Makita batteries are rechargeable batteries used to operate various types of power tools. Each battery contains multiple cells wired together. Makita makes lithium and nickel batteries that produce various voltages, depending on the device they are designed to operate. For example, a Makita 18-volt battery may contain five lithium cells or 15 nickel cells. You'll find that after a while your battery doesn't operate your device for as long as it did previously. The best way to test your Makita battery, to ascertain its condition, is to use a multimeter.
Remove the Makita battery from the device it operates. Charge your battery in the battery charger until full.
Remove your Makita battery from the battery charger, once full. Don't insert it in the device it operates.
Look for the terminal connections on your Makita battery so you can identify the polarities. One is labeled "+" and the other "-".
Check the battery label to determine the voltage. It's clearly labeled so make a note of it on a sheet of paper.
Turn on your multimeter. To measure voltage, press the appropriate button, or turn the dial. Set it so it can measure up to about 25 percent more than the voltage on the battery label using the refine button or dial. For example, if your Makita battery produces 18 volts, set the maximum voltage on the meter to about 25 volts.
Place the sensor attached to the red wire from the meter onto the "+" terminal of the battery and the sensor attached to the black wire onto the "-" terminal of the battery.
Read the meter measurement. It reads the same as the voltage you noted earlier because your battery is fully charged. Turn off the meter and remove the sensors from the battery terminal.
Leave your battery for 12 to 24 hours. Don't insert it into the device it operates, or use the battery.
Turn on the meter and set it to measure voltage for the same range as before. Place the sensors on the terminals as before.
Read the meter measurement. It is the same or very similar to your previous reading if your Makita battery is in good condition; a difference of up to 1 volt is acceptable. If the voltage drop is between 1 and 3 volts, your battery is self-discharging and you may need to consider a replacement shortly. If the voltage has dropped by more than 3 volts, your battery needs immediate replacement.