Bring out the voltmeter again to check if your battery is fully charged. If you find anything lower than that, charge the battery again for 12 hours. Units with a voltage below 10V are not eligible for reconditioning. A lithium-ion battery is considered irreversibly dead when its voltage drops below a certain threshold, typically around 2.5 volts per cell. At this point, the battery may not be able to be recharged using a standard charger, and may need to be replaced. Another method is to use a...