The Bosch GXS18 V-02N24 18 voltCore18 volt Starter Kit two Core18 volt batteries (and fast charger) gets users started with unleashed power and productivity. The Core18 volt 6.3 Ah battery is the best-built battery on the planet, while the BC1880 18 volt fast charger recharges the battery in less than an hour. Each Core18 volt employs next-gen Li-ion technology, producing 80% more power than previous-generation cells. Core18 volt s performance is comparable to competitor batteries that are up to 35% larger. CoolPack 2.0 technology provides up to 135% more battery life than batteries that don't have CoolPack. The BC1880 18 V fast charger can charge a spent Core 18 volt to 80% in 41 minutes and to 100% in 55 minutes. The charger has a dual-mode charge the first 80% is very fast, while the remaining 20% is in regular mode.