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2015 Forester CVT
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25 Posts
Discussion Starter #1
Hey guys is it possible to get a battery size sticky of what sizes will fit on various years.

Our 2015 forester just had its second failure so i want to replace it. I can see from drain test that there is a combination of relatively low capability in the stock battery and an inherent drain (in fact drain varies). Looking at other threads this seems to be relatively high drain even if there is not an electrical fault. So coming up on fourth winter, with a fail last year, and a dead battery with 45 minutes of flashers on without car running, and a usage pattern on this vehicle that won't change, it is time for a new battery

For those of us who don't want to go AGM, but will go with traditional lead using Consumer reports well ranked lead acid batteries, like walmart "Maxx" , and largest size that will fit, it would be good to have a sticky for larger than size 35 stock.

Anyone try larger battery, ie same brand and type but just more cch that will fit/ eg 24 or 27 (and sub model of 24 and 27, ie 'F' 'H" 'T' "R' on a 2015?

I see there are scattered threads on battery issues with this vehicle, but a sticky on size would be good.

Thanks!
 

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2015 Forester CVT
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25 Posts
Discussion Starter #2 (Edited)
has anyone tried 24 or a 24? Threads on earlier model forester indicate type 24 fits.

As we know some same size battery designs get more CCA by using thinner plates and more corrosive acid, whihc is ok for north Dakota and alaska, but is much more sensitive to heat damage and shorter life in places with hot summers. So overall volume matters, more volume equals more plate surface and more CCA without more damage prone thinner plates.

This is a blunt measurement since it may include posts, but still to get the picture on rough volume differences which may matter a lot:
  • type 35 (stock) volume about 488 c/i;
  • type 24F volume is about 671 c/i; and,
  • type 27 volume is about 763 c/i
 

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2016 XT Premium
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285 Posts
Trying to go to a larger battery is a can of worms. The battery bay does have room for larger group sizes. I ran into post location issues when trying to fit a larger Optima battery into mine for camping power. I went with the proper Optima size and will likely never wish it was larger.

It is likely that upgrading to a higher quality battery will solve your issue (the OEM batt from Subaru is garbage in the cold). Pretty much every battery has a higher CCA rating than the Subaru one. Your point is about the volume is interesting but you dont NEED to go to the trouble, and added weight of a larger battery to get the reliability from the vehicle that you seek.

If you really want to pioneer a larger battery swap go right ahead. I had a size 34 Optima Yellow top for a Jeep Wrangler that I was able to plop into my engine bay before its real install. It fit fine physically but the posts on that battery are set back from the edge by 1.5"~ so the OEM battery clamps would not work without some modifications. Something to consider if doing this. Good Luck!
 

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2015 Forester CVT
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25 Posts
Discussion Starter #4 (Edited)
Larger sizes are sometimes just 1/2 inch more in a couple of dimensions and same in say the third. They very often fit. For example in prior model foresters and we have install threads with pics here on this forum of larger than stock sizes that fit.

larger sizes are often better choice than same size with more CCA for its size, since higher CCA can be achieved by doing things that shorten battery life. Often a battery labeled with 20% more CCA will have 200% less CCA in a couple of years in a car in say Florida or Texas summers.

I care as I am in a place with brutally hot summers and very cold winter mornings and I have not attached garage.

There are very often such topic threads on various make cars for this reason.

Wranglers are of course a different animal. Many people buy them to modify them even when there are no issues. i do with my JK. JK wranger has 11 years worth of thousands of guys accessorizing and fixing them, and 11 years of third party custom parts including second battery trays, or larger primary battery trays. My wrangler also has no power use at all when off and these foresters can be drawing 30-50 mA at times and dealerships saying this does not mean anything is wrong.


The economics is simple, yes you can pay 2.5 -3 times with a glass matte battery like a Optima yellow top and get maybe seven years. But in many cars you can simply get a larger lead acid battery for just a bit more as the same price as stock lead acid and have more CCA with that CCA achieved with thicker longer lasting plates.
 

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2015 Forester CVT
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25 Posts
Discussion Starter #6
Put this one in this past spring https://www.batteriesplus.com/battery/car-and-truck/subaru/forester/2016/h4-2.5l-390cca/sli35agmdp.
Seems to have a good warrenty a little expensive but we run a dash cam for 6 hrs. while wife is at work and have had no issues as of yet.
The X2's are made by NorthStar.
Good luck whith what ever you choose.
Cool. That looks like a good alternative to optima if one wants to go group 35 AGM. There are in house brand advance/autozone etc AGMs with good ratings in group 35 size for $140 to $150 though.

By the way I have tested height tolerance under hood of forester with my kids play-doe and there are quite a few groups sizes that will fit, since it looks like you can go up to 1 1/2 inches higher than g35 (although I would cover the positive at that height just in case someone decided to sit on the hood). There is easily enough room for 24F, and 24 F will fit as well.
 

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2014 Premium Manual 6-speed
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34 Posts
I put a walmart everstart maxx 24F in my 2014 because they didn't have the 35N in stock. For the thin plastic tray I slit the corners and folded the edges down, and for the foam battery wrapper I cut one edge and just wrapped it around best I could. Battery fits fine.
 
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