Battery Problem

[ElMatador]

Hi, I have suddenly started experiencing a problem with my battery. My car just won't start. It's not completely dead as the the lights inside and everything works but it won't start. I have to use jumper cables to jump start and then it starts immediately and I can drive for 2 or 3 hours but as soon as I turn it off it won't start again. I have even charged the battery with a car charger and the charger shows charged but still nothing ... What bothers me is that my car don't show any battery or warning lights. Is it the battery that needs replacing or can it be something else? I drive a 2011 E90 335i. Thank you in advance.

 

[Ratslaaf]

You might have a dead cell in the battery, or at least a poor internal connection. It'll only show up under high current demands. Best would be to try another battery in the car to be sure.

 

[MikeR]

Dumb quetion, have you cleaned the terminals.

 

[ChefDJ]

Get the battery tested at any battery replacement centre for dead cells, and take it from there.

 

[kilotango]

the volts could be pushing 12v correctly, but seems like the battery under load is failing.

a loose terminal could do something like this... but its probably just a battery that needs replacing.. :coolShake:

 

[Maljan]

Get the battery tested at any battery replacement centre for dead cells, and take it from there.

I have a suspicion that those tests are designed to fail any battery that gets attached to it. It is just a great big resistor. If crank the wheel on it any battery would eventually boil at least one cell. Call me a cynic if you want.

If it was my car I would hook up a voltmeter. With the car off, a charged battery should read 12V. With the engine running, there should be 13.8V on the battery if the alternator is working. If you don't have one, get a cheapie from any convenient hardware or parts store.