Solar Battery Cost, Purchase, and Installation Explained
Solar battery cost falls between $135/KWh and $1,200/KWh. The variation in this cost depends on factors like battery type, size, capacity and installation conditions.
It is also important to note that the cost of installation differs from solar battery cost. Installation may cost as low as $200 or as high as $2,000. Again, this depends on different factors.
In this article, the cost of a solar battery is discussed extensively, according to the following outline;
Factors that Determine the Cost of Solar Battery
1). Capacity of the Solar Battery
Battery capacity refers to the amount of energy it can store [1].
On the average, a solar battery has a capacity of about 10kWh, with a range of between 3kWh and 20kWh.
The capacity of a solar battery is important because it directly affects how long the battery will be able to last while being used, and the magnitude of electric power-load which the battery can carry.
Solar batteries with higher capacity often have better performance, although this depends on the size of the solar system connected to the battery, and other conditions of use. Generally, higher battery capacity translates to longer backup periods during a power outage.
The following table outlines the average cost of a (lithium-ion) solar battery according to different categories of capacity;
| Battery Capacity (kWh) | Average Cost ($) |
| 3.0 | 900 |
| 8.0 | 3,500 |
| 10.0 | 4,500 |
| 13.0 | 9,000 |
| 18.0 | 9,000 |
2). Size of Critical Load
In most cases, a solar battery is not configured to handle the entire power load of a building of facility.
Rather, the solar battery could be configured to backup the 'critical load' of the building.
This critical load is usually comprised of the electric circuits and systems that are considered to be most important. These circuits and systems, are intolerant of power interruptions and must be maintained with power supply at all times [6]. Some examples of units which may comprise the critical load include lighting, and power terminals for essential devices.
While it is possible to backup an entire building with solar batteries, the critical load method helps to minimize the cost of battery installation and maintenance, by minimizing the number (and/or capacity) of batteries which are required.
In order to implement this type of backup, a critical loads panel is used. This is a sub-panel hardware device, which provides links to the important circuits which must be backed up by the solar battery(s).
The critical loads panel enables the power supply to switch to the critical load units when an outage occurs. By supplying power to these critical load units alone, the backup power in a solar battery is maximized.
However, the cost of solar battery purchase/installation will depend on the size of critical load. This implies that smaller critical load results in lower cost, and vice versa.
The main advantage of the critical load approach is that it saves the cost of using multiple solar batteries.
3). Mode of Power Supply
DC (Direct Current) and AC (Alternating Current) describe the two main types of current-flow or electricity [5]. These current-flow types also determine how power is supplied by a solar battery.
There are differences in terms of the cost of DC and AC solar batteries. In general, the AC battery costs more than the DC battery. This is due to factors that include performance, versatility, efficiency and production materials.
4). Tax Credits and Incentives
As part of measures to ensure sustainable development in many regions, the installation of solar systems is facilitated by tax credits and other incentives [3].
An example of such incentives is the solar Investment Tax Credit (ITC) which was enacted by United States government in 2006 [2] [4].
This scheme provides a 26% tax credit for solar system components (including the solar battery) which are installed in the United States between the years 2020 and 2022, as well as a 22% tax credit for solar systems installed in 2023.
The cost of a solar battery (in terms of both purchase and installation) will therefore vary according to the value of the tax incentive (if any) which applies.
5). Related Equipment
To install and efficiently use a solar battery, there are some equipment which are usually required.
Examples of such equipment include conduits and backup gateway. The cost of these additional components will affect the cost of solar battery installation.
6). Solar Battery Composition
Solar batteries can be categorized based on their internal composition.
The various types of solar battery, on the basis of this classification scheme, include lead-acid and lithium-ion, among others.
Lithium-ion batteries (which are most common) include Nickel-Manganese-Cobalt (NMC) and Lithium-Iron-Phosphate (LFP) types.
These two types differ in their chemistry, as well as their cost, with the LFP solar battery being generally more expensive than the NMC battery.
7). Current Conversion Process
Within this context, current-conversion refers to the process involving the change of DC to AC.
For a solar battery, the solar energy which is converted to electricity, is often stored in the form of direct current (DC). An inverter is needed to convert this direct current to alternating current (AC) which is needed by the system.
Some solar batteries have an inverter incorporated into them. Such solar batteries will cost more than others which have no incorporated inverter.
8). Solar System Age
A solar battery is itself one of the components of a solar system, alongside the solar panel and inverter.
The cost (of purchase and installation) of the solar battery will vary according to the time of installation of the entire solar system.
When the solar battery is simultaneously installed with the other components of the system, cost savings can be achieved, as there are usually minimal adjustments to be made with regards to the wiring and structural support of the overall solar system.
This is not the case when the solar battery is being installed as a retrofit component of a previously-installed solar system. In such a scenario, the cost of installation is higher, because the solar battery must be wired and configured carefully, to fit the existing system.
Other factors which affect the cost of a solar battery include depth of discharge (DoD); and efficiency.
Installation Cost of Solar Battery
The cost of installing a solar battery (or a set of batteries) may vary between $200 and $10,000. Exact values may exceed this range in some cases, and depend on the capacity of the solar battery, as well as the mode and conditions of installation.
Conclusion
The cost of a solar battery varies across a wide range. Factors that determine this cost include capacity, critical load, incentives, depth of discharge, efficiency and battery composition.
References
1). Bobby (2014). "How to Calculate Battery Capacity." Available at: https://www.upsbatterycenter.com/blog/calculate-battery-capacity/. (Accessed 8 March 2022).
2). Higgins, S. (2022). "3 Things to Know About the 26% Solar Tax Credit Before It's Gone." Available at: https://www.sunvalleysolar.com/commercial-blog/3-things-to-know-about-the-commercial-solar-federal-tax-credit. (Accessed 8 March 2022).
3). Murphy, L.; Pelchen, L. (2022). "Solar Tax Credit 2021 By State: What You Need To Know." Available at: https://www.forbes.com/advisor/home-improvement/solar-tax-credit-by-state/. (Accessed 8 March 2022).
4). Neumeister, K. (2023). "Federal Solar Tax Credit (What It Is & How to Claim It for 2023)." Available at: https://www.ecowatch.com/solar/incentives/federal-tax-credit. (Accessed 14 March 2023).
5). Peshin, A.(2022). "DC vs AC: Direct Current (DC) Vs Alternating Current (AC)." Available at: https://www.scienceabc.com/innovation/ac-vs-dc-alternating-current-or-direct-current-which-is-better.html. (Accessed 8 March 2022).
6). Weir, R. F. (2022). "Providing Non-Stop Power for Critical Electrical Loads."Available at: https://www.hsb.com/TheLocomotive/ProvidingNon-StopPowerforCriticalElectricalLoads.aspx. (Accessed 8 March 2022).
