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2019 Sport with eyesight (CVT)
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Discussion Starter #1
Hi,

Basically my question is in title. If anybody can confirm from real-world experience on 2018+ model that this “Battery drainage prevention function” from user manual does NOT work when dome light is left in ON position?

(Kids were playing before exit the car, than it was not driven for 1 full day and then next morning with -15C the light was still emmm…lightly visible and definitely ON but push-button or anything else did not give signs of life and obviously won’t start. Jump-started and driven 30 min than topped up with a charger albeit in cold unheated shelter. Measured 12.4V afterwards. Will charge more when it gets to 0C at least)

Thanks!
 

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Hi,

Basically my question is in title. If anybody can confirm from real-world experience on 2018+ model that this “Battery drainage prevention function” from user manual does NOT work when dome light is left in ON position?

(Kids were playing before exit the car, than it was not driven for 1 full day and then next morning with -15C the light was still emmm…lightly visible and definitely ON but push-button or anything else did not give signs of life and obviously won’t start. Jump-started and driven 30 min than topped up with a charger albeit in cold unheated shelter. Measured 12.4V afterwards. Will charge more when it gets to 0C at least)

Thanks!
No real-world experience but there have been a lot of posts here lately about the OEM battery not handling cold weather. I upgraded ours to an Odyssey Extreme AGM a couple of years ago, no problems since.
 

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2019 Subaru Crosstrek Limited
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583 Posts
Hi,

Basically my question is in title. If anybody can confirm from real-world experience on 2018+ model that this “Battery drainage prevention function” from user manual does NOT work when dome light is left in ON position?

(Kids were playing before exit the car, than it was not driven for 1 full day and then next morning with -15C the light was still emmm…lightly visible and definitely ON but push-button or anything else did not give signs of life and obviously won’t start. Jump-started and driven 30 min than topped up with a charger albeit in cold unheated shelter. Measured 12.4V afterwards. Will charge more when it gets to 0C at least)

Thanks!
It’s real. I’ve left the dome like on one time and it turned itself off. However, that was roughly a year ago but I always make sure to not leave any lights on...
 

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2019 Sport with eyesight (CVT)
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Discussion Starter #4
No real-world experience but there have been a lot of posts here lately about the OEM battery not handling cold weather. I upgraded ours to an Odyssey Extreme AGM a couple of years ago, no problems since.
Thanks for your reply.

Well the complete story is that OEM battery started acting up in las summer, wasn’t even cold yet and I changed it in Oct. Before changing tried to charge multiple times but it wasn’t holding the charge for more than 1-2 days. So I know firsthand OEM is not good. But it made through 2 winters already and they were much more colder than this winter. With pandemic and complete WFH equal to low usage I could understand. Anyways after changing battery no problems….till this week. So now it’s second battery, almost new, sticker says manufactured Oct 2020 and much more capable (700 CCA vs 470 CCA in OEM ) that was brought to its knees by my Crosstrek. I know user manual says do not leave any lights ON to avoid discharge, but still. I mean we are in 21st century and I even have remote start on my phone and can see battery voltage anytime. But no notifications of battery draining over relatively short time like 36 hours span this week. Sorry for venting, It’s my first truly new car and starting to disappoint unfortunately.

That’s why I’m asking specifically about real experiences with this drainage prevention function. And I may be asking too much because when on DOOR as per owner manual and IF this function works, people might not even notice, because their battery is ok after all.
 

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2019 Sport with eyesight (CVT)
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Discussion Starter #5
It’s real. I’ve left the dome like on one time and it turned itself off. However, that was roughly a year ago but I always make sure to not leave any lights on...
Excellent, thank you for your input. Afterwards how did you notice it was on? Did it light up at next start?
 

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2019 Subaru Crosstrek Limited
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Thanks for your reply.

Well the complete story is that OEM battery started acting up in las summer, wasn’t even cold yet and I changed it in Oct. Before changing tried to charge multiple times but it wasn’t holding the charge for more than 1-2 days. So I know firsthand OEM is not good. But it made through 2 winters already and they were much more colder than this winter. With pandemic and complete WFH equal to low usage I could understand. Anyways after changing battery no problems….till this week. So now it’s second battery, almost new, sticker says manufactured Oct 2020 and much more capable (700 CCA vs 470 CCA in OEM ) that was brought to its knees by my Crosstrek. I know user manual says do not leave any lights ON to avoid discharge, but still. I mean we are in 21st century and I even have remote start on my phone and can see battery voltage anytime. But no notifications of battery draining over relatively short time like 36 hours span this week. Sorry for venting, It’s my first truly new car and starting to disappoint unfortunately.

That’s why I’m asking specifically about real experiences with this drainage prevention function. And I may be asking too much because when on DOOR as per owner manual and IF this function works, people might not even notice, because their battery is ok after all.
What kind of remote start do you have? Is it aftermarket?

I have sympathy for your situation as well. As Astro said, others have had a bad experience with their OEM battery but there is no excuse for a 700 CCA battery to go bad now. Maybe it's a defective one? You should look into a warranty claim on that battery.
 

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Excellent, thank you for your input. Afterwards how did you notice it was on? Did it light up at next start?
I got into the car, and as I was settling in I noticed the light was on. It was on for about five hours since I was working that day. The car is parked in the mall's underground parking so it may have helped my situation since the car wasn't out in the cold.
 

