Are you the original owner?

ANY type of aftermarket electronics installed on the car (stereo, bluetooth/apple/android adapters, auxiliary lights, LED swap for incandescent blubs, etc)?

My 2018 original OEM battery lasted me 6.5 years, I just replaced it last summer for the first time.

 

My 2018 original OEM battery lasted me 6.5 years, I just replaced it last summer for the first time.

Same (Panasonic battery) and same here. I have a dash cam, but that is plugged into the center console 12V power port and is shut down when the car is in "off" mode. No added-on vampire devices.

 

I am the original owner. The only added item was front and rear cameras installed by best buy. I have tested the settings on the cameras and verified that they are completely turning off as soon as the car is turned off, so they should not still be drawing power.

 

I don’t have all the details but a faulty DCM has commonly been traced to overnight dead batteries in some of your model year range. Subaru is well aware of the issue. There’s been a huge amount of media exposure. It can take a dealer tech a while before it gets figured out though. Short term, the fuse can be pulled. The DCM can be removed or replaced with a new non-faulty version.

It could be something else but this one sounds very familiar. It otherwise shouldn’t take Nicola Tesla to find where bleeding amps are going.

 

It could be the telematic module. It is a known issue to Subaru who recognizes the problem. They extended the warranty but refused to do anything for my family member's MY18. It killed their new AGM battery in a 1.5hr ferry ride as an example. Good luck with Subaru and warranty(always denied, refused , obfuscated).

 

As an added note, the service writer told me they are having supply issues if you can get them to replace it. If it is the issue, you might consider getting on the list for replacement earlier. Toyota has been having problems with their version of the telematic module as well(karma, for collecting data on their customers).

 

Maybe the DCM is still looking for a 3G cell phone frequency. There is a TSB for that.
Recently I viewed a YouTube video and the guy explained that in addition to doing a parasitic draw test you should check the relays. If a relay contact sticks closed the device it feeds will get 12VDC all the time. You could remove each relay and check for continuity for what should be the normally open contact. Use an ohm meter and refer to the schematic on the relay. You may be able to 'feel' the relay 'can' and see if it is warm. A laser temperature sensor may work. You could just remove all of the relays and turn them up side down in their correct position. Then see if the battery is no longer being drained. Then you will have to determine the bad relay. There may be more than one panel with relays. I think the relays have a plastic 'can' and probably can not be taken apart.
Also, check for trunk lights and glove box lights that may be ON.
Keep a battery charger connected when you are not driving. I do that on my new Wilderness and there isn't anything wrong. The computers just discharge the battery and the battery never gets fully charged by the alternator. The alternator could have a diode/rectifier that is acting like a resistor. Not sure how to test the alternator, but somebody does.
Do this YouTube search: "youtube video test the relays" and find a video that works for you.

 

Your Crosstrek came with Starlink activated? As mentioned above that's the likely (common) culprit. A dealer should be able to figure that out given the prevalence. It's easy to check. I have a 2018 Ltd.
Do a search on this site for DCM Telematics parasitic draw for more background.

 

@Crosstx2018

Another reason why I do not care for the fuel saving 'smart' charging systems. While I understand the parasitic draw happens when the vehicle is OFF, the fact that the charging system does not provide FULL CHARGE at the start of the vehicle and MAINTAIN THAT FULL CHARGE until the battery is up to snuff; is a very common set up in the charging parameters set by most manufacturers so less strain can be put on that alternator to squeeze out those few drops. Kinda @$$ backwards. This is usually why short trips and infrequent trips with the vehicle causes battery issues.
The alternator should never go into 'smart charging' until the battery is actually fully charged! Did the dealership even test the alternator to verify it was even functioning properly and providing proper charging voltage at various intervals??
The parasitic draw and the lack of providing full voltage charging, is just a recipe for failure.

As others have posted there is/was a TSB regarding the 3G telematics constantly trying to phone home with the mother ship (SOA), and this was the cause of many dead batteries. Assuming your vehicle has one of the older DCMs, this needs to be replaced.

However, to verify through process of elimination, your new installed cameras are NOT the reason for the parasitic draw; I would pull the fuse or disconnect that camera system temporarily and see if the battery holds a charge once it has been fully charged. If it still drains after disconnecting the cameras, then a dealer or shop visit is in order.

Unless your alternator, grounding harness, or your battery posts are totally corroded, I do not see how the one dealership stated SALT from the roads was the cause?? Did they find something corroded thru to come to this conclusion??
Did they do any actual parasitic draw testing? You may want to try a different shop, as 'salt from the road' is a weak excuse without proof to the consumer.

