Unexplained Flat Battery

[BD314]

My Superb is two years old with 25k on the clock and always starts reliably and covers around 100 miles daily.  Recently did a 50 mile journey (daytime), parked the car, only to find that it wouldn't start 5 hrs later when I returned.  Just enough juice to unlock the door,  but not engage the starter or do the lights self check thing.  

 

Nothing was left on (interior lights etc).  I'm at a loss to understand how and why the battery could be drained so quickly.  The only difference is that it was parked on a bit of a slope, but can't see how that could change anything.

 

Any thoughts welcome.

Edited 23 September, 2015 by BD314

[psycholist]

A few people on here have had similar experiences. Often it's some part of the car electronics that hasn't shut down properly and continues to drain power (The Columbus radio is a common culprit). Get your dealer to monitor the current drawn from the battery while the car is off to check for this fault. If the current is high then pull the radio fuse and see if it drops. The problem is that it's usually intermittent, so it's not guaranteed to happen every time. The car electronics are supposed to be smart enough to shut off power to everything that's not critical to starting the engine if the battery charge is too low.

[bw10030]

Or you may have a dodgy battery. Modern batteries do catastrophically fail without warning - i.e. one minute they are fine, then next minute dead. The old days of 'slow cranking' or 'dim lights' are a thing of the past.

 

However 5 hours from (nominally) fully charged (after a drive) to effectively flat is more than just a little drain - can the Columbus system really take that amount of current? It may be that the battery didn't charge after the last start (alternator not working) and you effectively drove on 'battery power' only, prgressively flattening it? There should be a warning (red ignition light) if this happens though?

 

It's unlikely to be a dead battery at 2 years old (though you could be unlucky) or an alternator - and easy enough to test, when you are getting the dealer to look at current drain, also get him to test the health of the battery and its charging.

 

There's not much else it can be!

[lali]

my battery died and it was the alternator

[Danny 57]

Known battery fault as said mine had it. Battery replace and up date on system under warranty.

[revneth]

Had a similar problem with my Superb 2 at 18 months, rang Skoda Assist, they send the AA Battery man who tested it and said he couldn't find anything wrong as it was charging properly, thought something hadn't switched itself off, recharged the battery and told me to visit my dealer. Dealer had the car for 24 hrs, tested it, couldn't find anything wrong. Went totally flat again. This time after taking some Briskoda advice, I rang Skoda Assist and asked them to send one of their technicians, not an AA Battery man. He had some high-tech equipment, tested the battery and found it had a faulty cell, replaced it under warranty and it's been fine ever since. 

[lichfielddriver]

you dont need any hitech kit to test a battery, just a drop tester, one of those and a voltmeter to check the actual alternator performance (dont think the warning lights are enough) is all you need

 

sometimes the old ways are the best

 

 

[peterposh]

I had a varta battery die on a 6 month old vehicle, changed under guarantee , 1 cell had packed up

Edited 25 September, 2015 by peterposh