CHarging Problems

Last week my alternator(or so I thought) went out on my 97 Windstar (3.0 L) Replaced the alternator and, since it is winter, and battery. Drove around for a day and spaarently sucked the alll the juice out of this brand new battery. All wiring is good. What else should I try? Obviously something is preventing a known good alternator from charging a known good battery.

I would suggest you obtain a voltmeter for some simple inspections of the system. I prefer the analog (with the indicator "needle") voltmeter, instead of the digital voltmeter, for most auto work.

With the engine running, you should have 14 volts across the battery posts. Compare to another car ... to make sure you've got the right voltage. Anything short of the 14 volts should make you suspicious of the alternator... or the cables and connections. A skilled person, using a voltmeter, can quickly isolate a cable or connection that needs to be serviced (cleaned, lubricated, re-fastened).... or other elect problem in the alternator-battery loop.

If you have ample voltage (14 volts) while the engine is running, that only leaves some "leak", that is draining the battery, to be your problem. This can be more difficult to pin-point. The battery may have its own internal leak...ie, "a bad battery". Or the leak can be external ... somewhere else in the car's electrics. If by disconnecting the battery, the battery stays charged overnight (13 volts or so next morning) ... you can be pretty sure the battery is OK and start looking for some electrical load that is not being turned off ...or some "short" of some kind.

Happy hunting!