A battery is not designed to last forever. With proper care, however,
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 air conditioning,
headlights, wipers, heated rear window, cellular telephone, 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 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 ground 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.
A battery that has remained in a discharged state for a long period
of time is difficult to recharge or may be permanently damaged.
