[Fibber2]

so preemptively replaced it with an AGM. Located in TX so high heat.

A 2018 (SJ), so not applicable recommendation for this thread (2019+).

 

[shihfa]

Hello,

I need to replace the battery on a Subaru Forester Sport. Does anyone know if it is better to replace the battery with an EFB or AGM?

Thank you and Regards,

 

[ForesterBill]

I would suggest you start reading this thread with post #87.

 

[auntiesuebee]

Hello,

I need to replace the battery on a Subaru Forester Sport. Does anyone know if it is better to replace the battery with an EFB or AGM?

Thank you and Regards,

It came with an EFB, you should replace it with another EFB. Depending on your style of driving, an AGM my or may not be up to the task. Subaru's charging programming doesn't always play well with an AGM in stop/start equipped vehicles.

 

[fr0sty]

Has anyone ever gone and got a battery replaced through the class action lawsuit and if so, what was the process/experience? The battery in my 2020 Forester with AS/S was definitely getting weak during this past winter in Boston. Had 1 or 2 times where it couldn't start back up and I had to shift the car into park, shut it off, and then restart the car. I also have a Viofo dashcam hardwired to have parking mode and not sure if that would exclude me from this class action.

 

[cherrytrek]

I thought I'd add my dad's experience with his 2019 Forester. His original battery recently tested weak at his last service visit to the dealer and they quoted over $400 to replace the battery with the updated 640 CCA OEM battery (original was 620 CCA) and replace the battery tray with a larger one to accommodate it. His original battery lasted about 4.5 years and never failed to start. His Forester only has just over 20k miles. He disables auto start/stop sometimes, but sometimes he leaves it on. He got the battery replaced with an Optima Red top at O'reilly. Saved around $150 over the dealer's quote. It was listed in their system as compatible with a 2019 Forester. The battery included a height adapter/riser for the Optima to sit on because it is shorter in height than a typical group 35. From the specs, it exceed the CCA rating, but has a lower Ah capacity. I need more specs on the OEM battery to compare reserve capacity. We'll see how it performs and lasts.

https://www.oreillyauto.com/detail/c/redtop/optima-red-group-size-35-top-post-battery/obt2/red35/v/a/146665/automotive-suv-2019-subaru-forester?q=optima+red+group+35&pos=0

OEM (read from the label and markings)

• Q85
• 620 Cold Cranking Amps
• 20HR (not sure what spec this is)
• 62 Ah capacity
• D23 (JIS)

Optima Red

• Group 35
• 720 Cold Cranking Amps
• 90 minute reserve capacity
• 44 Ah capacity

 

[Fibber2]

• 20HR (not sure what spec this is)
• 62 Ah capacity

The 20 hour test is a way of determining battery energy capacity. A constant draw on the battery for 20 hours until the voltage drops below 10.5 volts (IIRC). So a 62 Ah battery can deliver 3.1 amps constant draw.

With a rating of 44 Ah, that red top can only deliver 2.2 amps continuous. That's a bit on the light side for a A-S/S application.

In my view, the battery you went with is a 'sprinter' and not a marathon runner. A good starting battery for conventional use, but not as well suited for the constant demands of an A-S/S system and a 'smart alternator' that seems to prefer to keep the battery in not much better than a moderate state of charge. The lower reserve and Ah rating might not deliver long term.

The real issue is that EFB construction batteries are not a popular item in the US, so finding a good replacement at a reasonable price isn't easy. AGM batteries have become the go-to replacement, but as we have learned from a battery expert I brought to the table in another thread, they aren't an ideal replacement for a charging system set up for a EFB battery.

 

[cherrytrek]

@Fibber2,
Thank you. I agree with your summary of the Optima Red for this application. He chose it mostly because it was listed as compatible and was available locally. I probably would have chosen something different if I knew what I know now. It "works", but doesn't meet all the same specs as the factory battery. I'm curious how adaptable the battery management system is to a different battery and if he will notice any difference. I don't expect it be able to run the accessories with engine off as long as the factory battery could. I just hope that it doesn't ever fail to restart after an "auto stop".

The battery replacement cost was quite the shock compared to the last car battery we bought, which was $110 for a 2011 Outback. Interestingly, our Ascent only has 530 CCA standard lead-acid battery because it doesn't have Auto Start-Stop. Should still be cheap to replacement when the time comes.

It's troublesome that there are no reasonable aftermarket EFBs available by now. Subaru is not the only one using EFBs. I know Toyota Hybrids, some Mazda models, and others use them as well. I've seen it stated that AGM batteries are superior to EFBs and OEMs are too cheap to spec an AGM, but that doesn't appear to be true. EFBs can be superior to AGMs in certain applications. TBH, I'm impressed with what the OEM EFB is capable of. I hope there are more options by the time my Crosstrek needs its battery replaced. It has Auto Start-Stop and has the same OEM battery that the 2019 Forester came with. I'm not an Auto Start-Stop hater. It's saved over 14 hours of idle time over 11k miles for me. It seems like the battery is the primary increased maintenance cost for Auto Start-Stop.

 

[boureesub]

When this thread began back in 2020, the documentation available on battery replacements for the 2019 Forester pointed towards EFB or AGM. More recently, it has come to light that there may be some risks with AGM in a start/stop application (2019+ for Forester) particularly in a hot climate. We’re talking reduced battery life. I’ll try to find the thread discussing this and include it here.

edit: this thread. The link picks up in the middle, so you might need to go back a bit to get everything in context. In particular, read the posts from @Fibber2.

