battery non-charge problem

[19_again]

Easy answer to a dumb question. What would cause my battery to hold a charge through several weeks in the garage and a few very short 5-10 minutes test drives, but when I drive for an extended period say 25 minutes plus, the battery will barely turn the engine over and I need to jump it? Seems as if it's discharging when driving.
Mike

 

[Steve_S]

I would suspect a number of things. First, it sounds like a bad battery. If you charge it fully, and the car only runs for 30 minutes or less before the battery dies, then you have bad cells.

Beyond that, I would suspect the charging system, namely the generator / alternator. Also the control box.

Put a meter on the battery terminals and raise the engine RPM. You should see a charge of around 14 volts if memory serves.

 

[Kimberly]

Have you used a meter to check the voltage going to the battery after the car is started? Sounds like the alternator is not working or you have poor connections in the charging system.

 

[19_again]

Well so far I've gone for the easy solution of replacing the 5 year old walmart battery. When the thunderstorms pass, or in the morning we'll take 19 again out out for another ride. This time we'll ring our jump starter just in case. My gut feeling is bad battery. Latest update in the am.