2015 Subaru Crosstrek — Battery Size, Group & CCA

Quick answer

• BCI group size: Group 25 (a.k.a. 25)
• Cold cranking amps (CCA): aim for 550–650 CCA (factory batteries are often mid-400s; more CCA is recommended for cold climates)
• Reserve capacity (RC): typically ~100–130 minutes (target 120 min if available)
• Battery type: Conventional flooded from factory; AGM is an excellent upgrade but not required (no start/stop on 2015 Crosstrek)
• Terminal layout: Top-post SAE; positive on the left (Group 25 orientation). Do not substitute Group 35 (opposite polarity) unless cables reach and polarity is verified.
• Physical dimensions (Group 25): about 9.1" L × 6.9" W × 8.9" H (230 × 175 × 225 mm)
• Dual-battery setup (diesel): Not applicable — Crosstrek gasoline only for this model year

Replacement battery options

Popular, readily available choices in Group 25. Part numbers vary by retailer/line; match by BCI group, CCA, and RC.

• Interstate Batteries — Group 25 flooded (MT/MTP series) or Group 25 AGM (MTX series)
• DieHard — Group 25 Gold (flooded) or Platinum AGM (Group 25)
• Optima — YellowTop Group 25 (deep-cycle AGM) for accessory-heavy builds; RedTop Group 25 for strong starting performance
• Odyssey — Performance/Extreme Series Group 25 AGM
• ACDelco — Group 25 options in Gold (enhanced flooded) and AGM lines

Tip: Choose the highest CCA and RC that fit your budget and confirm the case height clears the hold-down and hood.

AGM vs flooded — which does this vehicle need?

• Requirement: The 2015 Crosstrek does not require an AGM; a quality flooded Group 25 meets OEM spec.
• When to choose AGM: If you drive short trips, live in very cold climates, run accessories (audio, lights, dash cams), or want better vibration resistance and lower self-discharge, an AGM Group 25 is a worthwhile upgrade.
• Charging system compatibility: The Subaru charging strategy is AGM-friendly. No modifications are needed; ensure the battery is fully charged before installation for best life.

Post-installation relearn / reset procedure

• Memory saver (optional but recommended): Using a 12 V memory saver through the OBD-II port can preserve presets and reduce relearns.
• Install notes: Clean terminals, apply a light corrosion protectant, and tighten clamps snugly (do not overtighten). Verify positive cable to positive post.
• Initial start and idle learn:
  1. Turn off all accessories. Start the engine and let it idle for 10 minutes without touching the throttle.
  2. Turn the A/C on and idle another 5 minutes. This helps the ECU/idle air control adapt to voltage changes.
• Power window initialization (front windows with auto): With ignition ON, fully lower each window and hold the switch down for 2–3 seconds; then fully raise and hold up for 2–3 seconds. Repeat once if auto-up/down doesn’t work immediately.
• Radio/clock: Re-enter clock and radio presets. Pair Bluetooth again if needed.
• VDC/ABS lights: Low voltage during the swap can set temporary warnings. Drive straight at city speeds for a few minutes; lights usually clear on their own. If not, scan for codes.
• TPMS: Sensor pairing isn’t lost by a battery swap.

Signs of a failing battery

• Slow crank, especially after the car sits overnight or in cold weather
• Dim headlights at idle or flickering interior lights
• Multiple warning lights (VDC/ABS, power steering, check engine) appearing together after startup
• Electrical glitches (radio resets, window auto function erratic)
• Battery case swelling or corrosion buildup on terminals

Common battery issues for this generation

• Undersized OE battery: Many Crosstreks shipped with modest-CCA flooded units that degrade quickly in cold climates. Upgrading to a higher-CCA Group 25 or AGM improves reliability.
• Short-trip driving: Frequent short hops don’t fully recharge the battery; sulfation builds and capacity drops. Use a smart maintainer if the car sits or mostly does short drives.
• Parasitic draws: Accessories (dash cams, phone chargers), aging head units, or leaving dome/cargo lights on can drain the small stock battery overnight.
• Voltage sensitivity: Subaru ECUs and stability systems are sensitive to low voltage; borderline batteries can trigger nuisance warning lights and odd transmission/idle behavior.
• Corrosion or loose grounds: Check and clean the negative battery-to-chassis ground and the hold-down. A loose battery can vibrate, shortening battery life.

Choose a Group 25 replacement with at least 550 CCA and around 120 minutes of RC for best results; consider AGM if you want maximum durability and reserve.

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