What's causing my Ford Kuga's flat battery?

I have a 2012 Ford Kuga diesel. Recently, the battery has started to go flat every 10-14 days if its stood on the driveway or only used a couple of times a week for short journeys. It has had the Bluetooth software upgrade and the dealer says there is no drain on the battery, which is also fine. Any idea what could be causing this? Should I buy a new heavy duty battery?

Asked on 13 December 2016 by Jonathan Binnington

Answered by Honest John
This has been a problem with some Fords from Fiestas up. But a diesel used for short runs from cold beats its battery up very effectively because it takes out more than it puts in. Go on a 100 mile run in your Kuga and you may find you have put enough back into the battery for it to be okay, or it may have lost its capacity to hold a full charge of 13.5 volts.
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