If you ever had a rechargeable battery that quit charging after being neglected for a while, or depleted the battery to the point that it won’t change anymore, don’t throw it away! Instead of replacing the battery, sometimes you can trick the charger to think it is still fine. Rechargeable power tools and other items sometimes indicate a faulty battery if the voltage is too low, but this hack will trick the circuitry into believing it is not faulty after all. Before attempting this on any of your batteries, please research the positive and negative points to attach your wires! Also, rechargeable battery packs aren’t always 4.5v, so add or delete cells as needed to accommodate your application.