10 Best Battery Size Options for 2020 Subaru Forester in 2026: Smart Fitment Picks for Key Fobs and Main Batteries

If you’re shopping for a battery size for 2020 Subaru Forester models, the main challenge is knowing whether you need a key fob cell or the vehicle’s starter battery.

This roundup highlights the most relevant fitment options so you can buy with confidence and avoid common sizing mistakes.

Best 10 Battery Size for 2020 Subaru Forester Picks for 2026

Key Fob Battery Pick – Subaru Smart Fob CR2032 2-Pack

If you’re looking up the battery size for 2020 Subaru Forester key fobs, this CR2032 option is the standard replacement for compatible Subaru smart remotes. This pack is aimed at owners who want a quick DIY fix without booking a service visit, and it includes pry tools plus a video guide to help with installation.

Best For: Subaru smart-fob owners who need a simple CR2032 replacement and want to do the swap themselves.

Pros:

• Includes two CR2032 batteries plus opening/pry tools.
• Compatible with 2015-2025 Subaru smart fobs, including Forester listings.
• No reprogramming required after installation.
• Step-by-step video guidance is provided.

Cons:

• Not compatible with standard Subaru keys that have the blade sticking out.
• Fitment should still be confirmed before ordering.

For a key fob battery swap, this is a practical low-cost choice if your 2020 Forester uses the compatible smart remote style. The included tools and instructions make it easier to handle at home.

AGM Car Battery Match – Group 35 12V 55Ah Replacement

If you’re searching for the battery size for 2020 Subaru Forester as a full vehicle battery, this Group 35 AGM replacement is the type to compare against. It’s listed as a 12V, 55Ah battery for Subaru Forester 19-23 applications, making it a straightforward fitment-focused option for owners who need a replacement battery rather than a fob battery.

Best For: Forester drivers needing a Group 35 AGM replacement battery for compatible 2019-2023 models.

Pros:

• Listed as a Group 35, 12V, 55Ah AGM battery.
• Compatible with Subaru Forester 19-23 applications.
• Maintenance-free AGM design helps prevent spills and leaks.
• Designed for durability, vibration resistance, and cold-weather starting.

Cons:

• Fitment is specific to compatible Forester model years.
• Bullets mention motorcycles and powersports generally, so confirm your vehicle application carefully.

This is the closer match if you need an under-hood replacement battery, not a key fob cell. The Group 35 size, 55Ah rating, and sealed AGM construction make it a solid spec-based comparison point.

Smart Remote Battery Kit – Subaru CR2032 2-Pack

When you’re checking the battery size for 2020 Subaru Forester smart keys, this pack is another CR2032 replacement built for compatible Subaru smart fobs. It’s designed for owners who want a fast self-install option and prefer to avoid dealer service charges, with a fitment guide available in the product images.

Best For: Subaru smart-fob owners who want a quick CR2032 swap with fitment guidance.

Pros:

• Includes two original premium CR2032 3V batteries.
• Compatible with 2015-2025 Subaru smart fobs.
• No programming required after battery replacement.
• Fitment guide and easy DIY instructions are provided.

Cons:

• Not for standard Subaru keys with the blade attached.
• Does not include the actual key fob.

This option is well suited to a simple, low-hassle fob battery change. If your Forester uses the compatible smart remote style, the CR2032 size and included guidance make it easy to handle at home.

Vehicle Battery Replacement – Subaru Forester Group 35 AGM

If you need the battery size for 2020 Subaru Forester as a full replacement battery, this Mighty Max unit is a Group 35 12V AGM model with a 55Ah rating and 650 CCA. It’s positioned as a direct vehicle-specific fit for Subaru Forester 19-23, so it’s the kind of listing to review when comparing under-hood battery specs.

Best For: Drivers who want a spec-matched Group 35 AGM replacement for compatible Forester models.

Pros:

• Group 35, 12V, 55Ah battery with 650 CCA.
• Compatible with Subaru Forester 19-23.
• 100-minute reserve capacity supports longer runtime.
• Sealed AGM design is spill-proof and maintenance-friendly.

Cons:

• Vehicle-specific fit means you should confirm your exact model year and setup.
• Wire harness and mounting accessories are not included.
• Polarity and dimensions should be checked before installation.

