Open Circuit Voltage, Measuring

Open-Circuit Voltage, Measuring


CAUTION!
- Battery plugs must always be securely threaded when charging, measuring voltage and performing load measurements.
- Be sure to observe the following notes, or else a proper measurement cannot be guaranteed.


Special tools and equipment
- V.A.G 1715 multimeter or
- V.A.G 1362 mini-tester or
- Multimeter (Fluke 83 or equivalent)


NOTE:
- If the open-circuit voltage is being measured on a battery installed in a vehicle, it is imperative to disconnect the ground strap.
- The vehicle may not be driven or started with the battery to be tested for at least 2 hours before the measurement is taken.
- Power-consuming devices may not be connected to the battery for at least 2 hours before the measurement is taken.
- Loads may not be applied to the battery for at least 2 hours before the measurement is taken.


To measure the battery voltage without load, follow this procedure:
- With the battery installed and the ignition turned off, use a testing instrument to measure the voltage between the terminals.
- If the meter indicates 12.5 volts or more, the battery is in good condition.
- The battery's open-circuit voltage should never fall below 12.5 Volts, and if it does the battery should be recharged immediately. Battery, Charging