Everything you need to know about your battery issue.

I disagree that this is "everything" you need to know...

AGM batteries are more tolerant of abuse, such as being discharged or high/low temps or the demands of AS/S, and they take up charge faster, which is an issue with the eco charging of modern cars. I suggest you review some of the battery threads here.

They also last longer so, over time, the extra cost is warranted, if you expect to keep your car longer than the warranty period.

Here's another. The OEM battery life can likely be extended through maintenance. Check the water/acid level and add distilled water if low.

medtech said:

1. Technically a battery life span is 2-5 years.
2. If your battery dies earlier than expected, I would blame the extra load put on it by the start/stop system.
3. Yes you can put an aftermarket battery in.
4. No you don’t need an expensive AGM battery.
5. The start/stop can be bypassed with the “auto start stop eliminator”. I have one and I love it.

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FYI - the battery in the cars with stop/star is different. That is to compensate for additional starting. BTW - I have the stop/start eliminator. My theory is the battery should last longer. We shall see.

Battery Guru,

What is the largest size battery that will fit in the battery bay?

subarik said:

Battery Guru,

What is the largest size battery that will fit in the battery bay?

Click to expand...

subarik said:

Battery Guru,

What is the largest size battery that will fit in the battery bay?

Click to expand...

24F Vs 35 Car Battery: What's The Difference? - Car, Truck And Vehicle How To Guides - Vehicle Freak
There are 6 cells in both batteries.

subarik said:

Battery Guru,

What is the largest size battery that will fit in the battery bay?

Click to expand...

Lots of opportunity for innuendo here, LOL. It's not the size that counts, it's the performance...

You need a Group 35 battery and if you have AS/S you need one that's specified for AS/S. A high-end example would be an Odyssey ODP-AGM35

AGM batteries are more expensive but perform better, especially in temperature extremes, and they last longer.

AstroKats said:

Lots of opportunity for innuendo here, LOL. It's not the size that counts, it's the performance...

You need a Group 35 battery and if you have AS/S you need one that's specified for AS/S. A high-end example would be an Odyssey ODP-AGM35

AGM batteries are more expensive but perform better, especially in temperature extremes, and they last longer.

Click to expand...

I would disagree with a few of those points. One of the cheapest upgrades towards reliability one can do to their Subaru is an AGM battery. The factory batteries are garbage. I also run AGM batteries in our BMW and Porsche with great results.

77'911 said:

I would disagree with a few of those points. One of the cheapest upgrades towards reliability one can do to their Subaru is an AGM battery. The factory batteries are garbage. I also run AGM batteries in our BMW and Porsche with great results.

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Couldn't agree more! There are so many posts here about "upgrades" like mudflaps. A decent battery to replace the crappy OEM should be at the top of the list. Especially if you intend to go off road and up into the mountains in the winter.

My original OEM battery is now a bit over 3-1/2 years old. Most of my drives are very short (under 5 miles round-trip). I expect it to last a minimum of 5 years. Maybe I've just had good luck with car and motorcycle batteries, but I've never had one go bad with less than about 7+ years of use. Only my motorcycle batteries live on chargers during the winter, never the Crosstrek's.

AstroKats said:

You need a Group 35 battery and if you have AS/S you need one that's specified for AS/S. A high-end example would be an Odyssey ODP-AGM35

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You can fit larger than G35, which is why I asked what the largest was not what what stock size was.

subarik said:

You can fit larger than G35, which is why I asked what the largest was not what what stock size was.

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I don't think that a larger battery will fit into the heat protective blanket surrounding the OEM battery.
Maybe one just a bit taller. If you remove the heat protector, then many more options are possible.

sas-XV said:

I don't think that a larger battery will fit into the heat protective blanket surrounding the OEM battery.
Maybe one just a bit taller. If you remove the heat protector, then many more options are possible.

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Good point! I would think a high end AGM Group 35 battery would be a better option than a physically larger battery.

sas-XV said:

I don't think that a larger battery will fit into the heat protective blanket surrounding the OEM battery.
Maybe one just a bit taller. If you remove the heat protector, then many more options are possible.

Click to expand...

I tossed the blanket long ago because it started to turn to dust, so personally I wouldn’t have that problem. But I don’t think a larger battery would fit anyway because of the bracket that holds the battery in place. Correct me if I’m wrong, but I believe it’s already a pretty tight fit.

If that's the case, an AGM would be a better option as they tolerate heat better.

I haven't measured but it would be difficult to fit a much bigger battery in there. Again, better to install a better one than a bigger one.

1050 CCA seems unlikely. If you can find one, the Odyssey Extreme is 850 CCA.

Cars today have a battery management system to make sure you dont charge your battery in the name of insignificant fuel mileage savings. Its part of the problem on new cars.