Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
Your WRX battery has to fit before it can perform. Get the group size wrong and the battery will not drop into the tray, the terminals may sit on the wrong side, and you find out in a parking lot. So check three things: the group size that matches your car (Group 35 and Group 48 are the common trays here), the cold cranking amps (CCA — how much punch the battery delivers on a freezing morning), and a warranty you can actually use. Below we cover those three, plus what AGM and lithium chemistry each give you, so you buy right the first time.
This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Turbocharged engines and short-hop driving put real strain on a starting battery, so the picks below are grouped by tray size and budget tier rather than just raw cranking numbers. The goal is simple: match your WRX’s tray, terminals, and charging system to the right chemistry before you spend a penny on a wrx car battery.
Top Picks
How To Choose The Best WRX Car Battery
Start with your old battery, not the internet. The label on the unit you are pulling out tells you the group size, the terminal layout, and whether it is an AGM or a flooded battery. Match those three and you avoid the most common return reason with car batteries: it will not sit in the tray or the cables will not reach.
Group size and terminal layout come first
Group size is the physical box the battery fits into — length, width, and height checked as one standard. A Group 35 battery is a different footprint from a Group 48, so measure the tray and the hold-down before you order. Then check which side the positive and negative posts sit on, because a battery with the terminals reversed will not connect without stressing the cables.
Cold cranking amps and reserve capacity
Cold cranking amps (CCA) measure the battery’s punch at cold temperatures — the number that gets a turbo engine turning on a frosty morning. Reserve capacity (RC) is the minutes of backup power the battery can supply if the alternator quits, which matters more than most buyers realize if you run accessories. Higher CCA only helps if your tray and charging system can support the larger battery.
AGM versus flooded versus lithium
AGM (absorbed glass mat) batteries hold their acid in fiberglass mats instead of free liquid, so they resist spills and vibration and suit start-stop cars. Flooded batteries are the older design and simply will not accept a downgrade if your car was built for AGM. Lithium iron phosphate (LiFePO4) packs are lighter and cycle far longer, but they cost more and demand a compatible charger. Never step a factory AGM car down to a flooded unit — the charging system will not keep it healthy.
Side-by-Side Comparison
| Model | Best For | Group Size | CCA | Capacity | Amazon |
|---|---|---|---|---|---|
| Group 35 Car Battery AGM (Marxon)★ Best Overall | Most WRX owners wanting a direct-fit AGM | Group 35 | 650 CCA | 55 AH | Amazon |
| Mighty Max MM-H5Biggest Reserve | Buyers needing a Group 47 tray | Group 47 | 680 CCA | 60 AH | Amazon |
| Weize Platinum AGM Group 35Most Reviewed | Long service life on a modest budget | Group 35 | 650 CCA | 55 AH | Amazon |
| Goodyear 35-AGM Platinum | Brand-name confidence in Group 35 | Group 35 | 650 CCA | 55 AH | Amazon |
| Marxon Group 48 H6 | High-capacity start-stop builds | Group 48 | 760 CCA | 70 AH | Amazon |
| Goodyear 48-H6-AGM Platinum | Big Group 48 tray with reserve to spare | Group 48 | 760 CCA | 70 AH | Amazon |
| Interstate MTX-35 AGM | Buyers who want a long-life upgrade unit | Group 35 | 650 CCA | 55 AH | Amazon |
| Phnixino Lithium 94R (H7) | Weight-saving, high-output builds | Group 94R (H7) | 1800 CCA | 80 AH | Amazon |
Detailed Reviews
1. Group 35 Car Battery 55AH 650CCA AGM
Our pick — 4.5+★ from 750+ verified ratings; the strongest balance of quality and price.
The direct-fit Group 35 that skips the guesswork and starts a cold turbo engine without drama.
If you want one that simply drops into a Group 35 tray and works, this Marxon unit is the pick. That group size is a standard footprint, and this box measures 9.51 x 6.85 x 8.78 inches with the negative post on the left and positive on the right — exactly what a WRX hold-down expects. The 650 cold cranking amps (CCA — the starting punch on a cold morning) turn the motor over briskly, and the 55 AH (amp-hour capacity, roughly how much charge it stores) keeps the electronics fed between drives.
What wins people over is battery quality, and it is the most-praised trait by a wide margin — owners keep coming back to how solid it feels at the posts and how evenly it holds up. The 88-minute reserve capacity (RC — minutes of backup power if the alternator fails) gives you a buffer, and it is 12 minutes short of the Goodyear 35-AGM’s 100 RC. It is a heavy lump to lift into the tray, so plan for two hands.
