Quick Answer
Flooded Lead-Acid batteries are generally cheaper upfront at around $150-300 per kilowatt-hour (kWh), while Lithium Batteries cost around $300-600 per kWh, but offer longer lifetimes and higher efficiency.
Cost Breakdown
When comparing the cost of flooded lead-acid (FLA) and lithium batteries, it’s essential to consider the total cost of ownership. FLA batteries have a lower upfront cost, but they require more frequent replacements and maintenance, typically every 3-5 years. Lithium batteries, on the other hand, can last for 10-15 years or more, reducing the need for replacements and maintenance costs.
Efficiency and Lifespan Comparison
Lithium batteries have a higher round-trip efficiency, around 95%, compared to FLA batteries which have an efficiency of around 80-85%. This means that lithium batteries can recover and deliver more of the energy stored, resulting in a higher overall efficiency. Additionally, lithium batteries retain their capacity over time, while FLA batteries tend to degrade faster.
Real-World Example
Consider a 10 kWh off-grid solar system. With FLA batteries, you might need to replace the batteries every 5 years, at a cost of around $1,500 per replacement. This adds up to $3,000 over 10 years. In contrast, lithium batteries might last for 15 years or more, requiring only one replacement, saving you around $2,400 in replacement costs over the same period.
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