Battery issue

[rossa123]

During November the battery in my 986 Boxster S (2004) failed so I bought a replacement from porsche -
today after not having used the car for just 3 days the alarm started and the car wouldn't start - also the windows dropped a couple of inches.
I now have it on charge so hopefully all will reset and be ok -

My question is why would the battery be flat after only 3 days of not being used-I can leave my other cars for 3 weeks !!

thanks for any help.

[mikefocke]

The Boxster should be good for around 2 weeks if you didn't leave something on when you parked it. Did you measure the battery voltage before you put it on charge?

[rossa123]

I didn't measure the voltage - oops !
The car started fine this morning and I took the long way to work to give it a run , and the weather is nice -

The alternator was changed in March 2014 and the battery in Nov so hopefully it was a one off that caused the problem - I have checked the earth strap and that is well secured with no corrosion.

[wulfy66]

Couple of other possibilities - check carpet under passenger seat for any signs of dampness as this is where the ECU lives and will cause these kind of problems if it gets wet. Also, a failing ignition switch will also cause these gremlins and very common to fail on the 986