Solar battery options are important when designing an off grid system.

Solar Battery Types

• Lead Acid Batteries: Originally invented in 1859, lead based batteries are still the most commonly used battery type in off grid systems. This is because the technology is well understood, dependable and relatively cheap compared to other storage options.  Common practice calls for a max 50% depth of discharge to preserve battery life. Lead Acid batteries come in two types:
  • Sealed Lead Acid: is a type of lead acid battery that seals in liquids. Sealed batteries benefit from being relatively maintenance-free.
    • Valve Regulated Lead Acid (VRLA): VRLA batteries utilize a gel like compound that contains the electrolyte. These batteries are able to combine oxygen and hydrogen, making them very low maintenance. VRLA batteries cost more than flooded batteries and their fellow sealed battery the AGM. This cost increase is warranted by extended life, capacity options, and performance life.
    • Absorbent Glass Mat: AGM batteries store their electrolyte in a fiberglass sheet, making it spill free and low maintenance. AGM’s are only an option in smaller battery bank sizes and suffer from linear performance degradation and shorter lifespan when compared to VRLA.
  • Flooded Lead Acid: Flooded batteries are still used in the industry but are only recommended for experienced users. Flooded batteries present a safety hazard and require regular maintenance due to oxygen and hydrogen gas being released during overcharging. Customers experienced with flooded batteries will sometimes request them due to their lower price and high energy capacities.
• Nickel Batteries: Nickel-Cadmium (NiCd) and Nickel-Metal-Hydride batteries are more common in smaller capacities. Because of this, they do not have many notable options for high capacity battery banks. NiCd is an older and proven technology that typically cost 3 to 4 times more than lead acid but is said to offer longer performance.
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  258 Ah Battery Bank

  Nickel Iron: Is separated from the proven NiCd and NiMH batteries due to its scarce use in the industry. The chemistry of the battery has a rich and interesting history but the nickel-iron batteries on the market today are not the same. We have not used the new nickel Iron batteries and advise consumers to be cautious when considering them.

• Lithium-Ion: is a term given to new battery technologies that utilize lithium as part of the batteries cathode (positive electrode). Lithium-ion batteries have taken the small electronics market by storm and have begun entering the larger capacity hybrid automobile industry. They benefit from much higher capacity (energy density) than lead-acid and nickel options. However, they are SLOWLY becoming available in the renewable industry market and have a safety concern of thermal run-away.