energy that can be offered by a battery momentarily. Generally, this parameter is indicated in kW.


Most of the batteries must always be kept charged to some level. Full discharging of the battery may considerably decrease its lifespan.

The parameter DoD signifies the amount of electricity that has been withdrawn from your battery. The higher DoD indicates more battery capacity can be used.

Round trip efficiency

This parameter defines in percentage the amount of electricity fed into the battery that will be utilized. For example, if your battery was charged with 5 kWh of power and if it can provide 4 kWh of power to be used, its round-trip efficiency will be 80%.


In most households, every day, the solar batteries will get charged and discharged. So, after some time, a battery may lose some of its ability to remain charged and get discharged faster.

All solar batteries will have a certain warranty for a specified amount of charge-discharge cycles or service life duration. Because of gradual performance degradation, usually, battery makers usually warranty the amount of a battery’s capacity that will be kept after its guaranteed lifespan.

So, the manufacturer will specify your battery’s useful life and the amount of original capacity that will be lost gradually.


Nowadays, solar batteries are manufactured by different companies, including carmakers and technology start-ups. Most technology start-up companies offer next-generation technologies, but they have concise track records.

Carmakers may be in the market for many years, and their batteries may have proven longevity; however, they are still using first-generation technologies.

It is your choice whether you prefer to buy batteries made by advanced start-ups or any well-established producers. You must evaluate the warranty offered by the company for each particular battery.

All these parameters will influence your selection and decide how long your battery will last for your application.

Types of solar batteries

You will also need to get familiar with the different types of batteries. Certain chemistries work better in specific environments and how they get applied influences their storage capabilities. For example, in large-scale solar energy storage applications, more than 80% of installations comprise lithium-ion batteries.

Common Solar Energy Storage Batteries

Lithium-ion batteries

In these batteries, lithium ions transfer between electrodes while charging and discharging. Extra materials like manganese, nickel, and cobalt are added to the cells, which impact the voltage, performance, and safety of the battery.

These batteries are costly compared to other kinds because there is a need to monitor the temperature and voltage. Lithium-ion batteries are popular because of their high charge/discharge efficiency, long life cycle, no maintenance, and lightweight.

Lithium-ion types

  • LCO or Lithium Cobalt Oxide – Small and stable, with limited load, and short lifespan. Popular for laptops and cell phone needs.
  • LMO or Lithium Manganese Oxide – No cobalt, so it has fast charging and enhanced thermal stability. Batteries can be applied to power tools and medical devices.
  • NMC or Lithium Nickel Manganese Cobalt Oxide – Manganese and nickel offer high energy and stability.
  • NCA or Lithium Nickel Cobalt Aluminum Oxide is similar to NMC batteries, but Aluminum offers more stability.
  • LFP or Lithium Iron Phosphates – Generates less heat, so there is no need for cooling or ventilation. A great option for indoor applications.

Nickel-based are reliable, rugged, and suitable for large-scale energy storage. Regular maintenance is not needed, but ventilation is necessary. Sodium-based are not explosive and function in a wide temperature range.

How You Can Select the Best Battery for Your Solar Energy System


Lead-acid batteries

Lead-acid batteries are the oldest form of storing energy. They are inexpensive and reliable. A lead-based grid is submerged in an acidic electrolyte, which needs replacement after a long time. The batteries are heavy and have a limited life cycle. In terms of charge and discharge, these batteries are inefficient.

Lead-acid types

  • Flooded – Need regular refills as electrolytes evaporate while charging. Needs an enclosure with sufficient ventilation to keep off-gassing levels low.
  • VRLA or Valve Regulated Lead-Acid – Batteries can be sealed, and off-gassing can be regulated with valves. VRLA can be categorized into the gel and absorbed glass mat [AGM]. The latter performs great in cold temperatures, and the former is good in warm conditions.

Flow batteries

Two chemical components are dissolved in some liquids and disconnected by a membrane. Both chemical solutions circulate in their specific space, while the electric current is generated via the membrane. The liquid energy sources create electricity.

Flow batteries can be applied for long-term storage, and it needs little maintenance. Rather than adding an extra storage system or battery units to increase capacity, add more electrolyte liquid in the flow battery system.

Flow types

  • RFB or Redox Flow Batteries – The system makes use of Oxidation reaction and chemical reduction to store energy within electrolyte solution.
  • Hybrid flow batteries – RFB qualities are used along with solid metal additives.

This brief description of different types of batteries will help you choose the best to suit your needs.


Thank you for reading!

Jan Hajek

I am an experienced writer. I write about home improvement topics such as construction, electrical work, plumbing, security and safety, interior design, exterior design, tools and woodworking, gardening, and garage organization. I love helping people improve their homes and make them more enjoyable places to live.

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