Why is it that when I leave my door open for more than 5 min's the battery won't be strong enough to crank the engine over. The battery is about 6 mths old. I checked my alt, it's puttin out about 14.4 Volts. The battery is reading about 12.7 volts. Is it my starter is going??? I can't really imagine that making a difference but, why else would this be happening. I don't believe there is a open circut drainning the battery because it can sit for days and start with no problem, but leave the door open or the radio on for 5 min's and your screwed. WTF????? Please Help!!!

 

It could be that your battery has very little charge in it. If your alternator is really weak it'll maintain the charge in the battery while the car is running but it won't actually charge the battery to the maximum capacity. Try hooking your car up with jumper cables to a second car. Let the second car run for a long time in order to fully recharge your battery. Unhook everything and see if this has helped the problem. Remember, if you're working on the car for a long time with any of the car doors open, you should pull the fuse labeled "Courtesy". It's a 15amp fuse that will kill the dome light/map lights, so you don't have to worry about killing the car battery.

 

Yea, but the battery should be lasting longer than 5 min's. The Alt read 14.4 on the Volt meter. Is that too low??

 

are the terminals tighened? loose will cause you tol lose power very quickly or not even work at all

 

...or you got a battery that has a problem and no reserve power.

 

If the connectors are tight and clean as mentioned above, it's possible you got a bad battery. Try putting it on a charger for a full charge and then take it somewhere that can do a load test on it.