2018 Outback with excessive battery drain

[MSDS]

2018 Outback with excessive battery drain that results in a dead battery (even brand new) within 7 to 10 days of left parked either in garage or at airport while on a business trip. Now on our 4th battery and Subaru dealership where vehicle was purchased new has provided no solution except drive it daily for a minimum of 45 minutes or apply a maintenance charger to the battery each night. Remote start and rear wiper no longer works as well as the power windows. Subaru dealership has been of no help with this vehicle.

 

[Dick Foster]

I think there's a service bulletin. Something to do with Starlink or some such trying to use an obsolete cell service draining the battery in short order. The dealer network should know all about it. If not you've got enough info to search it out now.

 

[MSDS]

I think there's a service bulletin. Something to do with Starlink or some such trying to use an obsolete cell service draining the battery in short order. The dealer network should know all about it. If not you've got enough info to search it out now.

Thank you!

 

[Raymond3006]

This is an Old-Problem; but most of the Forum-Info has aged beyond the Electronic Data Horizon !

In Summary :
(1) The DCM Fuse can be pulled, but it might interfere with non-esential but desirable Electronic Options;
(2) The Alternator can be caused to provide better charging than Subaru Engineered Charging ,
This is done by inserting a Silicon Diode in the ALT-S Fused Circuit going to the Alternator ;
(3) A "Battery-Maintainer" Mini-Charger ($25 on EBay) can be connected semi-permanently to your Battery, which will keep your battery at Max Charge over-night or Over-Weekends. The Mini-Charger also provides De-Sulphate Function, which can be Researched @ www.batteryuniversity.com .

You can attempt to have Subaru solve this , and will eventually cost you Several-Hundred to Over A Thousand Dollars, and 10-100 Hours of your personal time chasing back-and-forth to the Subaru ER (aka, The Service Department !)

Or you can DIY , and work your way thru the Three-Options, in any order that you decide fits your Life-Style !!!!

For Learning , you can use the Key-Words in my 1-2-3 Options, and do GOOGLE-Searches for the more Technical Installation Details; the Choice is yours !

If you choose to follow-up in this Forum, I am not the only one who can respond ....... ! Back in the Mid-20-Teen-Years , this was all over the Subaru Forums .... !

GO-FOR-IT ... !!!!

 

[Raymond3006]

Forgot : I also changed from the OEM Battery , to a WalMart EverStart MAXX Group 34N battery : that unit will fit the Battery Support System , but you will have to throw away (or Store - !) that "&^%#%" Battery-Wrap Contraption , and may need to "modify" the Hold-Down-Bolt to get that "hook" out of the Way

This heavy duty battery will get you about triple-amount of Battery-Reserve, compared to the OEM (forget the OEM theoretical New-Battery capacities , as the batttery-wrecking-charging-design will never allow you to have a fully charged battery, as you already know, by NOW !!!). With the OEM Battery , and the OEM Charging Design , the OEM Battery is repeatedly at or just over 50% SOC (State Of Charge : see Battery_University, above). This repeated under charging will ruin most OEM Batteries in +/- 2-Years ..... !!!!

 

[MSDS]

This is an Old-Problem; but most of the Forum-Info has aged beyond the Electronic Data Horizon !

In Summary :
(1) The DCM Fuse can be pulled, but it might interfere with non-esential but desirable Electronic Options;
(2) The Alternator can be caused to provide better charging than Subaru Engineered Charging ,
This is done by inserting a Silicon Diode in the ALT-S Fused Circuit going to the Alternator ;
(3) A "Battery-Maintainer" Mini-Charger ($25 on EBay) can be connected semi-permanently to your Battery, which will keep your battery at Max Charge over-night or Over-Weekends. The Mini-Charger also provides De-Sulphate Function, which can be Researched @ www.batteryuniversity.com .

You can attempt to have Subaru solve this , and will eventually cost you Several-Hundred to Over A Thousand Dollars, and 10-100 Hours of your personal time chasing back-and-forth to the Subaru ER (aka, The Service Department !)

Or you can DIY , and work your way thru the Three-Options, in any order that you decide fits your Life-Style !!!!

For Learning , you can use the Key-Words in my 1-2-3 Options, and do GOOGLE-Searches for the more Technical Installation Details; the Choice is yours !

If you choose to follow-up in this Forum, I am not the only one who can respond ....... ! Back in the Mid-20-Teen-Years , this was all over the Subaru Forums .... !

GO-FOR-IT ... !!!!

Thank You! This was our first and will be our last Subaru due to zero trust and confidence in their design engineers.

 

[Dick Foster]

This is an Old-Problem; but most of the Forum-Info has aged beyond the Electronic Data Horizon !

