Flooded Lead-Acid Batteries (FLA) VS Sealed Lead- Acid Batteries (SLA) Before telling you what three batteries are best for alternative energy system’s battery banks, it should be made clear why flooded lead-acid batteries (FLA’s) are better for renewable energy than sealed lead-acid batteries (SLA’s). One of the reasons that some people favour SLA’s is because they require little maintenance. Unlike FLA’s that need to be checked regularly for water level, SLA’s that are used properly can be left alone. However, sealed lead-acid batteries have two big flaws: they are sensitive and wear out quickly. So if you’re planning on using your solar panel or wind power system every day, this will eventually pose a problem. So, here are the categories of flooded lead-acid batteries that are best for an off- the-grid power system: View our Free Presentation to learn how to bring old batteries back to life again