In an attempt to keep the lights on when the grid goes down, you have installed an off-grid solar system backed by batteries. However, now you want to use the best batteries for this purpose. Regular advancements in technology have made batteries cheaper and more efficient. Although still on the expensive side, batteries are environmentally friendly and run on a free energy source as compared to gasoline-powered generators.
All solar panels work on the same principle; they convert sunlight into DC power by using photovoltaic cells. The DC power generated is converted in AC by the solar inverter or stored in the battery and run home appliances. Depending on the type of solar panel, excess energy can either be sent to the main energy grid for others to use or stored in different batteries for use during non-activity hours.
If you wonder which batteries are best for storing solar power, then there is no one-size-fits-all answer. You can get batteries that best fit your budget and goals.
Below are some battery-related terms explained:
Capacity refers to the amount of energy your battery can hold. Like any other energy, the load capacity of the battery is measured in kilowatts. The greater the battery’s capacity, the more energy it will hold.
Power is referred to the amount of energy a battery can provide at a single time. This, too, is measured in KW (kilowatts). These two characters go hand in hand when it comes to storing extra energy and keeping your load running during non-activity hours.
A high-capacity battery can store a lot of energy, while a high-power battery can run an appliance that uses a lot of energy.
Depth of discharge is referred to the percentage of the battery’s capacity you use. For example, if the battery holds a 15 KWh charge and you use 12.5 KWs of it, you are using 83% of its capacity. This 83% is the battery’s depth of discharge.
Manufacturers recommend using a specific DoD of the battery. 100% capacity usage is never recommended as it significantly lowers the useful life of your battery.
Every charging and discharging cycle decreases the battery’s ability to hold charges. This is what we call battery lifetime, for which the battery is able to hold charges efficiently-.
Most batteries come with a warranty that specifies battery efficiency for a certain number of cycles or times. As with other parts of the solar system like panels, cells, and inverters, getting batteries from trusted manufacturers/suppliers that can honor these warranties is a safe option to go for.
Lead-acid batteries have been used for offgrid solar panels for decades now. There are different types of lead-acid batteries in the market, including flooded batteries, wet-gel batteries, absorbed glass mat batteries, etc. flooded batteries need to be refilled with water regularly to avoid evaporation of electrolyte components. While the absorbed glass batteries do not require this extended maintenance.
However, being the cheapest battery option, these batteries have a shorter life and lower DoD as compared to lithium batteries. Another caveat is that all types of lead-acid batteries need regular maintenance, use, and ventilation to perform correctly. You should prepare yourself to use the batteries regularly as they can release harmful gases when overcharged and not maintained regularly.
Lithium-ion batteries have become a popular option to store solar power and continuously improve and become more affordable. These batteries are smaller, sleeker, and safer options for solar energy backup but are still on the expensive side of the price scale.
Lithium-ion batteries have significantly longer battery life and offer better DoD (about 80%-90%) as compared to lead-acid batteries.
Although there are some security concerns related to fire, lithium batteries do not produce toxic gases like lead batteries. Moreover, their lightweight and smaller size make installations easier.
Saltwater Batteries
Sodium batteries that use salt to produce power are commonly known as saltwater batteries. They are the safest battery options with no toxic gas production and no threat of catching fire. Saltwater batteries can be drained without damaging the batteries (no DoD constraints).
Saltwater batteries are cheaper than lithium batteries but expensive than lead batteries. These are best for people with safety concerns.
Having the best solar storage battery is the only way to make maximum use of your off-grid solar panel investment. Storing the green energy for later use makes them environmentally friendly activity more fruitful. So, whether you are concerned about initial investment, safety, or battery life, choosing the best solar storage battery depends totally on your needs.
