B9 - key fob/ignition/starting problem?

[Duane...]

Thanks all.

I disconnected the battery and measured the voltage, 12.53v. Connected the battery, 0v. Checked a few times, always 0v. Disconnected battery 11.73v, then tried again, 11.32v, increasing very slowly.

Doesn't sounds great for the battery right?

[Tomcat3]

At less than 12.00v the battery is nearly flat. How old is the battery is it the original one?

[Duane...]

Don't know I'm afraid, I only got the car in Feb and it's the one it came with.

[Sol]

0v when connected is a bad sign, the battery must be so weak that even the current the ECU draws is pulling the voltage to zero. You probably have bad sulphate deposits in the cells. They've grown enough to bridge enough cell area to lower the current available to a very low level.

[Duane...]

Thanks. I'm happy to replace the battery. Chance of alternator being faulty too?

[Sol]

That can only be known by testing. If you have a meter, you need to check the battery voltage once running, should be 14.4V approx. across the battery when the engine is running and especially when loads are on, like lights etc. much higher or lower indicates a faulty regulator in the alternator.

An over-charging alternator can buckle the battery plates inside too - need to check that.