[Yarameme]

@MTforester17,
Sorry, the battery in my 2020 forester is same group size 35 as our old 2010 forester and 2006 Impreza. If they like to save some weight and get better mpg, Subaru engineers would tell us the fat @$$ American to loss some weight. Who ever told you Subaru try to save 5 lb on battery to get better mpg is just BSing you.
btw, Subaru oem Japanese battery is made by Panasonic. Lowest price for acceptable battery to work in as wide of temp as possible.

 

[Marv2]

I was told by a Subaru trained technician that Subaru puts batteries lighter in weight in their new vehicles -- another case of keeping the overall weight of the vehicle as low as possible to get a better score on the epa mpg figure to put in the window sticker and online for when potential shoppers compare cars.

He told me that the dealership will put in a battery with better specs on request when the factory battery fails, but personally recommended that I get an AGM battery. A couple of weeks ago, I left the running lights on (no headlights) for about 10 minutes and needed a jump. The roadside assistance guy told me that he sees a lot of Subarus in his work and recommended I get a replacement from the dealer. I'm seriously thinking of saving time and inconvenience and going with the advice from the tech and getting an AGM battery instead.

Please .... make your decision ONLY on the CCA of what they offer you : it is your Money ! If you settle for a minimal CCA battery, you will get similar results. W/O a very substantial ( not some silly incremental ) increase in Battery Reserves .... you will continue getting the same old results. And , being stuck with a "new" version of the same "old" battery, you will most likely just "kick the can" down the same old ( dead battery ) road. Did that "Road-Side-Assistance" guy come out after you called the Subaru 1-800-Number ???? Might explain why he directed you back to the Source of the poor battery you already have !!!!!!!

 

[MTforester17]

Please .... make your decision ONLY on the CCA of what they offer you : it is your Money !

@MTforester17,
Sorry, the battery in my 2020 forester is same group size 35 as our old 2010 forester and 2006 Impreza.

Thanks for the responses, guys. I did think it was curious that Subaru would try to save fuel by saving a few pounds off the battery. And, for the record, my current plan is to replace the oem battery with an agm, preferably the Odyssey with 820 cca. But, as you said, it's my money, so I'm going to carry a jump starter until I have the bread for the Odyssey. With that battery, Fozzy can sit outside when it's thirty below, and start every time.

 

[hoshie]

For what it’s worth, I talked to a place specializing in batteries today.

the Northstar and odyssey are basically the same. Both premium

they used to carry optima but said they stopped because of the factory changes and inconsistencies in product.

The Northstar fits well (as @ titelies showed).
740 CCA - 4 year warranty (not prorated).
They had nothing but good things to say about it.

the bad part for me is $389. God, being Canadian pizzzzes me off ... from a consumer perspective.

 

[MTforester17]

The Northstar fits well (as @ titelies showed).
740 CCA - 4 year warranty (not prorated).
They had nothing but good things to say about it.

the bad part for me is $389. God, being Canadian pizzzzes me off ... from a consumer perspective.

Autozone has the Odyssey Extreme group 35, 820 cca, 4 yr. warranty, for $295 US which would be $383 Canadian. Looks like around the same price for the Northstar you found.

 

[Marv2]

Thanks for the responses, guys. I did think it was curious that Subaru would try to save fuel by saving a few pounds off the battery. And, for the record, my current plan is to replace the oem battery with an agm, preferably the Odyssey with 820 cca. But, as you said, it's my money, so I'm going to carry a jump starter until I have the bread for the Odyssey. With that battery, Fozzy can sit outside when it's thirty below, and start every time.

INTERESTING ! Those of us with weak batteries usually do NOT have Group-35 batteries until after we throw away the OEM Group-25 Boat-Anchors and DIY Replace the Lawn-Mower-Batteries that we recieved with so much Love ! Wonder why there are some who get Junk-Group-25 Boat-Anchors .... and others who have Group-35's from the Get-Go ????? Are some Dealers shoveling junk into the Vehicles during Dealer-Prep, before Sales ????? Sounds like a real good way to Sabotage an otherwise good vehicle !!!!!

