charging problem

[e30wavee]

Hey rev my BMW 325i doesn't want to hold charge,I changed the battery changed the alternator clean all the grounds let the car run for about 10 minutes still seem to die I dont get nothing not even a click ?? What can cause this

[jlevie]

The first check should be to see what the battery voltage is. A fully charged battery will be at 12.7v and anything below 12.2v is a problem. The next check is to see if battery voltage is applied to the starter solenoid when the key is turned to start. If so check the voltage at the starter main lug and the voltage between the starter body and a frame ground when the key is turned to start. The starter main lug should have battery voltage and the voltage from the starter body to ground should be essentially zero. If there is no power at the starter solenoid or it is below battery voltage, work back to the ignition switch to find out why. If all of the voltage checks are okay, the starter is bad.

A check of the alternator is to measure system voltage while the engine is running. You should see ~13.5v at idle and it should rise to ~14v at 2500rpm.