Car Doctor Q&A: My 2016 Outback Battery Dies In a Few Days

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If you’re driving a late Subaru Outback, you may be plagued with battery issues if you park your car for more than a day or so. John Paul looks into solutions.

Q. I have a 2016 Subaru Outback with all the latest safety features and I love the car. It fits my needs as an artist and musician and handles poor weather with ease. But here is my problem: when I leave the car for more than a few days the battery goes dead. The first time I just assumed it was me leaving something on, but then it happened again.

I have had the car at the dealer twice now and they tell me the battery and the car itself is fine. One of the times the dealer representative told me that modern cars with all of their sophisticated electronics are not designed to be parked for any more than a few days.

I love the car but this is crazy. What is wrong with my car?

A. For the past year or so I have been hearing from Subaru owners from Alaska to Florida with similar issues. Typically the car is parked at an airport, long-term parking or even in the owner’s driveway for a few days to two weeks and then the car won’t start.

The idea that “modern” cars are not designed to sit idle for a week and just an excuse for not having an answer to what is actually wrong. My calculation of what is considered normal parasitic drain (50-75mA) on a Subaru battery should allow the car to start after three weeks parked without any issues.

I suspect there is a component in the car that is not shutting down properly. This could include the evaporative emissions pump, a power seat motor or some other component that is supplied with power when the key is off.

Until Subaru comes up with an answer I would look for a replacement battery with a higher reserve capacity. This won’t fix the problem but it could mask the symptom. You could also add a solar battery maintainer. These devices won’t charge a dead battery but could keep the battery in your car from completely discharging.

Two other areas that may be causing you problems: if the car is “keyless”, keep the fob a good distance from the car. The fob uses a proximity sensor and if the key is nearby the electronics may not completely shut down.

The second issue is that I have seen some drivers push the ignition button to shut off the car and actually leave the car in accessory mode. Before exiting the car take a quick look to make sure everything shuts down.

(Ed. Note: Our friends at CarComplaints.com have 10 registered complaints about battery issues in the 2015 Subaru Outback and another two for the 2016.

Reading into those complaints, it appears that the battery capacity of the stock battery in the Outback was the culprit.

Doing a little research, we found that the stock battery in a 2016 Outback with a 2.5-liter engine has a dismal 365 cold cranking amps (CCA). In a colder climate, that may just not be enough to reliably start the car when it’s left for a few days.

You can find a Group 25 battery — the correct dimensional size to fit in the battery tray — pretty easily at any auto parts store with between 550 and 625 CCA.)

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John Paul

John Paul