If the battery on the BMW 325i is discharged to the point that it can no longer generate sufficient power to start the car, you can use another car to jump-start the dead battery. Once the 325i is running, the alternator will recharge the battery. As long as the battery is not damaged, allowing the car to run for several minutes should be sufficient to recharge the battery.
Position the car you will use to jump-start the dead battery close enough to the BMW 325i to allow the jump leads to reach both batteries. Ensure that the two vehicles do not come in contact with each other.
Turn off the engine of the support vehicle.
Open both vehicles' bonnets.
Lay out the jump leads so the two clamps on each end of the jump leads are not touching.
Remove the cover of the BMW's auxiliary jump-starting terminal. The terminal is located on the passenger side of the car, near the firewall. The cover is marked with a "+."
Connect one positive jump lead clamp to the positive terminal on the support vehicle's battery.
Connect the other positive jump lead clamp to the BMW's auxiliary jump-starting terminal. If you cannot locate this terminal, attach the clamp to the positive terminal of the BMW's discharged battery.
Attach one negative clamp to a suitable ground point on the support vehicle. This can be any location that is connected to the vehicle's frame. Most vehicle's are equipped with a special jump lead ground attachment point. If you can't locate a suitable connection point, connect the negative clamp to the negative terminal of the support vehicle's battery.
Attach the other negative clamp to the grounding nut on the BMW. This is a special feature on the 325i. The nut is located close to the BMW's auxiliary jump-starting terminal and is attached to the car's body. If you can't locate this nut, attach the negative jump lead clamp directly to the negative terminal on the discharged battery.
Start the support vehicle and let it run for several minutes. Lightly press the accelerator to increase the engine idle speed. This will speed the charging process.
Start the BMW 325i. If the engine will still not start, wait several more minutes and try again.
Remove the jump leads from the two batteries in the reverse order of how you attached them.
Do not let the positive and negative clamps of the jump leads contact each other at any time during the jump-start procedure.