Smaller than most smartphones, the NOCO Genius2 2A Battery Charger will charge 6V or 12V automotive, marine, and deep-cycle batteries, even batteries so dead they register zero volts. Simply plug in to an AC outlet, attach the clamps or terminal rings to any flooded, gel, AGM, maintenance-free, or lithium-ion battery, and press the button. The Genius2 will check the temperature and tailor the current to eliminate overcharging in hot climates and under-charging in cold climates. Normal charging works on batteries depleted as low as one volt, but Force Mode allows you to manually begin recharging batteries down to zero. Built-in diagnostics check for overcharge, shorts/damage, and reversed polarity. Finally, the Genius2 can detect sulfation or acid stratification that impair the battery's performance and repair the damage. The battery terminal clamps have a compact, needle-nose design for ease of use in crowded engine compartments. Terminal rings are built into the clamps and easily detached for a semi-permanent connection to the battery.