Charger automatically switches to Float Mode when fully charged. Absolutely no danger of overheating or overcharging. Leave it connected for months at a time if necessary. Designed to charge AGM, sealed maintenance free, lead calcium and flooded batteries. Manufacturer recommends checking battery fluid monthly. 4-step charging (Initialization, bulk charge, absorption mode, float/maintenance). Spark Proof. Temperature compensated. Short circuit and reverse polarity protected. 10-year manufacturers warranty.