How to choose batteries for photovoltaic
What are the costs and how do I pick the best PV batteries with storage?
We deal with batteries, one of the key components of a solar system's storage system. Let's look into more detail about the price of solar storage batteries, how they function, and the many varieties that affect not only the ultimate cost but also, and particularly, the system's efficiency. Photovoltaic storage batteries are one issue that needs to be carefully considered since it is quite delicate.
What are the uses of solar batteries?
Let's start by clarifying that the solar system's batteries are not the storage system; rather, they are a component, one of the most crucial but not the only one. In essence, these are the parts where the solar energy generated by the PV system is stored and then used as needed.
In this way, it is possible to achieve so-called energy independence by storing more energy during the day than you consume and, particularly at night, utilising that energy while waiting for the batteries to be recharged by the sun the next day.
Which battery kinds are there?
Batteries for solar systems come in a variety of varieties. They differ in terms of size, power, lifespan, yield, and efficiency in addition to the type of material from which they are produced. Lead-acid, lithium-ion, and nickel batteries are the most widely used types of batteries.
Benefits and drawbacks of the most popular PV batteries
Let's go more detailed by quickly contrasting the advantages and disadvantages of each type of battery for PV systems.
Although lead-acid batteries are the most affordable and long-lasting, they are also the heaviest, bulkiest, and have the shortest lifespan (generally between 3 and 5 years).
On the other side, lithium-ion batteries are more expensive but also have a longer lifespan (sometimes about 10 years), higher performance, and increased safety.
Nickel batteries can be produced in addition to metal-hydride (NiMH) or cadmium (NiCd) batteries. In both situations, the batteries have a much longer lifespan (even more than 20 years), the ability to function even in very low temperatures (the cadmium ones), or a greater capacity (the metal-hydride ones). These batteries, as opposed to lithium batteries, have a lower energy density and a faster rate of energy dissipation.
How can I figure out how many batteries my system needs?
The ability of the batteries to provide each household's energy demands must be considered when constructing a solar system with a storage system. And here is exactly where you should begin. However, a presumption must be established: the photovoltaic system cannot provide 100% of the yearly energy requirement since there are fewer opportunities to create electricity during the winter because there is less sun irradiation. It is possible to reach, on average, a stunning achievement of 75% independence.
It is necessary to start with usage when determining battery size. Each power bill includes the yearly kWh consumption. For instance, if a household consumes 3000 kWh annually, 30% of that energy is used immediately after production, with the storage system's batteries able to handle the other 70%.
A preliminary calculation shows that 900 kWh of the 3000 kW consumption per year are utilized immediately after production; the remaining 40% of 3000 kW, or 1200 kWh, must then be provided by the batteries (the difference between 70% and 30%).
This is not the only value to consider; we also need to take into consideration how many charge and discharge cycles the batteries must undergo annually. 320 rounds a year is the most precise estimate, while one round per day is a good indicator. The value of the battery model we fictitiously want is 3.75kWh, which is obtained by multiplying 1200kWh (the amount of energy we require from our batteries) by the 320 cycles each year.
The recommendation is to go beyond and purchase batteries that cover more kWh requirements because this is, of course, an approximated amount and there aren't batteries of every denomination.
What position should PV batteries be in?
The location of the batteries in the solar storage system is a crucial consideration. We're talking about frequently large and hefty items that need to be correctly linked to the system and set up in order to operate securely and as effectively as possible. The best installation is in a separate box, if feasible, or in the basement or garage, in any case in a covered and protected place with a big supporting surface on which to store the batteries. This is because, in addition to the problem of clutter, there is frequently also the issue of noise.