For shoppers comparing the battery size for 2020 Subaru Forester, this is a strong Group 35 reference with clear electrical specs. The AGM construction and included mounting screws add convenience, but fitment checks still matter.

Key Fob Battery Replacement – CR1620 Key Fob Battery for Subaru 2010-2020

If you’re checking the battery size for 2020 Subaru Forester key fobs, this replacement uses a CR1620 coin cell for compatible 3- or 4-button head key fobs. It’s a straightforward option if you want to replace the remote battery yourself instead of paying dealer service charges.

Best For: Subaru owners with compatible head key fobs who want an easy DIY CR1620 replacement.

Pros:

• Includes two CR1620 batteries, so you have a spare on hand.
• Comes with opening/pry tools and an installation video for easier replacement.
• OEM-style batteries are listed as the same type used in original Subaru head fobs.
• No reprogramming is needed after battery replacement, per the product notes.

Cons:

• Only fits compatible Subaru head fobs, not every key style.
• Keyless entry remote fob itself is not included.

This is a practical pick if your Forester uses the compatible Subaru head fob style and you want a simple battery swap. It’s aimed at convenience, with the tool and video support making the process easier.

Starting Battery Pick – Group 35 AGM Battery for Forester

If you need the main battery size for 2020 Subaru Forester-style fitment, this Group 35 AGM replacement is built around 12V, 55Ah, and 650 CCA. It’s a vehicle-specific battery aimed at strong starting power and steady performance in harsh conditions.

Best For: Drivers who want a Group 35 AGM replacement with solid cold-cranking power and easy vehicle fitment.

Pros:

• 12V, 55Ah, 650 CCA spec supports strong starting power.
• AGM sealed design is spill-proof and maintenance-friendly.
• 100-minute reserve capacity adds useful run-time support.
• Includes mounting screws for installation.

Cons:

• Wire harness and mounting accessories are not included.
• Designed for Group 35 fitment, so compatibility must match your vehicle’s battery tray.

This battery is a solid match if your Forester uses Group 35 and you want a sealed AGM option with dependable starting specs. The dimensions and terminal layout are clearly stated, which helps when comparing fit before buying.

Best for Comfort – Group 35 AGM Battery for Crosstrek 16-20

For shoppers comparing the battery size for 2020 Subaru Forester against similar Subaru applications, this Mighty Max Group 35 AGM battery offers the same 12V, 55Ah, 650 CCA format. It’s built for reliable starting power, sealed construction, and vehicle-specific installation support.

Best For: Subaru drivers who need a Group 35 AGM battery with strong starting specs and a sealed design.

Pros:

• 12V, 55Ah, 650 CCA output is suited for steady starts.
• AGM construction is sealed and spill-proof.
• 100-minute reserve capacity supports longer runtime.
• Includes mounting screws for easier installation.

Cons:

• Wire harness and mounting accessories are not included.
• Listed for Crosstrek 16-20 compatibility, so fit should be verified for your exact vehicle.

This is a straightforward battery option if your Subaru calls for Group 35 and you want a durable AGM replacement. The product notes emphasize shock and vibration resistance, making it a sensible everyday fitment choice.

AGM Replacement Pick – Mighty Max MM-G35 Group Size 35

If you’re comparing battery size for 2020 Subaru Forester use, this Mighty Max Group Size 35 battery is a straightforward AGM option built for dependable starting power. It’s rated at 12V, 55Ah, and 650 CCA, with a sealed design that aims to handle daily driving and changing weather without the mess of a traditional flooded battery.

Best For: Drivers who want a Group 35 AGM replacement with solid cold-start specs and simple fitment support.

Pros:

• 12V, 55Ah, 650 CCA setup provides strong starting power.
• AGM design is sealed, spill-proof, and vibration resistant.
• 100-minute reserve capacity supports longer runtime.
• Includes mounting screws for easier installation.

Cons:

• Wire harness and mounting accessories are not included.
• Fitment is specific, so verifying Group Size 35 is still important.

Overall, this is a practical replacement choice if your Forester calls for a Group 35 battery and you want a durable AGM build with a balanced mix of starting power and reserve capacity. The right-side positive terminal and listed dimensions help narrow compatibility before you buy.

