Metabo 627046000 ASC55 12V-36V Air-Cooled Lithium-Ion Charger with an Indicator battery pack is charged with 2.5 amperes with constant monitoring of voltage flow; temperature flow and maximum temperature. The charger ends the charging process immediately after full charging. Thus; there is no overcharging and the life of the battery pack increases. Charger switches to compensation charge: to conserve capacity; the battery pack is charged for 1 second every 45 seconds with 2.5 amperes. It has an "AIR COOLED" function based on air-cooling the battery pack during the charging process. The battery packs are gently cooled down to the required charging temperature; and then constantly maintained at optimum temperature during the charging process. This principle allows a higher tool life of the battery packs and up to 30% shorter total charging time to be achieved.