Dead battery in my '91 Fleetwood

[FleetwoodMac]

Hi. I'm new to this forum and would like some help. I have a new battery in my '91 Fleetwood which I don't use that often. After sitting for 2 weeks the new battery was drained. Any ideas what caused this?

[MAC]

This is what the GM Service Manual says:

The battery is not designed to last indefinitely; however, with proper care, it will provide many years of service. If the battery tests good but fails to perform satisfactorily for no apparent reason, the following are some factors that may point to the cause of the trouble:

1. Accessories left on overnight.

2. Slow average driving speeds for short periods.

3. The vehicle electrical load is more than the generator output, particularly with the addition of after-market equipment.

4. Conditions in the charging system such as electrical shorts, poor ground circuits, slipping drive belt, faulty generator or voltage regulator.

5. Battery abuse, including failure to keep the battery cable terminals clean and tight, or a loose battery retainer.

6. Mechanical conditions in the electrical system such as shorted or pinched wires.

7. Extended storage of vehicles.

8. Batteries not having sufficient charge when put into a vehicle.

9. Extended cranking due to a vehicle problem.

10. Incorrect interpretation of the hydrometer.

In addition, a certain amount of self-discharge is always occurring as a result of internal chemical reactions even when the battery is not connected. This explains why the number of discharged batteries may increase in very hot weather. The Delco Freedom battery has a much lower rate of self-discharge than conventional batteries, however, self-discharge at 100º F ambient can be as high as 7mA.