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Anyone having trouble with a bad battery or am I just unlucky? After about 1,000 miles the battery on my new 2020 OB Ltd battery went completely dead. Local dealership tested the battery out and said the battery test failed and they replaced with a new battery and again the car didn't start just 4 days after new battery is installed. Dealership says it might be a alternator issue and they are checking the vehicle. Is this an electrical issue? Has anyone else experienced the same thing?
 

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2020 OB Limited, Titanium & Magnetite Grays
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Lots of forum reports about the LN2 battery failing. Seems there are two batteries, 620 ah is the first issue and newest is labeled 649 ah. Do you know which version failed on your vehicle?
 

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2020 Outback Onyx XT
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Anyone having trouble with a bad battery or am I just unlucky? After about 1,000 miles the battery on my new 2020 OB Ltd battery went completely dead. Local dealership tested the battery out and said the battery test failed and they replaced with a new battery and again the car didn't start just 4 days after new battery is installed. Dealership says it might be a alternator issue and they are checking the vehicle. Is this an electrical issue? Has anyone else experienced the same thing?
Seems to be common:


 

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2020 OB Limited, Titanium & Magnetite Grays
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ArF193...First Installed battery is 620 ah and that's the one failed
I thought the factory builds had switched over to the 640 Ah? When did you take delivery and when was your OB built?
Mine was built Nov 2019 and has the 620 battery without known issues so far. I put in effort to avoid battery low charge conditions, but no matter what I do it always seems to settle at 11.9v after parking 1-2 days.
 

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20 Outback Limited XT 13 Outback 3.6R Limited
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I thought the factory builds had switched over to the 640 Ah? When did you take delivery and when was your OB built?
Mine was built Nov 2019 and has the 620 battery without known issues so far. I put in effort to avoid battery low charge conditions, but no matter what I do it always seems to settle at 11.9v after parking 1-2 days.
Mine Limited XT was built in January of this year, and also had the 620. Not sure if they changed at the factory, or only are using the replacement 640 for people who have issues.
 

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2020 OB Limited, Titanium & Magnetite Grays
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Mine was built in December and I took the delivery in February this year
If you have about 1K miles since Feb then your driving is not enough to keep the battery charged to the desired level. That added to a questionable LN2 620Ah battery may have been a deadly combination for the battery. Subaru and Consumer Reports recommend starting/running or highway driving the vehicle for 30 minutes per week. There are smart chargers designed to slow charge an AGM battery. I hook up a battery tender, AGM approved, one day a week until it reads fully charged.
 

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2020 Outback Limited
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March build, non-XT, 620 battery here. Car has sat for a week twice since I've had it and it fired right up each time. I'm thinking there was a batch of bad 620 batteries perhaps? Great, now I just jinxed myself :)
 

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2020 OB Limited, Titanium & Magnetite Grays
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Forgot to state that the XT has a higher output alternator than is used with the 2.5L engine. This is stated in the manual.
 

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I have a sneaking suspicion that auto start/stop is making our battery situation worse. Not only does it take up more electricity to restart the car, while the car is stopped it's not charging, and the HVAC fan is blowing, headlights, infotainment, whatever else is consuming electricity continues to drain.
 

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19 2.5i OB LTD w/SSD Strt Twr Brc + OEM 19mm RSB
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Sometimes "free" isn't free at all. I'd just go buy myself a decent battery. I did for my 2019 2.5i. With COVID-19, it wasn't getting driven a lot, but it should have been enough to turn the engine over. It cost me about $120 for an EverStart Maxx 34N. I also purchased one of those very small jump devices and carry it in the car just in case.
 

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2020 Outback Limited
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I have a sneaking suspicion that auto start/stop is making our battery situation worse. Not only does it take up more electricity to restart the car, while the car is stopped it's not charging, and the HVAC fan is blowing, headlights, infotainment, whatever else is consuming electricity continues to drain.
Isn't that why they used an AGM battery to handle the additional stress? And why the system only kicks in when the conditions are "right" as far as the car is concerned? ASS has been around for quite a while from various manufacturers, I think by now they probably have the algorithms figured out. I had it on both of my previous BMWs for 3 year leases, and never had a battery issue or anything else ASS related. Long-term who knows though?

At least BMW lets you disable ASS permanently if you so choose :)
 

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Isn't that why they used an AGM battery to handle the additional stress? And why the system only kicks in when the conditions are "right" as far as the car is concerned? ASS has been around for quite a while from various manufacturers, I think by now they probably have the algorithms figured out. I had it on both of my previous BMWs for 3 year leases, and never had a battery issue or anything else ASS related. Long-term who knows though?

