Lead acid batteries
Lead acid batteries are generally installed indoors because they have a preferred charging and discharging temperate range of 50°F – 80°F. While you can operate lead acid batteries outside of this temperature range, it will reduce the system’s lifespan and efficiency.
Lead acid batteries are also less energy dense than lithium ion systems. This means they will take up more space per installed kW or kWh unit. A single lead acid battery takes up about as much space as a shoebox. Multiple batteries are strung together to make a system large enough to power multiple loads in your home. Lead acid batteries must also be connected to a separate inverter, which must be wall-mounted.
Lithium ion batteries have a much wider preferred temperature operating range, typically between 32°F – 100°F. Additionally, lithium ion systems are more energy dense than lead acid batteries and are typically contained in one singular unit. Depending on the manufacturer, Li-ion batteries may or may not contain an integrated inverter. This further reduces the space required for these types of systems.
With lithium ion’s wider temperature range and smaller footprint, some manufacturers have designed systems that can be installed outdoors, typically mounted on the side of your home near your electric meter or solar connection. If you live in a climate with extreme seasonal temperature swings, you may want to install the battery indoors to maximize operating efficiency and battery life.