 

[MTforester17]

INTERESTING ! Those of us with weak batteries usually do NOT have Group-35 batteries until after we throw away the OEM Group-25 Boat-Anchors

All I can tell you is that each time I have put 2017 Subaru Forester 2.5L into a search box for battery, group 35 batteries have been displayed -- auto parts stores and battery manufacturer websites.

 

[Yarameme]

Group size 25 has same dimensions as 35. However terminal is reversed. I am pretty sure all the batteries I have replaced for all our Subaru vehicles are group size 35.

 

[Marv2]

OOPPPSSsss ! Got my wires crossed ... again ! I should have been saying GROUP-34 !!!! See indicated Web Site : Group 34 Batteries - Dimensions, Features and Recommendations

 

[foresters23432]

Last year my Subaru battery on my 2017 failed a Mavis load test and of course they wanted to do it for me for nice bucks. It was just out of warranty and these Panasonic garbage were known to fail.
I went to Walmart and got a group 35 640 ampere upgrade on sale, their best with the three year replacement warranty, put it on myself, then sent Subaru Corporate a polite complaint and request for reimbursement. They sent me a great note with full reimbursement check for my battery receipt. And the best pair of free Ray Ban sunglasses for the road I have ever had. Good company.

Thanks again for the tip, I wrote to Sub America and they actually got back to me and said they'd comp my battery costs. Didn't say anything about Ray Bans though

 

[boureesub]

Don't know about Canada but my local Costco carries an Interstate AGM battery in group size 35. That will be my replacement battery when my OEM battery dies. BTW, my OEM battery has never seemed weak but I mostly drive in a warm climate.

I checked on the Interstate group 35 AGM batteries at our local Costco today and was told they don't have it, won't order it, and it's not being made. Odd. Availability must be a regional thing.

 

[Marv2]

I checked on the Interstate group 35 AGM batteries at our local Costco today and was told they don't have it, won't order it, and it's not being made. Odd. Availability must be a regional thing.

Not-Being-Made : Last ditch effort to get you to buy off their shelf ! For your money, and to max-out CCA, your best bet might be a Group 34/34R (post orientation) battery that can push 800+ CCA Group 34 Batteries - Dimensions, Features and Recommendations ; those exra CCA's are what allows the Battery to have longer life in automotive applications. AND ... if you are one of US who have "Battery-Managenment" replenishment-charging or Down-The-Road Charging issues with your Subaru, these larger batteries are the perfect answer: but you may have to add a Battery-Maintainer to your Vehicle's requirements to put a stop to the real culprit to killing Batteries : Sulfation ; which comes from chronic, long-term under-charging in automotive batteries. To read-up on this issue, go to Sulfation and How to Prevent it - Battery University .

 

[boureesub]

Thanks Marv. I’ll look into that when my battery’s time comes. Winter #2 and it’s doin fine. Have a charger/maintainer.

If a group 34 can be made to fit, then so will a 24. Pretty sure someone already fitted one, but not my model year.

 

[Marv2]

Group-34-FIT : If your Battery Tray is the same as mine, it will have about 1/4" spare on the Side, and ~3/4" to spare on the end: everything else will be as-is, except there may be a small, thin "rod" that Subaru added to the metal hold-down bar over the battery, which seems to be for those forsaken folks who can not line up the cross-over bar with the lower main base ..... I just gave it a slight "repositioning" to get it out of the way ... plenty of clearance then !!!!!! Just need to carefully adjust the positions of the Negative Cable & Sensor Wiring to keep it properly spaced & secured.

 

[ForesterBill]

I checked on the Interstate group 35 AGM batteries at our local Costco today and was told they don't have it, won't order it, and it's not being made. Odd. Availability must be a regional thing.

I saw one at my local Costco about 6 months ago - even took a pic of it and I think I posted the pic in a battery thread on this forum.

