Force mode: to activate low voltage “dead” lead acid battery or wake up “dead” LiFePO4 battery. Safe: connection spark free, reverse polarity, short circuit and internal overheat protection. Charges and maintains 3 batteries with different voltage and technologies at once. Adaptable charging algorithm for lead acid and lithium (LiFePO4). Auto detect lead acid or lithium technology. Easy to use: connect and forget. Battery size: up to 40Ah.