Check the listing for details. Top Post Battery Disconnect Switch Battery Disconnect Switch 3rd Gen Battery Kil. Condition: New, Made in United States. Listed at 7.95 USD. A standard battery disconnect switch provides a physical barrier that prevents power leakage, which is a common cause of battery corrosion and premature failure. Power leakage is a silent killer of vehicle batteries, often occurring when parasitic drains from alarm systems, lights, or accessories keep the battery weak even when the engine is off.