Ok, a few months ago my original battery in my 97 850 finally started to go. It was getting hard to start on the cold mornings and I had to have it jumped off a few times. I replaced the battery and everything was fine for a few weeks. Then all the sudden it became hard to start again just like it did with the old battery.

These are the symptoms:

I can start the car fine every morning. Sometimes I will go out on my lunch break and it won't start. It seems like if I let it sit for 10-15 minutes I can come back and start it just fine. When I turn the ignition I hear a click that is it, but if I keep trying it seems like the click goes away. I can go around town to several different places just fine, but then all of the sudden at one it won't start, when it won't start I can get it jumped and it starts just fine.

Thanks for any help!

 

With the car running check the voltage output from the Alt to the battery. If it seems pretty low probe the wire just before the battery terminal and see how much more voltage there is.

 

Also check to make sure all connections are tight and the ground points are clean