How You Can Select the Best Battery for Your Solar Energy System?
By: Jan Hajek | Date Posted: December 17, 2020
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While evaluating your solar battery options, you must use certain specifications, e.g., how long your solar battery will last or the amount of power it can provide. Here in this post, we will consider all those criteria you need to do to compare different energy storage options and the type 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 are having 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The parameter DoD signifies the amount of electricity that has been withdrawn from your battery.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 gets 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 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 it gets applied influences its storage capabilities. For example, in large-scale solar energy storage applications, more than 80% of installation comprises lithium-ion batteries.
Common Solar Energy Storage 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 are lightweight.
- LCO or Lithium Cobalt Oxide – Small and stable, 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 in 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.
Lead-acid batteries are the oldest form for 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.
- Flooded – Need regular refills as electrolytes evaporate while charging. Needs enclosure with sufficient ventilation to maintain 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.
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.
- 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!