 

[boureesub]

I believe you. Like I said, it must be a regional thing. The Costco web site still lists them, though doesn't list the Forester (I found the AGM 35 by choosing the Ascent), but it also says to visit your local Costco to order.

 

[ForesterBill]

Next time I'm in my local Costco I'll check and see if they still carry the Interstate AGM 35 here. In the meantime my factory battery is still performing well after 52k miles /2.5 years. However I do periodically put it on a battery charger/maintainer even though I've never experienced any starting weakness.

 

[Marv2]

Assumptions : I notice a lot of guesses about what might cause dead batteries, but actual numerical data is almost impossible to measure; some ideas are very .... interesting, others ... not so much : but for everyone having problems with OEM or other Under-Powered Batteries not having enough CCA capacity to handle small every-day forgetfullness or problems, I'd very seriously recommend that you break the OEM-Equivalent Paradigm and become your own person : go for the "Highest" CCA that you can place inside the Battery Tray, and that is definately what is not OEM Recommended ! Go to whoever you "trust" and have your Battery temporarily removed from your Vehicle; then measure the dimensions for the bottom of the Battery-Holder-Tray (remember that all batteries are somewhat rounded at the Bottom, so they will fit in that last 1/4" { ~1/2-CM} that you think that you will need to give up on !). Then go to the Web-Site : BCI Battery Group Size Chart and find a couple battery sizes ( aka, "Group" ) that will Physically fit in your Model, noting that some Groups come in Normal Post Configuration, and others come in "R" Sub-Groups ( Reversed Polarity Posts ). Make a sketch of your in-place Battery Positioning & Post Polarity when you go shopping, maybe taking your Helping-Hand Person with you. Your Goal should be to get an 800~900-CCA Replacement Battery. Also, you can verify how much taller a new Battery can safely be by placing a small stack of wooden blocks, or even Phone-Books on top of the existing battery, and gently closing the Hood on top of the Stack to see how tall a Stack can tolerate the closed Hood.... then reduce the Height-Number by about ~1" {or about 2-3-CM }. You should find that the Battery Case can very safely hold a new Battery at least 2" Taller ( ~5-CM ) and still safely clear the Hood; also, the Battery Clamp Hold-Down Srews ("bolts" ) are VERY LONG ! So they will also accomidate a taller battery by the same amounts that you might measure. After getting a 2X-3X Higher CCA Battery, most of your Dead-Battery-Issues should magically disappear !!!!!

Excess Current Draw !
New Discovery !
While researching the EVAP-System, I found a Subaru Service Manual Document that details the Test-Cycle(s) for the EVAP Tests : make sure that you recognize that I am posting this as a Plural Subject !!!

According to what I read, buried deep in the Service Manual, was a Test-Cycle that repeats itself over-and-over-and-over !!!! Some parts of the Test-Cycle-Diagram seems to indicate that the major part of the Test (running the 12-Volt Air-Pump-Motor ( a substantial battery load !!!) may repeat about every (9-!) nine-hours, as long as the vehicle sits !!!! That is (as I understand it ) until the Battery is DEAD !!!!!

 

[JessD]

I believe you. Like I said, it must be a regional thing. The Costco web site still lists them, though doesn't list the Forester (I found the AGM 35 by choosing the Ascent), but it also says to visit your local Costco to order.

I checked both my local Costco's for the group 35 AGM, the first one told me they were backordered and wouldn't bother trying to order them. The other one also did not have them but told me that the Interstate AGM batteries in general were mostly all backordered, but that he'd try to order one if I decided to go for it. All in all, I was told to not expect any new AGM batteries at Costco for a few months.

 

[boureesub]

According to what I read, buried deep in the Service Manual, was a Test-Cycle that repeats itself over-and-over-and-over

Can you share this info? Which year is the manual, a screen shot of the page with the info, etc?

The 2019 shop manuals, tech reference booklets, TSB's, etc that I have are silent on the test being repetitive. The only explicit mention of the test occurring with the car off, is as part of a cautionary note when measuring dark current. It notes that the ELCM (evaporative leak check module) might run after a period of 20 minutes or so. See below.