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Thanks for your reply.

Well the complete story is that OEM battery started acting up in las summer, wasn’t even cold yet and I changed it in Oct. Before changing tried to charge multiple times but it wasn’t holding the charge for more than 1-2 days. So I know firsthand OEM is not good. But it made through 2 winters already and they were much more colder than this winter. With pandemic and complete WFH equal to low usage I could understand. Anyways after changing battery no problems….till this week. So now it’s second battery, almost new, sticker says manufactured Oct 2020 and much more capable (700 CCA vs 470 CCA in OEM ) that was brought to its knees by my Crosstrek. I know user manual says do not leave any lights ON to avoid discharge, but still. I mean we are in 21st century and I even have remote start on my phone and can see battery voltage anytime. But no notifications of battery draining over relatively short time like 36 hours span this week. Sorry for venting, It’s my first truly new car and starting to disappoint unfortunately.

That’s why I’m asking specifically about real experiences with this drainage prevention function. And I may be asking too much because when on DOOR as per owner manual and IF this function works, people might not even notice, because their battery is ok after all.
I've done some pretty extensive tests and the drain on the battery is negligible. There are loads of threads here already... 😸
 

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2019 Sport with eyesight (CVT)
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Discussion Starter #9
What kind of remote start do you have? Is it aftermarket?

I have sympathy for your situation as well. As Astro said, others have had a bad experience with their OEM battery but there is no excuse for a 700 CCA battery to go bad now. Maybe it's a defective one? You should look into a warranty claim on that battery.
Yes, it is aftermarket but installed by the dealer before I took new car ownership. I suspect it may interfere with drainage prevention function but how to prove it?
 

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Yes, it is aftermarket but installed by the dealer before I took new car ownership. I suspect it may interfere with drainage prevention function but how to prove it?
I’m not sure how you would be able to say it’s interfering with the system.
 

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Sorry you're having a problem with your battery. It's a common problem now that we're not driving as much. There are LOTS of threads here discussing this. Try the search.

Have you taken it to the dealer and asked for a replacement? The "drainage" is negligible.
 

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Before you take it to a dealer, take it to a battery place. They will test it for free, and give you the straight goods. Then take it the dealer and see what they say.
 

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2021 Crosstrek Limited
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Change to LED emitters. There are threads on this. They use around 1/5 energy.
 
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My 2018 battery died several times and then finally wouldn't hold a charge at all. One time it was parked about 36 hours after a 45 minute highway drive, so the battery should have been fully charged. When I came back to the car the battery would barely light up the dome light. I found the rear hatch slightly open. There's piece of rubber weather stripping which sometimes sits up a bit and blocks the latch from fully engaging. (Actually, it is the seam in the weather strip being right by the latch which is the problem). Anyhow, from that I surmised the rear hatch not being fully closed will defeat the protection scheme somehow. I have left the hatch fully open and the interior lights do indeed automatically turn off after a while (30 minutes?).

So, the battery drain protection logic may be less than perfect.

You definitely have continuous parasitic drain from your battery in any modern car. Your remote start system might use more than you realize, and if your battery is damaged it could be enough to just kill it.

Also, it is possible an accessory has started to draw more than it should. I have a traffic cam system on my motorcycle which had a failure in the power supply that left the whole thing powered up instead of going into a very low standby power state. It happened to a lot of people, not just me.

If I were you, I'd have the parasitic current measured to see what the load on the battery is when the car is turned off. Also, get one of those cheap voltmeters you plug into the cigarette lighter. It will give you valuable information.
 

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I've done some pretty extensive tests and the drain on the battery is negligible. There are loads of threads here already... 😸
Negligible only when it is locked. But much more drain when it is unlocked as some systems seem to power up expecting you to soon start the engine.
 

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Negligible only when it is locked. But much more drain when it is unlocked as some systems seem to power up expecting you to soon start the engine.
Yes, I've noticed that. Ours is always locked unless we're about to drive somewhere.
 

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2020 Crosstrek Limited
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Negligible only when it is locked. But much more drain when it is unlocked as some systems seem to power up expecting you to soon start the engine.
Also, if you are parked in your garage, the key FOB must be kept a distance away from the parked car, OR the car will sense the FOB's proximity and keep some systems awake.
Finally, there is a procedure to put your FOB into 'sleep mode' and avoid that problem altogether. Hold down the 'lock' button while pressing the 'unlock' button twice. The indicator light should flash four times to let you know that it has entered power saving mode. You must press the 'lock' button or the 'unlock' button to bring the FOB back to normal activity.
 

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Also, if you are parked in your garage, the key FOB must be kept a distance away from the parked car, OR the car will sense the FOB's proximity and keep some systems awake.
Finally, there is a procedure to put your FOB into 'sleep mode' and avoid that problem altogether. Hold down the 'lock' button while pressing the 'unlock' button twice. The indicator light should flash four times to let you know that it has entered power saving mode. You must press the 'lock' button or the 'unlock' button to bring the FOB back to normal activity.
Our condo building has a subterranean garage so not a problem, however, there are other reasons to keep your fobs secured. Thieves are now using repeaters to spoof the signal from the fob and break into cars, or even drive them away...
 
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