(All Years) - 2014+ - Battery specs and replacement...

Hello All, This is a pro-active request, and if this has been covered elsewhere, please provide the link to me. With the many Forester battery issues, I'm thinking of installing a higher capacity battery in my 2020 Forester Touring, and would like to get some recommendations on the same. And...

www.subaruforester.org

No disrespect to auto parts stores, but what they consider compatible means the battery will fit, and not much else.

 

[Oldguy2]

I know this is an old thread, but just for giggles and grins I asked the parts department what it cost to replace the Q85 battery on my 2021 Forester when I was at the Subaru dealer a couple of days ago. Interestingly they told me there is a new EFB battery (SOA821B900) that replaces the PB001993 that came from the factory with my car. And since it is physically a different size, I would also need to buy a new battery pan, battery cover, as well as some grommet sheet to install it. I was quoted $353 for the battery and another $50 for the various parts. When I went home a looked up the new part number on the dealer's web site, they showed the price at $306. Subaru direct wholesale wanted $249. Good thing I didn't actually need to buy one right now.

And I thought $200 for an AGM group 35 size battery at Sam's Club was expensive.

 

[Old Man]

It came with an EFB, you should replace it with another EFB. Depending on your style of driving, an AGM my or may not be up to the task. Subaru's charging programming doesn't always play well with an AGM in stop/start equipped vehicles.

Has not been an issue with my 2020. AGM has started car quicker (faster turnover) and has sat at Dulles for 9 days and acted perfectly. I put a trickle charger on it right after I drove it 120 miles with lights on (at night) and the charger showed full charge. I would not hesitate to get an AGM ($206 at Costco).

 

[Oldguy2]

The plot thickens. Wish I saw this post first. 19 battery replacement I was quoted the very same part numbers for my 21 Forester as Fibber2 detailed out in this post as part of the lawsuit settlement. Show have known.

 

[auntiesuebee]

Has not been an issue with my 2020. AGM has started car quicker (faster turnover) and has sat at Dulles for 9 days and acted perfectly. I put a trickle charger on it right after I drove it 120 miles with lights on (at night) and the charger showed full charge. I would not hesitate to get an AGM ($206 at Costco).

It works for your driving style. An AGM in an AS/S equipped Subaru does not work for everyone.

The new EFB may be just as good as any AGM, time will tell.

 

[SubaruMan_go]

---

 

[bman400]

Has not been an issue with my 2020. AGM has started car quicker (faster turnover) and has sat at Dulles for 9 days and acted perfectly. I put a trickle charger on it right after I drove it 120 miles with lights on (at night) and the charger showed full charge. I would not hesitate to get an AGM ($206 at Costco).

Beware the slightly higher charging voltage required for AGM batteries, ie they need 14.8v from the alternator to keep them happy.....On my 2001 there is a ALT-MOD that can be done to trick the alternator to supply this slightly higher voltage, on your newer model, I am not certain that's possible with the battery/voltage sensor attached to the battery terminal. EFB are far more common in Europe vs AGM being more common in the US/Canada.

Only time will tell if EFB prove to perform as well or better than the AGM.

 

[supasta]

I replaced the battery yesterday. Group 35 AGM Interstate from Costco.

I had yet another complete discharge while camping this past week. Fortunately the campground host had a jump box.

 

[ForesterBill]

@supasta How long ago did you purchase the group 35 Interstate AGM from Costco? Reason I ask is because I had Costco order that same battery last week for my wife's 2019 Crosstrek. This morning I received a voicemail from Costco stating that the group 35 AGM battery "is not going to be orderable for a while because the plant burned down that was making them".

 

[supasta]

@ForesterBill

Purchased and installed yesterday, 8/27.

Only 1 Costco location in Colorado had them at all. It was about 15-minutes away from me. 6 on the shelf. Manufactured 8/23 - all 6 with the same manufacture date.

The Costco closest to me said that he would be happy to order the battery, and that he could, but then offered that the store 15-minutes away had 6. I opted to go that route so that I wasn't risking being stranded with a dead battery in the meantime.

Of note, he did also mention that the nearest store from there was in AZ. He didn't state which city, he was clearly joking around.

 

[MidAtlanticGuy]

Hi folks,

I have a 3-year old OEM battery in my 2018 Forester 2.0 XT, and I'd like to proactively replace the battery with a new one, before Winter sets in (I'm in the Mid-Atlantic, so it can get up to 100 degrees in Summer, and fairly cold in Winter, around 25 degrees). I do park the car indoors year-round.

Can you recommend a specific super-good battery that will fit in my Subie without any modifications, and one that I can buy locally? (i.e., not have to order through the mail)

I don't mind spending good coin on a battery - in fact I'd rather buy a really good battery (within reason of course). I also don't belong to any wholesale clubs so buying from them wouldn't work.

What do you think? Any recommendations for 2023?

Also, what are good tips for buying a battery? (for example, I hear the battery should be pretty "fresh", as in made in the last 6 months, etc.)

Thanks!!

 

[bman400]

@MidAtlanticGuy Does your vehicle have AS/S - auto stop/start? That technology limits your choices if you want to retain warranty from Subaru.