Solar battery bank buying guide

Begin with daily watt-hours: load watts multiplied by hours of use. Add inverter and wiring losses, desired reserve days and the battery chemistry’s recommended depth of discharge. Convert to amp-hours only after choosing system voltage.

• Flooded lead-acid is established and serviceable but requires ventilation, watering and conservative discharge. AGM reduces maintenance but still needs lead-acid charge settings.
• LiFePO4 generally offers more usable capacity and cycle life with less weight, but depends on a quality BMS, compatible charger/controller and low-temperature protection.
• Series and parallel banks must use matched batteries, correct overcurrent protection, balanced connections and cables sized for fault current.