The NOCO GEN4 on-board battery charger uses an eight-step process to charge and maintain your battery. First, it checks your battery's voltage to make sure that the connections is good and that the battery is in stable condition before beginning the charge process. Second, it begins a bulk-charging process with a gentle (soft) charge. The process then continues and returns 80-percent of the battery's capacity. Next, it switches to a constant current charge rate to bring your battery close to a 90-percent charge, and then charges low current levels until the battery has reached 95-percent of its capacity. From there, the charger initiates a top-off charge to bring the battery to 100-percent. Finally, the GEN4 shuts off but constantly monitors your battery by providing a gentle charge every 24 hours for maximum battery life. The NOCO GEN4 on-board battery charger is backed by a three-year limited warranty. Keep your vehicle batteries charged and maintained with ease using the NOCO GEN4. This two-bank, 20-amp, fully automatic charger is designed to be used with batteries from 25Ah to 230Ah, such as those found in boats, golf carts, UTVs, ATVs, tractors, or generators. The GEN4 uses a thorough eight-step process to charge and maintain your battery and features a switch-mode design, resulting in a charger that's small and lightweight.