A battery is not designed to last forever. However, with
proper care, the battery will provide years of good service. If the battery
tests good but still fails to perform well, the following are some of
the more common causes:
| • | A vehicle accessory was left on overnight. |
| • | The driving speeds have been slow with frequent stops (stop-and-go
driving) with many electrical accessories in use, particularly heating or
air conditioning, headlights, wipers, heated rear window, heated seats
etc. |
| • | The electrical load has exceeded the generator output (particularly
with the addition of aftermarket equipment). |
| • | Existing conditions in the charging system, including the following
possibilities. |
| • | The battery has not been properly maintained, including a loose
battery hold down or missing battery insulator if used. |
| • | There are mechanical conditions in the electrical system, such
as a short or a pinched wire, attributing to power failure. Refer to
General Electrical Diagnosis
in Wiring Systems. |
Electrolyte Freezing
The freezing point of electrolyte depends on its specific gravity. A
fully charged battery will not freeze until the ambient temperature gets below
-54°C (-65°F). However, a battery with a low state of charge may
freeze at temperatures as high as -7°C (20°F). Since freezing
may ruin a battery, the battery should be protected against freezing
by keeping it properly charged. As long as the green eye is visible in
the hydrometer, the freezing point of the battery will be somewhere
below -32°C (-25°F).
Battery Protection During Vehicle Storage
Certain electronic devices on the vehicle maintain a small continuous
current drain (parasitic load) on the battery. A battery that is not used
for an extended period of time will discharge. Eventually permanent damage
will result. Discharged batteries will also freeze in cold weather. Refer
to
Battery Inspection/Test
.
In order to maintain the battery state of charge while storing the vehicle
for more than 30 days:
- Make sure that the green dot is visible in the built-in hydrometer.
Caution: Refer to Battery Disconnect Caution in the Preface section.
- Disconnect
the battery negative cable to protect the battery from discharge by parasitic
current drains.
When the battery cannot be disconnected:
- Maintain a high state of charge.
- Establish a regular schedule for recharging the battery every
20-45 days.
- When a battery is found without a green dot visible in the hydrometer
refer to
Battery Inspection/Test
.
A battery that has remained in a discharged state for a long period
of time is difficult to recharge or may be permanently damaged.