 

I can confirm that the battery is undercharged. I drive every day, but my ESS (Engine Stop-Start) doesn’t engage anymore.
One of the common reasons for ESS to stop working is a low battery. I have to drive for an hour or more before the first ESS activation event occurs.
I don’t have testing equipment to confirm it, but I’m seeing the same symptoms on both cars. I’ve stopped turning off the ESS at startup since it doesn’t function anyway. Not complaining—honestly, the feature is as useless as indicators on a BMW.

 

1. Short Drives; you need to drive more than 60mins to fully charge up the battery from 70% state of charge. Just to give you an idea.

So if you drive a little <30mins daily, your battery will never be fully charged ever. Eventually, deplete overtime. It's like the stock market keeps going down on the graph.

Below is the log driving in the morning (dark winter months) with headlights fully on. Imagine, daylight with only 50% DRL. Battery will take even longer to charge up because the alternator doesn't kick into high gear at 14v.

If you look at the graph below here, my headlights sensor switch on automatically when it gets dark and you see the battery SoC above graph starts to go up between 17-18 hour mark. Otherwise it will stay constant straight line.

I use "ANCEL BM200 12V Car Battery Tester" from Amazon, it logs your battery 24/7. You can pull that log once you open the app and connect the bluetooth.

That device is installed on my battery, keep it there.

2. Bad Alternator.

3. Force charging 14v; turn on your headlights even in day time driving.

 

1. Short Drives; you need to drive more than 60mins to fully charge up the battery from 70% state of charge. Just to give you an idea.

So if you drive a little <30mins daily, your battery will never be fully charged ever. Eventually, deplete overtime. It's like the stock market keeps going down on the graph.

Below is the log driving in the morning (dark winter months) with headlights fully on. Imagine, daylight with only 50% DRL. Battery will take even longer to charge up because the alternator doesn't kick into high gear at 14v.

View attachment 326070

If you look at the graph below here, my headlights sensor switch on automatically when it gets dark and you see the battery SoC above graph starts to go up between 17-18 hour mark. Otherwise it will stay constant straight line.

View attachment 326071

I use "ANCEL BM200 12V Car Battery Tester" from Amazon, it logs your battery 24/7. You can pull that log once you open the app and connect the bluetooth.

That device is installed on my battery, keep it there.

2. Bad Alternator.

3. Force charging 14v; turn on your headlights even in day time driving.

Excellent plotted proof!!

 

An automotive technician with experience in electrical/electronics problems may find the problem. Perhaps the same person having a digital oscillioscope with recording capabilities to record 24hrs(?) may see a pattern when battery discharge occurs from; greater than parasitic drain (continual or periodic) over a time span.

Experts are out there, somewhere.

 

Do you subscribe to Sirius XM? We ultimately determined that was the parasitic drain in one of our cars. Canceled it and the problem stopped

 

Suggest parasitic drain test to find where the voltage is going.
"should not still be drawing power."
My first look would be to look at the circuit the Best Buy install is on.
Then it is fuse by fuse.

 

My bet is it's a DCM issue tied to Starlink. Take to dealer. Your car DCM may be covered by Subaru extended warranty for this issue. My 2019 Outback had sever battery drain issue and it was repaired at no cost. The name for the battery drain is called "DCM parasitic" drain. Google for full details.

 

 

I have a 2021 Crosstrek premium, and have had three battery replacements after 1 year and a half of use. Take it or leave it this is what I found out from an electronics technician. I had subscribed to starlink for emergencies. The starlink system automatically calls up to the satellite every 30 minutes to make sure there is a receiving station operable. This in turn burns up battery juice all night long, and if you put on extremely low mileage like I do since I live in the city, your battery is under a constant discharge. My remedy to my problem as follows: turned off all unnecessary lighting inside the cab, killed my subscription to starlink emergency services, put in a Sears die hard AGM platinum battery, and once a month use a smart charger to top the battery off to 100%. After one year with the new AGM battery I've had no problems by following that procedure. P.S the dealer and the AAA mechanic and a few others have told me I simply do not drive the car long enough per month, and all agreed including the Subaru technicians that the starlink system his problematic... Especially if you park your car in a concrete garage. The starling system will continually keep calling up to the satellite to try to establish a connection

 

The issue is the Starlink system. Starlink constantly searches for the no longer available ATT 3G signal. If the dealer is not aware, please contact Subaru. Subaru settled lawsuits and agreed to extended warranties for this issue (parasitic battery drain). It's not your battery or alternator. The dealer will load test the electrical system and install a jumper box to eliminate the non-stop Starlink excessive battery drain. Majority of dealers are very aware of the issue and stock the jumper boxes.
Good luck.

 

Ask your Subaru dealer and/or search for these TSBs on the Internet:
TSB 15-291-22, TSB 15-318-24R, TSB 15-317-24 and 15-312-23R.
There may be more???
I just keep my 2024 on a battery charger while it is parked. Problem solved.