Consumers should stop using these battery chargers immediately, and take them to a DEWALT or Black & Decker service center for a free replacement. We strive to provide the best quality battery chargers & testers at the best price. alone, more energy efficient battery chargers have the potential to save Americans more than 1 billion kilowatt hours (kWh) of energy per year, saving Americans more than $100 million annually while preventing the release of more than one million tons of greenhouse gas emissions — equivalent to the emissions of 150,000 cars. On average, ENERGY STAR qualified battery chargers will use 35% less energy than conventional models. Conventional automotive battery chargers — even when not actively charging a product — can draw as much as 5 to 20 times more energy than is actually stored in the battery.