When choosing the best battery option for solar and storage in Commercial and Industrial solutions, there are a few important factors to consider. Let’s evaluate each in detail:
Energy capacity refers to the total amount of energy that a battery can store and is measured in ampere-hours or watt-hours (Wh). The design of the modern battery system is scalable. The size of the storage system can start from few kilowatt hours and can go up to hundreds of megawatt hours keeping a consistent design. While a battery with a high capacity and a low power rating would deliver a low amount of electricity for a long time, a battery with low capacity and a high-power rating would be able to bear the entire load, but only for a few hours.
Depth of Discharge (DoD)
The depth of discharge (DoD) of a battery refers to the amount of a battery’s capacity that has been used. It is denoted with a percentage value of the total capacity. Owing to the chemical composition of the battery, the life of the storage system heavily depends on the maximum DOD level the battery is discharged repeatedly. In simpler words, a higher Depth of Discharge means that more of battery’s capacity can be utilized by the consumer. Most battery manufacturers specify a maximum Depth of Discharge for optimal performance of batteries.
The round-trip efficiency of a battery depicts the amount of usable energy that is stored in the battery. It also represents the round-tip energy losses of the storage system. The efficiency of Lithium Iron phosphate battery is 95% compared to the lead-acid batteries which are 80%-85% efficient. Having a high efficiency battery bank can translate into fewer solar panels, less battery capacity or small backup generator depending on the system configuration.
Lifespan refers to the number of years a battery can be used effectively, and can vary depending on a number of factors. Solar applications generally require one charge-discharge cycle of the battery per calendar day. A lead Acid battery designed for solar applications can provide around 1000 cycles which can roughly last for 2.7 years While Lithium-ion batteries can provide 3000 – 10,000 cycles, depending on the manufacturer, and can last up to 10 – 30 years.
While all these factors depict the performance of the battery, for a complete picture, it is important to consider other factors as well, such as the C-rating, manufacturer reputation and warranty before you invest in a battery system.