The criteria to take into account to choose your solar battery
The energy transition towards renewable sources is in full expansion and the use of solar batteries is increasingly common for storing energy produced by solar panels.☀️
However, there are many criteria to consider when choosing the solar battery best suited to your needs.
In this article, we will cover the main considerations to take into account when making the good choice for your solar system . From the storage capacity to the lifetime passing through the depth of the discharge , we tell you everything in our article!
Battery capacity
Capacity simply describes the capacity of the solar battery to store electrical energy . It is expressed in kWh .
Lithium batteries are characterized by a higher capacity at equal volume than all types of lead batteries due to their better energy density.
While a lead battery will have a density of around 35Wh/kg , Lithium battery is 6-8 times denser depending on the technology . The higher energy density of lithium battery means it can be installed in hard to reach places, as it can fit more capacity into less space, which is why it is used in electric vehicles. If you install these solar batteries yourself, you may face several difficulties related to the high weight of lead.
For a self-consumption system, it is common to choose a battery that will be cycled daily (the excess energy stored during the day is emptied at night). The generally recommended size is 1 to 2 kWh of battery capacity for each kWp of solar panels installed . If we take the example of a house in Chambéry with an annual consumption of around 7,000kWh, it is recommended to install 6kWp of panels (i.e. around 14 to 16 panels). The natural self-consumption rate of such a house will be around 35% without a battery and the addition of a 10kWh battery will increase it to 60 or even 65% .
Solar Battery Depth of Discharge
There depth of discharge (DoD) of a solar battery is the usable portion of its capacity. A recommended discharge depth of at least 40% allows for optimal battery usage.
Lead-acid batteries typically have a DoD of 50%. Lithium-ion and sodium-nickel-chloride solar batteries, on the other hand, have a DoD of 80%, which implies a higher usable capacity.
To learn more about the different types of solar batteries, we invite you to read our article .
Solar Battery Life and Warranty
When you decide on the solar battery to install in your system, its lifetime is the best indication of its ability to preserve its capacity.
A charge cycle is simply the return to charge after a discharge and is the primary measure of the battery life . Additionally, the number of cycles your solar battery will go through depends on how intensively it is used.
This attribute differs for the same type of solar battery: it is affected by the depth of discharge of the battery. A warranty is always a good sign of reliability for any brand or product, and this also applies to solar batteries. While lead-acid batteries are most often guaranteed for 2 years, those at lithium-ion are guaranteed for 10 years.⏱
The efficiency of the solar battery
The efficiency of a solar battery is the difference between the energy available and the amount of energy used to charge it . As with the battery's depth of discharge, the higher the efficiency of a battery, the better. Lithium-ion solar batteries are the most efficient (95%). This is because they have the highest conversion rate of solar energy to electrical energy. This means that you may need to install fewer solar panels and batteries, depending on your system configuration.
THE charging regime is another thing to pay attention to when choosing your solar battery, as it indicates how quickly it will recharge when power is available. It is expressed as a fraction of the capacity. Lead-acid, with slow charge rates of around 5 to 10 hours, can take up to three to five times longer than lithium-ion solar batteries to charge.
In summary: which battery for which solar application?
By keeping these parameters in mind, you can plan and install your solar system accurately. Depending on how you want to use your system (self-consumption, main power supply on an autonomous site or backup) , you can choose the type of solar battery that suits you best.
The lithium-ion type is recommended for self-consumption sites where intensive use is made with a complete cycle per day. Their robustness and performance make them technically much more suitable for such an application.
The batteries lead acid open and the lithium-ion batteries are ideal for a stand-alone system power supply that will be used regularly. If you are looking for a battery to use in your vacation home or somewhere you won't spend much time during the year, the type sealed lead acid is your best economical choice. It requires no maintenance and has a low self-discharge rate.
When choosing a battery for backup purposes only, you need to consider how often your grid will experience power outages to determine how often it will be used throughout the year. If it is used only infrequently, you will benefit more from a low-maintenance battery like a sealed lead-acid solar battery.
On Oscaro Power you will find different types of solar batteries . Do not hesitate to contact our customer service so that our experts can advise you on your installation.
