What type of battery to use for solar panels?
Solar energy production systems are composed of photovoltaic panels , fasteners , inverter Or micro-inverter , cables and electrical protections, and optionally a supervision system overall performance.
The sun's energy is collected by the panels and transformed into electricity, which passes into the inverter from which you can send electricity to your home, office or industrial area. ☀️
To optimize the self-consumption rate, that is to say the fraction of the energy produced that you are able to use locally, it is possible to add a battery . This will allow the storage of excess production for use at times of underproduction (e.g. at night). 🌃
There are many types of solar batteries. In this article, we will explain their usefulness, their sizing, but also present the different batteries that you can find on the market and in particular on oscaro-power.com .
What is a solar battery?
A solar battery stores the energy generated by your solar system.
In a self-consumption system connected to the public electricity network, the battery will be used to store excess production during the day for use in periods of production deficit. Instead of returning excess solar electricity to the public distribution network, the solar battery collects it for later use . When the battery is fully charged, the system usually returns the surplus to the grid. When it is used to compensate for a production deficit and its charge is depleted, then again your house draws the remainder from the public grid. ⚡️
In self-consumption, your home is systematically connected to the public distribution network . The battery is therefore not a necessity, but adding a battery can double the rate of coverage by solar of your electricity needs . If you are not connected to the network, a battery system is absolutely necessary. Coupled with solar panels, it can make you 100% self-sufficient. We then speak of stand-alone system . However, it is then important to work carefully on the respective sizing of the solar system and the storage in order to minimize the investment cost and optimize the longevity of the system.
To find out if your solar panels work in cloudy weather and during the winter months, we invite you to visit our blog post .
There are different topologies of solar systems with storage.
In the first case, the battery is connected to the home's electrical system with a dedicated inverter, called a battery inverter. In this architecture, the storage system is therefore relatively independent of the solar system. This is an alternating current coupling (called AC coupling). This topology allows a battery to be added to a system that was not initially designed to accommodate one. Low voltage batteries are generally used in such types (typically 48V nominal voltage). You can find this battery on the Oscaro Power website.
In the second case, the battery is coupled directly to the solar inverter, this is then a hybrid inverter and the battery is connected at high voltage. This is called “DC coupling” or direct current coupling. This coupling topology solar/battery system is becoming the most common, because it has the advantage of offering better performance and greater simplicity of implementation. However, the initial choice of inverter must have been made taking into account the evolution of the need towards the addition of a battery. At Oscaro Power, the Huawei battery kit corresponds to this battery technology.
The different types of solar batteries
Find out what type of battery is used for solar panels
Lead acid
For decades, lead-acid batteries are used as a reliable energy source for off-grid areas. They are typically inexpensive and relatively simple to implement .
Lead-acid batteries are attributed with high power and discharge current, but low energy. They take a long time to fully charge: for a satisfactory service life, they must be charged with low currents and not left in a discharged state.
In order to maximize their lifetime, it is also important to perform shallow cycles: around 20% of the capacity can be cycled daily. If you request more, it will be at the expense of the lifetime. Which implies an oversizing of the installed capacity
Finally, lead-acid batteries must be disposed of properly, otherwise they can be a problem for the environment due to the highly toxic nature of lead. However, fortunately, they are highly recyclable.♻️
Two types of lead-acid batteries are commonly used for solar panels: open lead batteries (whose sulfuric acid electrolyte is present in liquid form) and the sealed lead batteries (whose electrolyte is immobilized in a glass fiber or silica gel. They are called VRLA for valve regulated lead-acid = lead acid batteries regulated by a pressure relief valve).
There open lead battery is a reliable option, but it requires regular topping up with demineralized water and adequate ventilation to operate safely. The correct setting of the regulation thresholds for its charge and discharge is also relatively complex depending on the battery chosen. The sealed lead acid battery is equipped with valves for regulating gas release, it does not require maintenance or water top-up, nor significant ventilation. Although sealed lead-acid batteries offer sufficient flexibility for installation, their sensitivity to temperature can pose a problem for people looking for a permanent alternative to their mains supply.
Lithium-Ion
THE lithium-ion batteries have become the most popular choice to complement a self-consumption solar system. The development of this type of battery is related to its application in the electric car industry.
THE lithium-ion batteries have very interesting performances for a solar system in terms of efficiency, robustness at all charge and discharge rates, and cycle life. However, they must be coupled with a charge and discharge management system called BMS (battery management system) which will guarantee the longevity and above all the safety of the system.
This type of solar battery generally requires low maintenance and has a high specific energy with a long life . Compared to lead-acid batteries, lithium batteries usually cost more.
Lithium-ion batteries can provide more cycles than lead-acid batteries, making them ideal for providing auxiliary services to the grid.
One of the energy-saving features of lithium-ion that makes it a good option for a solar system is its high efficiency in terms of charge and discharge. These batteries also lose less capacity when they are at rest (they have a low self-discharge), which is useful in solar installations where energy is only used occasionally.
Other alternatives: Solar panel battery
Nickel-Cadmium
Nickel-cadmium batteries are characterized by low maintenance and tolerance to a wide temperature range. They come in different sizes and performance levels, with a good lifespan .
However, this type of solar battery has a high discharge rate and low energy density, making it a relatively poor choice for permanent off-grid power. In addition, it requires special disposal like lead-acid batteries, due to the danger that cadmium toxicity can pose to the environment.
These batteries are now only used in very specific applications with high temperature constraints.
Sodium / Nickel Chloride
Also called battery ZEBRA , the sodium-nickel chloride battery is highly recyclable and produces no emissions. It requires no ventilation or maintenance. Its high energy density makes it an excellent storage option. However, it operates at high temperatures, which induces a high self-discharge when not in use. It is therefore not at all proposed for residential storage. 🏠
If you would like guidance for your installation project or for choosing your solar battery, our customer service Oscaro Power will be happy to answer you.
