Your Subaru Forester is a boxer-engine all-wheel-drive machine, and that combination asks a lot of a battery. Cold mornings, the constant draw from heated seats, the EyeSight cameras, and frequent short trips all chip away at battery life faster than many owners expect. Most Foresters from 2009 onward use a Group 35 battery, while some earlier models run a Group 25, so getting the fitment right matters as much as the brand. we researched and researched the top replacement batteries that actually drop into a Forester engine bay without modification.
Below are seven batteries that match Forester terminal layout and hold-down requirements, ranked by cold cranking power, real-world lifespan, and how well they cope with the stop-start short-trip driving that Foresters often see. We have flagged honest weaknesses on every pick so you know exactly what you are buying before you commit.
| Photo | Product | Score | Buy |
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Optima Batteries RedTop 35 Best Overall Group 35, AGM spiral-cell, 720 CCA, 44Ah reserve |
9.5 | 🛒 Check Price |
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Odyssey 35-PC1400T Performance Series Longest Lifespan Group 35, AGM TPPL, 850 CCA, up to 10 year design life |
9.3 | 🛒 Check Price |
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DieHard Platinum AGM Group 35 Best Cold Weather Group 35, AGM, 650 CCA, enhanced reserve capacity |
9.1 | 🛒 Check Price |
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ACDelco 35AGM Professional AGM Best Value AGM Group 35, AGM, 650 CCA, high cycling durability |
8.9 | 🛒 Check Price |
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EverStart Maxx Group 35N Best Budget Pick Group 35N, lead-acid flooded, 640 CCA, strong reserve |
8.6 | 🛒 Check Price |
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Bosch S6 AGM Group 35 Best for Start-Stop Group 35, AGM, 680 CCA, optimized for high electrical demand |
8.4 | 🛒 Check Price |
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NORTHSTAR NSB-AGM35 Pure Lead Best Deep Cycle Group 35, TPPL AGM, 880 CCA, very high reserve capacity |
8.2 | 🛒 Check Price |
1. Optima Batteries RedTop 35: Best Overall
The Optima RedTop 35 is the pick we trust most for a Subaru Forester because it matches Group 35 fitment exactly and delivers 720 CCA, which is more than enough to spin a cold boxer engine on a frosty morning. The spiral-wound AGM cells shrug off the constant vibration that comes with washboard forest roads and trail use, and because it is fully sealed you never deal with terminal corrosion or acid weeping. For a Forester that mostly does starting duty rather than running winches or big audio, this battery is close to ideal.
The honest weakness is reserve capacity. The RedTop is engineered to deliver a hard burst of starting current, not to sit and power accessories with the engine off, so its 44Ah reserve trails some flooded options. If you frequently leave the EyeSight system, lights, or a fridge running without the engine on, a YellowTop or a higher reserve flooded battery suits you better. As a pure cranking battery for a daily Forester, though, it is hard to beat.
- SpiralCell AGM design resists vibration from gravel and trail driving
- 720 cold cranking amps for confident sub-zero starts
- Sealed and spill-proof, mounts in nearly any orientation
Pros: Outstanding cold weather starting power; Extremely vibration resistant for off-road Foresters; Long service life when not deeply cycled
Cons: Reserve capacity is lower than some flooded rivals; Heavier than the factory battery
2. Odyssey 35-PC1400T Performance Series: Longest Lifespan
The Odyssey 35-PC1400T uses Thin Plate Pure Lead AGM construction, and that gives it both brutal cranking power and genuine deep-cycle tolerance. With 850 CCA it overdelivers for a Forester, which means it barely breaks a sweat starting the engine even after the car has sat in the cold for days. The standout reason to choose it is longevity. Odyssey rates this series for a much longer design life and far more deep cycles than a typical flooded battery, so the value comes from how rarely you replace it.
The catch is that to get that full lifespan you really should keep it properly charged, ideally with a quality AGM-capable charger or maintainer if the Forester sits unused. Chronic undercharging from lots of short trips can shorten any AGM battery, and this one rewards owners who look after it. It is also heavy and the upfront commitment is real, so it suits owners planning to keep their Forester for many years rather than flipping it soon.