The catch is charge retention. As buyers report, the results split: “While some owners mention it holds a charge for up to two weeks, others say it fails to hold a charge at all.” If you drive a lot, that is a non-issue. If your WRX sits for weeks at a time, a battery tender is worth the habit. Otherwise, the maintenance-free design means no adding water and no acid handling — just install it and go.
The install-day wins
- Correct Group 35 footprint with negative-left, positive-right posts — drop-in fit for the WRX tray.
- 650 CCA fires the engine over on cold starts; 55 AH handles accessory load.
- 88-minute reserve capacity means electronics keep running if the alternator lets go.
- Maintenance-free sealed AGM — no acid to add, no water checks.
- Three-year warranty with a US office and a stated 12-hour response window.
Where it makes you work
- Sits at 42.3 pounds — noticeably heavier than several rivals here.
- Charge retention is the mixed bag: some units sit fine for weeks, others drain fast.
Reach for this if: you want a correct-fit Group 35 AGM that installs cleanly and starts without fuss.
Think twice if: your car sits for long stretches between drives without a maintainer.
2. Mighty Max Battery MM-H5 Group Size 47
A Group 47 tray owner’s sleeper: big reserve, high capacity, and a price that does not sting.
This one earns its callout on reserve capacity. Its 60 AH capacity also tops the Group 35 Marxon’s 55 AH by 5 AH, so it stores more charge for a heavy accessory load. Both numbers line up with what buyers rave about: it just works and matches their vehicles without fuss.
Here is the thing nobody says out loud about Group 47: it is a different size from Group 35. At 9.53 x 6.88 x 7.48 inches it is shorter than many trays expect, and the size is the mixed part of this design. Some owners find it “mighty for its size,” while others say it is too small. Before you buy, measure the tray in your WRX — if it takes a Group 47, this is a strong value.
The starting side is solid. That 680 CCA beats the 650 CCA common on Group 35 batteries, and it is built for start-stop duty with a sealed, spill-proof design that resists shock and vibration. It comes with mounting screws, mounts in multiple positions (though not upside down), and ships with a three-year warranty from an ISO-certified facility. If your WRX tray runs Group 47, this is a sensible upgrade over a smaller unit.
Start-stop ready: 680 CCA and 60 AH handle repeated restarts and accessory draw without sagging.
The size question: Group 47 is not interchangeable with Group 35 — confirm your tray first or it will not seat.
The right call when: your WRX takes a Group 47 and you want maximum reserve for the outlay.
skip it if: you have a Group 35 tray — this is a different footprint entirely.
3. Weize Platinum AGM Battery Group 35
The crowd favorite Group 35 — 5,000+ buyers can’t all be wrong about a battery that just fits.
When the question is which Group 35 to trust, this is the name that comes up most. The Weize Platinum fits a standard Group 35 tray at 9.06 x 6.89 x 8.82 inches with a tapered terminal — negative left, positive right — and customers note it slots under the driver floorboard without argument. At 37.7 pounds it is lighter than the Marxon Group 35 at 42.3 pounds, which makes install that much less of a wrestling match. That lightness and drop-in fit are the two things buyers talk about most.
The specs are solid AGM fare: 55 AH capacity, 650 CCA, and a maker rating of up to 2X the cycle life of a conventional battery. If your WRX came with an AGM, this stays in AGM and avoids a downgrade to flooded, which the charging system will not keep healthy.
The one crack in the picture is longevity. Most reviewers point out it holds a charge well and is built to last, but “some mention it only lasted 6 months.” That is a minority read, but it is the honest trade-off to weigh against the fit-and-finish strengths. For the typical WRX owner who wants a Group 35 that seats cleanly and starts reliably, this remains a top value.
Fit and weight lead: a 37.7-pound Group 35 that slots into a standard tray — the fit is why owners keep recommending it.
Life varies: the flat spot is durability, with a 6-month failure in the minority that you should weigh against the cost.
Buy this for: a Group 35 tray, an AGM charging system, and a battery that fits the first time.
Look elsewhere for: a guaranteed long service life — this one wins on fit, not on longevity promises.
4. Goodyear 35-AGM Group Size 35
A Group 35 with 100 minutes of reserve and a badge that carries some weight.
Reserve capacity is where the Goodyear 35-AGM makes its case. That 100-minute RC edges the Marxon Group 35’s 88 RC by 12 minutes, giving you more cushion if the alternator drops out mid-drive. The rest of the package is standard Group 35: 55 AH capacity, 650 CCA, and a spill-proof AGM build that shrugs off shock and vibration. At 9.11 x 6.85 x 8.84 inches it fits a Group 35 tray with positive on the right and negative on the left.
It is 8.84 inches tall, and this is where the footprint gets interesting. The Mighty Max MM-H5 stands 7.48 inches tall, and that gap matters if your tray or hold-down has a low ceiling. Measure the height before you commit. Given this is a Group 35 with a short-height competitor nearby, the tall profile is worth confirming against your WRX hood clearance.
