Lesson 1/Learning Event 1
Most military vehicles use a battery indicator instead of an ammeter. The indicator is really a
voltmeter that has a color-coded scale instead of a numbered scale. The different pointer portions
can indicate the condition of the batteries and whether or not the generator has been doing its job.
The batteries themselves are also good indicators of what the charging system is doing. If the
batteries must be charged very often by an outside source of current (a battery charger), the output
of the vehicle generator is probably too low. On the other hand, if the water in the battery
electrolyte is constantly boiling away, the generator voltage output is probably too high. When the
generator output is too low, always check the drive (fan) belts. Slipping belts will cause a low
The drive belts are not the only things in the charging system you should inspect. Look for
missing or loose generator mounting bolts and loose or damaged cables and connections. Correct
any faults noted before testing the charging system.