In Summary :
(1) The DCM Fuse can be pulled, but it might interfere with non-esential but desirable Electronic Options;
(2) The Alternator can be caused to provide better charging than Subaru Engineered Charging ,
This is done by inserting a Silicon Diode in the ALT-S Fused Circuit going to the Alternator ;
(3) A "Battery-Maintainer" Mini-Charger ($25 on EBay) can be connected semi-permanently to your Battery, which will keep your battery at Max Charge over-night or Over-Weekends. The Mini-Charger also provides De-Sulphate Function, which can be Researched @ www.batteryuniversity.com .

You can attempt to have Subaru solve this , and will eventually cost you Several-Hundred to Over A Thousand Dollars, and 10-100 Hours of your personal time chasing back-and-forth to the Subaru ER (aka, The Service Department !)

Or you can DIY , and work your way thru the Three-Options, in any order that you decide fits your Life-Style !!!!

For Learning , you can use the Key-Words in my 1-2-3 Options, and do GOOGLE-Searches for the more Technical Installation Details; the Choice is yours !

If you choose to follow-up in this Forum, I am not the only one who can respond ....... ! Back in the Mid-20-Teen-Years , this was all over the Subaru Forums .... !

GO-FOR-IT ... !!!!

The series diode in the Alt S (sense) wire is intended to boost the charging voltage a bit higher for use with AGM batteries. Typically 0.6 V for a silicon diode.

This can only be done if charging voltage is sensed external to the alternator and not internally.

This would be a bad thing to do for normal wet cell automotive batteries as it would tend to overcharge, sulfate and shorten battery life.

Only do this mod if you've installed an AGM (absorbed glass mat) battery.

If you want a good AGM battery, IMHO Odyssey makes the best, by far. I ran two of em in my rock crawler.

In it, the charging circuit was external to the alternator which was also used as a power supply for welding. I had removed the internal voltage regulator from the alternator as it needed to be moved to the on-board welder. The alternator was also rewound to provide more power.

 

[Raymond3006]

The series diode in the Alt S (sense) wire is intended to boost the charging voltage a bit higher for use with AGM batteries. Typically 0.6 V for a silicon diode.

This can only be done if charging voltage is sensed external to the alternator and not internally.

This would be a bad thing to do for normal wet cell automotive batteries as it would tend to overcharge, sulfate and shorten battery life.

Only do this mod if you've installed an AGM (absorbed glass mat) battery.

If you want a good AGM battery, IMHO Odyssey makes the best, by far. I ran two of em in my rock crawler.

In it, the charging circuit was external to the alternator which was also used as a power supply for welding. I had removed the internal voltage regulator from the alternator as it needed to be moved to the on-board welder. The alternator was also rewound to provide more power.

An ALT-S designation is the Fact of this concept ; if it is Labeled as ALT-S , then the Diode Mod WORKS !

I have been running Two ( 2-!! ) Series Diodes for years and my Lead-Acid Battery is now 5-Years-Old , and it's SOC is still @ 90% .... !!!!!! This concoction pushes the Alternator Charging to 14.08-Volts , which is also the Same-Voltage that my De-Sulphation Battrey Maintainer provides, when I use it in the Winter Time.

These FACTS are Provable and Productive for my Vehicle ; and are the result of Subaru's 2016 disaster in my Vehicle ; if they had not been so obstinate , I would never have gone down the Path that took me to where I am Today :
Fear, and spreading theoretical Disasters is a problem in/on these Forums.
Cowards Die A Thousand (battery) Deaths ; But The Brave (owners batteries) Only Die Once ;

HINT - In a Previous Life, I used this same Mod in a 2001 Buick LaSabre , with an Origional OEM Die-Hard-Battery under the rear seat, and that battery went with the Vehicle when I gave it to a Relative in 2023 .... : so forget about how it destroys batteries !

 

[Raymond3006]

I think there's a service bulletin. Something to do with Starlink or some such trying to use an obsolete cell service draining the battery in short order. The dealer network should know all about it. If not you've got enough info to search it out now.

Subaru sold vehicles with the 3-G Cell Service for months AFTER the 3-G-System was already DEAD ! Then refused to replace the crap OEM System that all the world knew was going to be Shut-Down for almost 5-YEARS previously !!!!!!!!!
Subaru : the HEIGHT of Arrogance !!!

 

[Dick Foster]

Subaru sold vehicles with the 3-G Cell Service for months AFTER the 3-G-System was already DEAD ! Then refused to replace the crap OEM System that all the world knew was going to be Shut-Down for almost 5-YEARS previously !!!!!!!!!
Subaru : the HEIGHT of Arrogance !!!

I just gave Starlink the boot today. It seems they just won't or can't get it right.
The reason I dumped it is because I plugged a Scangauge in the OBDII port to moniter oil temp, tranny temp etc and somehow that sets off the Starlink SOS button. Now that is a crap design on Starlinks part. It's not just Scangauge either, it's anything.