How to Tell if a 12V Battery Is Charged
Sometimes it can be hard to determine if a battery is fully charged. A fully charged 12V battery should show a volt reading between 12.2 and 12.6 volts. You can check the charge on a 12V battery by hooking it up to a digital multimeter and reading the volt measurement.
- Purchase a digital multimeter from you local auto parts store. Some stores may also allow you to rent a digital multimeter if you would rather not purchase one.
- Turn on the digital multimeter. Set the multimeter so that it reads "DC Volts." This will allow the digital multimeter to read the volt strength of the battery. This volt measurement number will be displayed on the multimeter screen.
- Attach the positive clip to the positive battery terminal and attach the negative clip to the negative battery terminal. The positive clip and terminal will be red and the negative clip and terminal will be black.
- Read the number on the multimeter screen. If the 12V battery is fully charged, the multimeter screen should display a number between 12.2 and 12.6 volts. If the multimeter reads a number any less than this, the battery is not fully charged or is not a good battery. Attempt to charge the battery with a battery charger and test it on the multimeter again. It may take several hours for the battery to charge. If the battery is still not reading between 12.2 and 12.6 volts, the battery may not be able to hold a charge and should be disposed of properly.