Traction with reviewers so far centers on quality and reliability, and it is early in its life as a listing. The 36-month warranty and the CE-certified factory build give it bonafides. If you want a Group 35 with more reserve than the typical value pick and the Goodyear name behind the warranty, this is a reasonable step up — just confirm the tall dimensions clear your application.
Why it earns a place
- 100-minute reserve capacity beats several Group 35 rivals on backup power.
- 650 CCA starts cold and the AGM build is spill-proof and vibration-resistant.
- 36-month warranty and CE-certified factory build.
What to check first
- At 8.84 inches tall it is a tall Group 35 — verify your hood and hold-down clearance.
The fit is on you: confirm your tray clears a tall Group 35 before ordering.
Worth it for: buyers who want extra reserve and a recognized warranty in a Group 35.
5. Group 48 H6 L3 Car Battery 70AH AGM
For a Group 48 tray that wants big capacity and a start-stop-friendly charge.
Big Group 48 trays ask for a big battery, and this Marxon delivers on paper. For a WRX running start-stop and a stack of accessories, those numbers translate directly into strong cold starts and headroom for electronics. Dimensions run 10.95 x 6.89 x 7.48 inches with an A1 terminal.
The start-stop design is the selling point. The maker claims 10% lower fuel costs per drive and 20% less CO₂, and it supports the stop-start function modern WRXs use. The maker claims a 40% faster charge time than an SLA battery, credited to new materials that improve charge acceptance. The maintenance-free, leak-proof design means no adding acid and no water checks.
At 47.3 pounds it is the heaviest AGM on this list, heavier than the 42.3-pound Group 35 Marxon by several pounds, so treat installation as a two-person job. There is no review history to lean on here, which means you are buying on specs and a three-year warranty alone. If your WRX uses a Group 48 tray and you want maximum capacity in AGM form, the specs make a strong case.
Spec-sheet standout: 70 AH and 760 CCA are the biggest AGM numbers here — ideal for start-stop builds with heavy draw.
Weight warning: at 47.3 pounds this is a two-person install, not a one-hand lift.
Suits: a Group 48 tray and a start-stop system that wants maximum reserve and cranking.
Not for: anyone who has not confirmed they need Group 48 — the footprint will not fit a Group 35 car.
6. Goodyear 48-H6-AGM Group Size 48
The biggest reserve in the line-up: a Group 48 that keeps the lights on longer.
If reserve capacity is the number you care about, this one leads. The 120-minute RC is the highest on this list, giving you two hours of backup power if the alternator quits — well beyond the 100 minutes of the Group 35 rivals. Pair that with 70 AH and 760 CCA, and it is built for a Group 48 tray that wants serious capacity and cold-cranking muscle. Physical size runs 10.87 x 6.84 x 7.47 inches with positive on the right, negative on the left.
The AGM build is spill-proof and vibration-resistant, and the maker cites up to 2X the cycle life of a conventional battery. It comes with screws for install, mounts in multiple positions (not upside down), and carries a 36-month warranty from a CE-certified factory. For a WRX running start-stop with accessories, the reserve and capacity give you headroom the smaller Group 35 units simply cannot match.
Buyer reaction is warm on quality but mixed on fit and battery life — the recurring note is that it needs to sit in the exact tray to pay off, and charge retention varies from unit to unit. Measure your Group 48 tray carefully, since a fraction off and it will not seat. With those caveats, it is the reserve king of this group.
The champion when: your WRX has a Group 48 tray and you want the longest reserve here.
Be sure first: the fit needs to be exact — measure before trusting the listed dimensions.
7. Interstate Batteries Car Battery Group 35 AGM
A Group 35 built around lead content, sold on the theory that more lead means longer life.
The pitch here is construction, not a flashy number. Interstate’s MTX design packs more lead into the plates, and the maker claims 2X the service life of a conventional lead-alloy AGM and 3X that of a conventional flooded battery. For a Group 35 tray at 55 AH and 650 CCA, it matches the capacity of the Marxon and Weize Group 35 units while betting on longevity from the material choice. It is spill-proof and vibration-resistant thanks to the AGM and VRLA (valve-regulated) build.
What owners actually praise is performance and fit — it starts immediately and drops into the vehicle without fuss, and installation is called out as easy. At 42 pounds it is in line with the other Group 35 heavies, so you are not gaining or losing much on the lift. The maintenance-free design means no acid top-ups and no water checks.
The longevity promise is where expectation and reality can drift. Battery life draws mixed reactions — some call it the best on the planet, and others report it dying after two years of use. Treat the 2X-3X claim as the maker’s, not a guarantee, and weigh it against the three-year warranty. If you want a Group 35 with a material story and a name behind it, this is a legitimate contender.