Simple OEM-Style Swap – Mighty Max MM-G35 Group Size 35

For shoppers researching battery size for 2020 Subaru Forester use, this Mighty Max Group Size 35 battery offers the same 12V AGM formula in a vehicle-specific fit format. It combines 55Ah capacity with 650 CCA and a sealed spill-proof build, making it a sensible choice when you want reliable starts and low-maintenance operation.

Best For: Drivers looking for a durable Group 35 AGM battery with easy-to-understand specs and a simple replacement path.

Pros:

• 12V, 55Ah, 650 CCA specification supports steady starting power.
• AGM construction is sealed and spill-proof.
• 100-minute reserve capacity adds useful runtime.
• Dimensions and right-side positive terminal are clearly listed.

Cons:

• Not bundled with wire harness or mounting accessories.
• Vehicle-specific fit still requires checking your exact battery tray needs.

This version is best viewed as a clean replacement option for drivers who want the same core performance profile in a Group 35 size. Its rugged, vibration-resistant construction and included mounting screws make it easy to evaluate as a practical OEM-style swap.

Durable Daily-Driver Choice – Mighty Max MM-G35 Group Size 35

If you’re sorting out battery size for 2020 Subaru Forester and want a Group 35 option with clear performance ratings, this Mighty Max battery is built around the same 12V, 55Ah, 650 CCA AGM formula. It’s designed for steady starts, spill-proof operation, and broader temperature resilience, which makes it a practical pick for everyday driving.

Best For: Buyers who want a dependable Group 35 AGM battery with strong starting specs and rugged construction.

Pros:

• 12V, 55Ah, 650 CCA rating delivers reliable starting power.
• AGM build is sealed, spill-proof, and deep-discharge tolerant.
• 100-minute reserve capacity supports longer use between charges.
• Rugged construction is made to resist shock and vibration.

Cons:

• Mounting accessories and wire harness are not included.
• Compatibility should still be confirmed against your exact Group 35 needs.

As a replacement battery, this model stands out for combining easy-to-read specs with the durable traits many Forester owners want in daily use. If your vehicle calls for Group 35, the listed size, terminal layout, and AGM design make it an easy battery to compare.

How We Picked the Best Battery Size for 2020 Subaru Forester

We focused on products that match the most common battery needs for Subaru owners: smart key fob cells and the main 12V AGM replacement battery. Fitment, battery type, and compatibility notes mattered most, especially for buyers comparing the Battery Size for 2020 Subaru Forester against related Forester model years.

We also prioritized listings with clear size references, such as Group 35 for the main battery and CR-series coin cells for key fobs, since those are the details that prevent returns and installation issues.

Quick Comparison

For the vehicle itself, the key question is typically a Group 35 AGM battery with the correct cold-cranking amps and reserve capacity. For the remote, the decision is usually between a CR2032 or CR1620 depending on the exact fob style.

That means the Battery Size for 2020 Subaru Forester shoppers should first identify whether they are replacing a start battery or a remote battery, then confirm the exact fitment before checkout.

Key Buying Factors for Battery Size for 2020 Subaru Forester

Main Battery Vs. Key Fob Battery

The main battery powers the engine and electrical systems, while the key fob battery powers remote lock/unlock functions. These are not interchangeable, and they use very different sizes.

Group Size and Chemistry

For the main battery, look for Group 35 in AGM format when comparing options for a 2020 Forester. AGM batteries are commonly chosen for durability and strong performance in daily driving and cold weather.

Cold-Cranking Amps and Reserve Capacity

If you drive in lower temperatures or make frequent short trips, CCA and RC matter as much as physical size. Higher CCA can help with reliable starting, while reserve capacity supports accessory loads and short-term backup power.

Exact Fob Fitment

Subaru key fobs may use different coin cells depending on the remote design. Before ordering, match the battery number printed on the old cell or verify by fob style rather than assuming every Subaru remote uses the same size.

Who Should Buy Which Battery Size for 2020 Subaru Forester?

If you need the main battery for a 2020 Forester, choose a Group 35 AGM unit with the correct performance ratings and vehicle fitment confirmation. If you only need a dead remote fixed, a CR2032 or CR1620-style replacement is the more likely answer.

Drivers who want the safest purchase should compare the exact model year, engine configuration, and remote style before ordering. That simple check is the easiest way to get the right Battery Size for 2020 Subaru Forester ownership without wasting time on returns.