- Thin Plate Pure Lead chemistry for huge cranking output
- Rated for 400 charge cycles to 80 percent depth
- Tolerates extreme heat and cold without capacity loss
Pros: Massive 850 CCA for the hardest cold starts; Very long design life reduces replacement frequency; Deep cycle ability handles accessory loads
Cons: Premium battery that demands a proper charger; On the heavy side for the group size
3. DieHard Platinum AGM Group 35: Best Cold Weather
The DieHard Platinum AGM in Group 35 is a balanced choice for Forester owners who live where winter actually bites. Its AGM internals keep starting voltage strong when temperatures drop, and the reserve capacity is noticeably better than a pure cranking battery, which helps Foresters that do a lot of stop-start city driving with the EyeSight cameras, climate fan, and heated seats all pulling current. For most owners it hits the sweet spot between cold starting and everyday accessory support.
The honest downside is that 650 CCA, while perfectly adequate for the Forester, is lower than the Odyssey or Optima, so if you park outdoors in genuinely extreme cold you give up a little headroom. Availability has also shifted as the DieHard brand changed hands, so stock can be patchy depending on where you shop. When you can get it, it is a dependable, low-fuss AGM that fits the Forester without drama.
- AGM build delivers strong starts in deep freeze conditions
- Higher reserve capacity than standard cranking batteries
- Maintenance free and fully sealed against leaks
Pros: Reliable starting in harsh winter climates; Good reserve for accessory and short-trip use; No maintenance or watering needed
Cons: Availability can vary by region; Not the highest CCA in this list
4. ACDelco 35AGM Professional AGM: Best Value AGM
The ACDelco 35AGM Professional brings genuine AGM benefits to Forester owners who want the corrosion resistance, vibration tolerance, and cycling durability of absorbed glass mat without reaching for the most expensive name on the shelf. The calcium-silver alloy plates and envelope separators help it survive the repeated partial discharges that short-trip Subaru driving inflicts, and as a sealed unit it stays clean in the engine bay. For drivers who recharge through a charger occasionally, it is a smart, durable choice.
The weakness is straightforward. At 650 CCA it sits in the middle of this group, so it is not the battery to pick if maximum cold-start margin is your top priority. It is also heavier than the flooded batteries here. But as a well-built AGM that fits the Forester and offers strong long-term durability for the value, the ACDelco earns its place and rarely disappoints.
- Calcium-silver alloy plates for better life and performance
- Durable envelope separator improves acid circulation
- Sealed AGM design with strong vibration resistance
Pros: Solid AGM performance without a premium badge; Good cycle life for short-trip Foresters; Trusted OE-level brand quality
Cons: CCA is mid-pack for the group; Heavier than a basic flooded unit
5. EverStart Maxx Group 35N: Best Budget Pick
The EverStart Maxx in Group 35N is the practical, no-nonsense pick for Forester owners who want a dependable replacement without overthinking it. It delivers 640 CCA and a healthy reserve, which covers the starting and accessory demands of a typical Forester comfortably. Its biggest practical strength is availability. You can find one quickly almost anywhere, which matters a great deal if your battery dies far from home and you need a Group 35 fitment that same day.
Being a flooded lead-acid battery, its honest weakness is lifespan and ruggedness compared to the AGM options above. It will not match the Odyssey or Optima for years of service or for surviving heavy trail vibration, and deep discharges hurt it more. For an owner who drives mostly on pavement and values a straightforward, widely stocked replacement, though, it offers genuinely good value and reliable everyday performance.
- Wide availability makes replacement easy on a road trip
- Solid reserve capacity for accessory loads
- Proven flooded chemistry at an accessible value
Pros: Easy to find and quick to swap in; Good cold cranking for the value; Decent reserve minutes for short trips
Cons: Shorter expected lifespan than AGM rivals; Flooded design less vibration tolerant off-road
6. Bosch S6 AGM Group 35: Best for Start-Stop
The Bosch S6 AGM is built for vehicles with heavy electrical demand, which makes it a natural fit for a modern Forester loaded with EyeSight cameras, driver assistance electronics, heated seats, and infotainment. Its AGM design tolerates the frequent partial charge and discharge cycles that come from running all that gear on short urban drives, and with 680 CCA it has plenty of muscle to start the boxer engine in the cold. For tech-heavy trims, it manages the electrical load gracefully.
The honest drawback is sourcing. Bosch automotive batteries are common in Europe but can be less consistently stocked in North America, so finding the exact Group 35 fitment may take a little searching depending on your region. If you can get it, you are getting a well-engineered AGM that suits electronics-rich Foresters, but the availability hurdle is the reason it sits a little lower in our ranking despite its quality.
