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2015 Subaru Forester - Drains its battery

Since it was new our 2015 routinely drains the battery when it has not been driven in a few days. I took the car to the dealer about this problem when it was new and they didn’t diagnose the electrical drain, they just replaced the battery with another stock version.

I replaced the replacement battery with a high capacity version which has extended the number of days until drained to ~7. The car has to be left on a trickle charger or it won’t start in a few days. Has anyone else had a similar problem? Is there a solution?

You have put up with this for 5 years ? Why ?


Sure, fix the parasitic drain like the dealer should have done 5 years ago.

Or use a trickle charger.

Or install a battery disconnect.

Pick a solution that works best for you.

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You can try checking for a battery drain,

Do you have any aftermarket electronics installed?

As already mentioned, someone needs to measure for a parasitic draw. As an alternative, you could start pulling fuses each time the car is parked until you find the one that’s causing the problem, which would narrow down the suspects.

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You’re quite right, I shouldn’t have put up with it. Part of it was that the dealer was resistant to diagnosing the problem any further than replacing the battery. My replacement with the higher capacity battery masked the problem. Using the trickle charger made it tolerable. There are comments from other Subaru owners on the internet having a similar problem but no definitive solution.

Do you have a paper trail documenting when the problem first occurred i.e. during the warranty period? Maybe Subaru corporate will provide some assistance despite the expiration of the warranty. Keep in mind the old adage involving flies, honey, and vinegar.

I do have that, thanks. I need to take it back to the dealer to diagnose. Hopefully, after all this virus problem has settled.