At least BMW lets you disable ASS permanently if you so choose :)
Subaru uses a cheaper EFB battery instead of AGM, which is another issue.
 

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2020 OB Limited, Titanium & Magnetite Grays
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I have a sneaking suspicion that auto start/stop is making our battery situation worse. Not only does it take up more electricity to restart the car, while the car is stopped it's not charging, and the HVAC fan is blowing, headlights, infotainment, whatever else is consuming electricity continues to drain.
Lots of trade-offs and they are not in the favor of a long time owner. Numerous start/stops wears the hardware. From what I can determine from observations and measurements I offer the following. My alternator produces less amps than the XT so observations due to algorithm changes may be different. My vehicle likes to have the battery at 11.9V. I can't find the battery at full charge, 12.6V, unless I have charged it with an external charger. When the S/S kicks in, and the battery is at 11.9V, the S/S will keep the engine off until the battery is about to drop to 11.8V. It then starts before the stop is complete thus reducing some benefit of the S/S. The point is that apparently if the battery had more than 11.9V the engine stop would last longer and it should last longer (not related to the A/C temp rise need). My conclusion is that the stop time is often too short in time. Also, I don't know why the battery is most often at 11.9V; if I take the vehicle on a long drive on the hwy my battery never shows 12.6V when the engine has stopped.
 

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2020 Outback Limited XT, 2013 Outback Limited 3.6R
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Like others, I'm afraid to jinx myself, but I've had no battery issues, despite minimal trips these past few months. I have the older version, the 620, from Oct delivery (I think the battery is from Aug, but not 100% on that date).
I do have a really good CTEK charger (will full-slow charge, then maintain, and also recover/de-sulfite, has bailed out numerous older batteries, good investment, for me), that I've used a couple of times, since March, but mostly it's just been a few short trips, here/there.
I bet there was a batch of batteries with some bad solders, on a few plates or something, as there seems to be a definite set of failures/non-issues, for the same batteries; I'm pretty sure I've seen this reported for both the 620/640 series.
I plan to replace with an Optima, whenever it dies, I've had fantastic reliability with their batteries, spanning 25 years or so, so I'll figure out whatever size will shoe-horn in, and that'll be the deal. I've had excellent luck with Subaru OEM batteries though, despite being plain old lead-acid units, I don't think I've had one last < 5 years, over a lot of Subarus now...
 

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I also have never had a problem with Subaru OEM batteries, have a CTEK charger, and the 620 battery in my early production 2020 Outback. My battery has never failed to start, but I can't help but feel like something's wrong when my auto stop/start turns off the engine and then re-starts it a few seconds later, giving it no chance of saving substantial fuel. I don't know if the short stop-times are due to battery weakness, or due to normal proper functioning. If the thing stayed off until I needed to go, I would probably not get rid of it. I'm all for reducing emissions and saving fuel - but at least on my car, I doubt it's reducing emissions or saving fuel. It doesn't stay off long enough to do that. I can be at a 4 minute stop light and the start/stop will have the engine off for 5 seconds of it.
 

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2020 OB Limited, Titanium & Magnetite Grays
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Since Oct 19, 2019 we have had almost 4 hours of stop time in 3200 miles and no issues with the battery or other components.
I expect the starter motor, bendix gears and other related parts will fail sooner than I have seen on my non ASS vehicles. Point is that MTBF for ASS related parts will be shorter or more expensive in the long run for this vehicle. One example of extra expense is the LN2 3-yr Battery at $250 when a flooded 6 yr battery can be had for $60-70.
 

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2020 Outback Limited XT, 2013 Outback Limited 3.6R
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Yeah, @SilverOnyx, I totally concur, although I suspect most of those really-short start/stops are for things like AC/heat/brake-pedal-pressure-variation.
Unfortunately, a standard OBD II reader can't see the codes for these, I suspect you need something that gathers Subaru-specific codes, and I bet it's not cheap...

I pre-ordered the AutoStop-Eliminator.
Like some, I'd really like to fully understand the algorithm it's using (having worked on h/w and s/w design for most of my life...), but really, at this point, I just want the madness to stop ;-]
I'm fine with those who don't care about the implementation, or those who think the 2-3 step disable is fine, for them, that's all good, I just want mine to NOT auto-not-start/stop...
And yeah, I truly don't believe that all these little-tiny starts/stops are not beating-on-various components, including, but not limited to, the poor battery, which really was never designed with auto-S/S in mind. They may not shorten the lifetime by much, or maybe by quite a bit, that part will play-out over a good many years, we'll see...

I've said it in a few other threads, my next car will have at least a mild-hybrid model, and I really, really hope it'll be a Subaru.
 
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