Flooded Lead Acid Batteries
Lead acid batteries are the most common deep cycle battery type. Lead acid batteries have been around a long time, which means they're well understood and have seen efficiency improvements over the years, though efficiency does drop gradually as they age.
Of all the energy storage media available, lead acid batteries offer the most bang for the buck (amp-hour capacity per dollar spent) by a wide margin. As a result, they are extremely common and all the renewable energy equipment on the market is designed to work within their typical voltage range. And they're 100% recyclable.
Our lead acid batteries are wet cell batteries (also called flooded). They need regular use, maintenance, and ventilation to thrive, so they are a much better choice for full-time off-grid homesteads than for occasional or emergency backup power. Lead acid batteries must not be allowed to freeze.
Flooded Lead Acid Batteries from Real Goods