Material bet: more lead in the MTX design is the reason to pick it, and 650 CCA / 55 AH cover a Group 35 WRX tray.
Life varies: the 2X-3X claim is the maker’s, and real durability spans good runs and two-year failures.
Worth considering: for a Group 35 owner who values a heavier-lead construction and a recognized name.
Weigh carefully: if guaranteed long life is your top priority, the mixed reports mean the warranty is your real safety net.
8. Lithium Car Battery BCI Group 94R H7
The high-output outlier: a lithium pack that drops 18 pounds of weight and doubles the cranking punch.
This is the pick for someone chasing performance, not just replacement. It also weighs 24 pounds, against the 42.3-pound Marxon Group 35 — an 18.3-pound saving that comes right off the nose of the car. Owners appreciate the lightweight design and report it cranks the engine right up.
The BMS (battery management system — the circuit that guards against overcharge and overheating) provides real-time protection and self-balancing cells. The maker claims 4000+ deep cycles at 100% depth of discharge versus 300-500 for typical lead-acid, plus a 5-year warranty. It recharges in as little as 1-2 hours with a compatible lithium charger, and it fits a Group 94R (H7 / LN4) tray at 12.4 x 6.9 x 7.5 inches.
Two hard conditions come with lithium. It is Group 94R, not Group 35 or 48, so confirm your tray takes an H7 footprint before anything else. And you need a compatible lithium charger — a standard lead-acid charger will not maintain it correctly. Do not leave it unused for long stretches or connect in series or parallel. Respect those three rules and you get a light, powerful, long-cycle battery; ignore them and lithium bites back.
Performance reasons to switch
- 1800 CCA dwarfs the 650 CCA of the Group 35 AGM picks.
- 24 pounds sheds serious weight versus 42-pound lead batteries.
- 4000+ deep cycles and a 5-year warranty on the maker’s spec.
- Built-in BMS protects against overcharge, over-discharge, and overheat.
The lithium rules
- Group 94R (H7) only — it will not fit a Group 35 or Group 48 tray.
- Needs a compatible lithium charger; long idle periods and series wiring are off-limits.
Built for: a Group 94R tray and a driver who wants maximum cranking plus weight savings.
Wrong pick if: your car takes Group 35 or 48, or you cannot commit to a lithium-compatible charger.
Know the Specs
Group size and terminal layout
Group size is the standard box a battery must fit — length, width, and height as one measured footprint. Terminal layout is which side the positive and negative posts sit on. A correct group size with the wrong post orientation still fails, because the cables will not reach without stress. Measure the old battery, note the terminals, and match both before buying.
CCA and reserve capacity
Cold cranking amps (CCA) measure the punch a battery delivers at cold temperatures to turn the engine over. Reserve capacity (RC) is the minutes it can keep the electrical system alive if the alternator fails. A higher CCA helps cold starts on a turbo engine; a higher RC buys you time on the roadside. Both come from the battery’s chemistry and plate design.
AGM, flooded, and LiFePO4
AGM holds acid in fiberglass mats, so it resists spills and vibration and suits start-stop cars. Flooded batteries use free liquid and are an older design — do not downgrade an AGM car to one. LiFePO4 (lithium iron phosphate) is lighter and cycles far longer but needs a compatible charger and careful storage. Match the chemistry to what your car was built for.
Amp-hour capacity
Amp-hours (AH) tell you how much charge the battery can store. A 55 AH unit stores less than a 70 AH one, which matters if you run accessories or the stop-start function heavily. More AH generally means more weight and more space, so pick the capacity your tray and charging system actually support rather than chasing the biggest number.
Common Questions
Will a Group 35 battery fit my WRX?
What is the difference between Group 35 and Group 48 batteries?
Do I need an AGM battery if my car came with one?
What cold cranking amps (CCA) do I need for a WRX?
Can I install a WRX car battery myself?
How long does a WRX car battery typically last?
Is a lithium battery better than AGM for a WRX?
What does reserve capacity (RC) mean, and does it matter?
Can I put a larger capacity battery in my WRX?
Do I need a special charger for a lithium car battery?
The Bottom Line
For most WRX owners, the winner is the Group 35 Car Battery AGM (Marxon) because it fits a standard Group 35 tray correctly, delivers 650 CCA with an 88-minute reserve, and runs maintenance-free from day one. If you have a Group 47 tray and want maximum reserve and capacity, grab the Mighty Max MM-H5. And if you are chasing maximum cranking and weight savings, the Phnixino Lithium 94R is the one to reach for — provided your tray and charger can support it. Whichever you choose, measure first and match the chemistry, and you will avoid the one mistake that shortens every car battery’s life.
How we choose
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of November 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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