sooby

Car draining battery - mechanic or auto sparky?

Recommended Posts

Howdy team Clubsub,

 

Last weekend our BP5 Legacy developed a dead flat battery, no big deal it was less than a year old and under warranty so was given brand new replacement from auto store Wednesday, started car and ran for less than minute and confirmed all good.  Had not used car since, then today went to start and AGAIN dead flat!

 

When I mean dead flat: the starter motor doesn't even click on turning the key, no lights on dash etc, our jumpstarter pack does nothing and C-Tek battery charger won't charge or even register as connected to a battery - it times out and switches off!

 

Now the odds of having two faulty batteries are slim, even more so with one less than a week old, so something in the car is draining the battery when the car is sitting idle.  Nothing obvious, no doors ajar, no aftermarket electrics anywhere in car

 

Not a typical lockdown flat battery either: car was driven roughly every 4 days to deliver/collect supplies for a distance of about 10kms and up to 80kph for some of it, would have thought that's enough to keep battery operational. 

 

Auto store said I can take it in for them to charge up Monday.  Once battery is running, do you think I should take car to a mechanic or auto sparky?  I'm thinking its more likely an electrical gremlin, so unlikely a part for mechanic to swap out.

 

Even better can anyone suggest what the problem may be?

 

Appreciate any advice and thanks in advance!

Share this post


Link to post
Share on other sites

Firstly check the park light switch on top of the steering column is switched off. It’s is very easy to accidentally turn this switch on and is by far the most common cause of a battery drain in a Subaru.

 

Definitely take it to an auto sparky, it is a 5 min check with a multimeter to work out if the draw is within a normal range and the alternator is charging properly. The battery will need to be fully charged first.

 

If it does have a draw it can be slightly more time consuming to find the cause but luckily for you it is a subaru not a euro so more than likely the draw would be related to an aftermarket accessory rather than factory wiring which makes it much easier to find.

 

Hope that helps, I deal with this kind of thing a lot at work.

Share this post


Link to post
Share on other sites
Posted (edited)

Sounds like a dead alternator to me... a mechanic will be able to diagnose and fix.

Edited by Loren

Share this post


Link to post
Share on other sites

So after hooking up the recharged battery, worked out the cause of the drain - boot light switch was left in 'on' position 🤦‍♂️

  • Like 2
  • Thanks 1

Share this post


Link to post
Share on other sites

One thing I love about swapping out all those funny little interior lights for LEDs... you could leave them on for a week and your battery probably wouldn't notice.

  • Like 3

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.