- AGM construction tuned for high-cycle electrical loads
- 680 CCA for confident cold starting
- Sealed, maintenance-free and corrosion resistant
Pros: Handles heavy accessory and electronics demand well; Strong cold cranking output; Reliable European-engineered build quality
Cons: Can be harder to source than mainstream brands; Premium positioning for a Group 35
7. NORTHSTAR NSB-AGM35 Pure Lead: Best Deep Cycle
The NORTHSTAR NSB-AGM35 is a Thin Plate Pure Lead AGM aimed at Forester owners who treat the vehicle as a basecamp. With a high reserve capacity and a strong cranking rating, it does double duty, powering camping gear, fridges, lights, and recovery equipment when parked, then still starting the engine without hesitation. For overlanders and owners who have added electrical accessories, this is the battery that handles repeated deep draws without dying early.
That capability comes with honest tradeoffs. It is one of the heaviest batteries in this group, and it is a meaningful investment that most stock Foresters simply do not need. If you only ever start the engine and run factory accessories, you are paying for headroom you will not use. But for a built-out, accessory-rich Forester that genuinely cycles its battery, the NORTHSTAR delivers a level of resilience the simpler options here cannot match.
- Pure lead TPPL chemistry for extreme cranking and cycling
- Very high reserve capacity for accessory-heavy builds
- Low self-discharge for vehicles that sit between trips
Pros: Exceptional cranking and deep-cycle ability together; High reserve suits camping and accessory loads; Holds charge well during long storage
Cons: Among the heaviest options here; A serious investment for a stock Forester
Frequently Asked Questions
What size battery does a Subaru Forester take?
Most Subaru Foresters from roughly 2009 onward use a Group 35 battery, which is the size the majority of picks on this list match. Some earlier Foresters and a few specific configurations use a Group 25, and certain models accept a Group 35N variant. Always confirm by checking the dimensions of your current battery and the terminal layout, or by entering your exact model year into the fitment checker before you buy. Getting the group size and terminal orientation right is just as important as choosing a good brand.
Should I get an AGM or a standard flooded battery for my Forester?
For most Forester owners, AGM is the better long-term choice. AGM batteries handle the frequent short trips and heavy accessory loads of a modern Subaru far better than flooded batteries, they resist vibration from rough roads, and they last longer on average. A flooded battery like the EverStart Maxx is still a perfectly reliable and easy-to-find option if you drive mostly on pavement and want a simple replacement. If your Forester sees cold winters, trail use, or lots of electronics, lean AGM.
How many cold cranking amps does a Forester need?
A Subaru Forester boxer engine starts comfortably with a battery in the 600 to 720 CCA range, and every battery on this list meets or exceeds that. More cold cranking amps gives you extra starting margin in very cold climates, which is why options like the Odyssey at 850 CCA and the NORTHSTAR at 880 CCA appeal to owners in harsh winter areas. You do not need the highest CCA on the market, but matching or modestly exceeding your factory rating is the safe approach.
Why does my Forester battery keep dying so quickly?
Frequent short trips are the most common culprit. A Forester loaded with EyeSight cameras, heated seats, and infotainment draws a lot of current at startup, and short drives do not give the alternator enough time to fully recharge the battery. Over time this leaves the battery chronically undercharged, which kills it early. An AGM battery tolerates this pattern better, and using a quality battery maintainer when the car sits can dramatically extend life. It is also worth having the alternator and parasitic draw checked if the problem persists.
Can I replace the Forester battery myself?
Yes, replacing a Forester battery is a straightforward job for most owners. Disconnect the negative terminal first, then the positive, release the hold-down bracket, and lift the old battery out, keeping it level. Set the new battery in place, secure the bracket, then reconnect positive first and negative last. Because modern Foresters have memory settings and driver assistance systems, you may want to use a memory saver during the swap so you do not lose presets. Always wear gloves and eye protection, and recycle the old battery.
Our Verdict
For the vast majority of Subaru Forester owners, the Optima RedTop 35 is our top pick thanks to its exact Group 35 fitment, strong 720 CCA cold starting, and excellent vibration resistance for trail-driven Subarus. If you keep your Forester for the long haul and want maximum lifespan, the Odyssey 35-PC1400T is the runner up, trading a little extra weight and a higher commitment for huge cranking power and a much longer design life. Match the group size to your exact model year, lean AGM if you face cold winters or heavy electronics, and you will not be stranded on a frosty morning.
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