OptiMate 6 12V/24V GOLD series: 8-step 12V 6A / 24V 3A sealed battery saving charger & maintainer. The versatile battery charger for 12V or 24V lead-acid batteries, best for deep cycle batteries! Ideal for 12V and 24V deep cycle and starter (SLI) lead-acid batteries. Select the right charge voltage for your 12V and 24V lead-acid battery. Selection remains in memory even if AC power is lost. Fully automatic multi-step program brings the battery safely to full charge. Connect to the battery and OptiMate 6 12V-24V does the rest, no supervision required! AMPMATIC: Automatically adjusts current to match battery size and condition. Temperature compensation: Voltage is adjusted higher when colder, or lower when hotter. Safe to leave connected. Full electronic protection. Maintains battery at full charge and good health. Saves your ‘dead’ battery from as low as 0.5V. S.O.H.: Tests battery state of health. Voltage safety check: will not charge if battery voltage does not match selection. Requires user confirmation. Green Technology: 50% less energy, 50% lower cost, Power Factor Correction and Synchronous Rectification. IP54: Weatherproof. Rated for use down to -40°C / -40°F.