The 12-volt starting battery in a 2020 Subaru typically lasts about 3 to 5 years. Lifespan varies with climate, driving habits, and maintenance.
In practice, many owners find the battery lasting toward the middle of that range, with harsher climates, frequent short trips, or heavy electrical use shortening the window. Most 2020 Subarus use an absorbed glass mat (AGM) 12-volt battery to better handle parasitic draws from modern features, but exact longevity depends on trim, region, and care. This article focuses on the 12-volt battery; high-voltage packs in any hybrid or plug-in variant have different lifespans and replacement considerations.
12-volt battery life in a 2020 Subaru
Several factors determine how long the auxiliary battery holds a charge in these vehicles.
- Extreme temperatures (very hot summers or cold winters) accelerate chemical aging and can shorten life.
- Short trips with insufficient time to fully recharge reduce the battery’s overall conditioning.
- Parasitic electrical draws from accessories, lights, or infotainment systems when the engine is off.
- Battery type and quality (many 2020 Subarus use AGM batteries, which handle drains better but still wear out).
- Aging and manufacturing variability; even new batteries can fail earlier if they come from a weaker batch.
- Charging system health (faulty alternator or corroded connections can prevent proper charging).
In sum, climate and usage are the biggest variables; regular maintenance and a healthy charging system help maximize lifespan.
What to expect: signs of a dying battery
Watch for these indicators that your 12-volt battery may be nearing the end of its life.
- Slow engine cranking or difficulty starting the vehicle.
- Dim or flickering headlights and dashboard lights.
- Battery warning light illuminated on the dashboard.
- Electrical accessories acting inconsistently or failing to power up.
- Corrosion around terminals or a swollen battery case.
- Battery fails a load test or cannot hold a charge after a drive.
When multiple signs appear, it’s wise to have the battery tested by a professional who can check both the battery and the alternator.
How to extend life: practical tips
Maintenance and best practices
Adopt these habits to maximize the life of your 2020 Subaru’s 12-volt battery.
- Keep terminals clean and tight; remove corrosion with a baking soda solution and a brush.
- Have the charging system (including the alternator and belt) tested if you notice symptoms.
- Avoid leaving interior/exterior lights on when the engine is off; use a battery maintainer for long parking periods.
- Drive regularly for 20–30 minutes to fully recharge and exercise the alternator.
- Use the correct battery type ( AGM is common for newer Subarus) and replace at recommended intervals.
- In cold climates, consider parking in a sheltered or heated area to reduce cold-weather strain.
With proper care, many owners see 12-volt batteries perform well into years 4–6, though individual results vary by circumstances.
What to do if the battery dies
Immediate steps and options if you experience a no-start condition:
- Attempt a jump-start with another vehicle or a portable jump pack.
- If the engine starts, drive to a service location to test the battery and charging system promptly.
- If the car won’t start, contact roadside assistance rather than repeated cranking, which can damage the starter and electrical system.
Frequent failure after a jump usually indicates a failing battery or alternator; proactive replacement is typically more cost-effective than repeated troubleshooting.
Summary
For a 2020 Subaru, plan on a 12-volt battery lasting roughly 3 to 5 years under typical conditions, with longer life possible in mild climates and with careful maintenance. Monitor for symptoms of weakness, test the charging system regularly, and replace the battery before it leaves you stranded—especially if you rely on advanced features or drive mainly on short trips. If you’re in doubt, have a qualified technician inspect the battery and alternator to determine the correct replacement interval.