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I have seen this thread before, but haven't had an issue until today. The battery on my 2018 Outback 2.5 was dead today 6/18/20, and I looked up battery issues in the manual. I searched the site but don't see the "battery drainage prevention function" mentioned here. The manual indicates, when turned on, this function will cut off the lights after 20 minutes. According to my manual, this function can only be changed by a Subaru dealer. What?!?!

Has anyone looked into this as a possible solution? With this function turned on, would the tailgate up still be a power drain issue?

FYI Background on my battery issue: I had my tailgate up for several hours on 6/9/20 while I installed a trailer hitch and wiring harness. The battery was low and it was slow to start. Only drove a couple of miles over the next couple of days, then drove over 350 miles each day on 6/12/20 and 6/15/20. I did not drive any between 6/16/20 and 6/18/20, when I discovered the battery was dead. Seems to me the battery would be sufficiently recharged during those long drives. Bought the car a month ago with 27k miles, certified preowned. Still under manu warranty. Battery is a Johnson Controls, but don't know if it is original. So, don't know if I need a new battery or if it is draining somehow. Would like to think the battery would last longer than 2 years.
 

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I have seen this thread before, but haven't had an issue until today. The battery on my 2018 Outback 2.5 was dead today 6/18/20, and I looked up battery issues in the manual. I searched the site but don't see the "battery drainage prevention function" mentioned here. The manual indicates, when turned on, this function will cut off the lights after 20 minutes. According to my manual, this function can only be changed by a Subaru dealer. What?!?!

Has anyone looked into this as a possible solution? With this function turned on, would the tailgate up still be a power drain issue?

FYI Background on my battery issue: I had my tailgate up for several hours on 6/9/20 while I installed a trailer hitch and wiring harness. The battery was low and it was slow to start. Only drove a couple of miles over the next couple of days, then drove over 350 miles each day on 6/12/20 and 6/15/20. I did not drive any between 6/16/20 and 6/18/20, when I discovered the battery was dead. Seems to me the battery would be sufficiently recharged during those long drives. Bought the car a month ago with 27k miles, certified preowned. Still under manu warranty. Battery is a Johnson Controls, but don't know if it is original. So, don't know if I need a new battery or if it is draining somehow. Would like to think the battery would last longer than 2 years.
the longer light power save might contribute somewhat - but people have measured increased draw that does not appear to go away when the gate is open even with the lights off (without something in the latch to make it think the gate is closed). The Body Integrated Unit is drawing power for something was the consensus - and it's enough to drain the OEM battery within a few hours down to where the car will not crank.
 

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the longer light power save might contribute somewhat - but people have measured increased draw that does not appear to go away when the gate is open even with the lights off (without something in the latch to make it think the gate is closed). The Body Integrated Unit is drawing power for something was the consensus - and it's enough to drain the OEM battery within a few hours down to where the car will not crank.
Thanks. From what I was reading, it appeared there was more to it than just the lights. I'll try the latch trick next time I have it open. Also read some about charging batteries and it appears driving may not sufficiently recharge the battery. I'm giving it a charge now. Mine appears to be original, so next step will be to replace. Appreciate the feedback.
 

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(Australian spec) 2019 MY19 Outback 3.6R CVT.
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I searched the site but don't see the "battery drainage prevention function" mentioned here. The manual indicates, when turned on, this function will cut off the lights after 20 minutes. According to my manual, this function can only be changed by a Subaru dealer. What?!?!

Has anyone looked into this as a possible solution? With this function turned on, would the tailgate up still be a power drain issue?
I’m surprised that that function isn’t enabled. Going by my battery load tests results our Australian spec Outback must have that enabled from the factory. [Edit] I checked the 2016 & 2019 US Owner's Manuals & they both state that the factory default setting for the 'battery drainage prevention function' is operational (enabled). [/Edit]

Some time ago with the rear hatch open on our 2019 Outback 3.6R I measured 4.15A drain on the battery. At the 20 minute mark this dropped to 3.40A when the rear hatch light & the dome light timed out. I have an LED in the rear hatch light so those figures are specific for that configuration. But if I had the original incandescent globe in the rear hatch light instead of the LED, by my calculations the initial drain with the hatch open up to the 20 minute mark should be 4.98A instead of 4.15A, & the post 20 minute 3.40A figure should be unchanged.

So it won’t completely solve the rear hatch drain problem but it will delay the time it takes to discharge the battery down to a low state of charge with the hatch open.
 

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On the 2020s with power lift gate, the owner's manual says if you hold the power rear gate lock button for more than two seconds, it locks all the doors (including rear gate), but disables the auto closing of the gate. I assume this is the same as manually flipping the hatch latch closed with a screw driver (which I tried tonight and it shut off the latch open signal on the gauge cluster). Will test tomorrow, but assume it that works, it should limit the drain on the battery?
 

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Very interesting. I'll have to look at my 2018 manual to see if there is anything mentioned about this. Could be a more recent "fix" for this problem. Thanks.
 

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Very interesting. I'll have to look at my 2018 manual to see if there is anything mentioned about this. Could be a more recent "fix" for this problem. Thanks.
on the 2020 I'm assuming he's talking about the second button there inside the rear gate that locks the car and closes it (with a short press). The gen5 didn't have that feature, and after using it for a week on a loaner, it's pretty useful.
 

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On the 2020s with power lift gate, the owner's manual says if you hold the power rear gate lock button for more than two seconds, it locks all the doors (including rear gate), but disables the auto closing of the gate. I assume this is the same as manually flipping the hatch latch closed with a screw driver (which I tried tonight and it shut off the latch open signal on the gauge cluster). Will test tomorrow, but assume it that works, it should limit the drain on the battery?
Holding the rear gat lock button did not automatically close the latch on the rear gate, just stopped it from automatically closing while locking the rest of the doors, so dome lights and open door monitor. So looks like manually closing the latch is still the work around, running a test on that today to confirm if battery still drains or not. (Nothing fancy, I don't have any tools to measure amps, only going to leave it open for 6-8 hrs and then see if I can start it up)
 
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