Battery drain
 

Hello everyone,
I am a new Mustang owner. I bought a 2008 mustang convertible with 38,000 km.
The previous owner had installed an electronic rust inhibitor. The battery continues to completely go flat. I replaced the battery and it lasted about 4-5 weeks before it too, went dead.
As soon as I would attach the booster cables, on the old battery and new, it starts. It doesn’t hesitate.
I have disconnected the electronic rust inhibitor, thinking this could be drawing all the power. It went dead again after doing so.
I was hoping someone might have some insight as to where I should start looking.
many help is much appreciated.
taylor

Hello Taylor,

I'd check battery connections first. Clean and tight? You may have been boosting off the boosting battery only. I'd check that your alternator (charging system) is good. You haven't mentioned how much start/drive you have been doing. I'd check for parasitical draw when vehicle is parked, engine off. There is likely to be some small amount of usage when parked, engine off. To measure the amount of draw takes a visit to YouTube and a good multimeter. Don't go to a shop yet! You can do it!

Curt

Thank You very much Curt. That certainly gives me an idea where to start. I have watched several YouTube videos about parasitic drain. I will keep you posted.
thanks again.

Hey there!
Do you have a battery/check charging lights on while running?
Similar issue in my 2005 gt 31km on it.
Pretty common and the case for me was that leaves built under the wiper cowl and blocked the water drain.
This unfortunately causes water to leak into the passenger side interior kick panel where the SJB (smart junction box) is. This will cause the draw on the battery. I got lucky and saw no damage after removal (super easy to remove). Let mine dry in the house for a few weeks while car was still in storage. Now zero issues.
Hope this is helpful :)