If a car sits, drive it for at least 20 minutes every one to two weeks, and weekly is the safer rhythm. Starting the engine and letting it idle does not recharge the battery, so a few minutes of warming up in the driveway does less than most people think. Eugene and Springfield winters are wet and mild, with a January normal low of 34.7°F, and that is the kind of weather that finds a weak battery. Our ASE-certified technicians test batteries and charging systems for drivers across the metro, and our shop repairs cars for drivers in Eugene, Oregon.
Last updated October 2026
Key takeaways
- Drive a parked car for 20 minutes every 1 to 2 weeks, and weekly when you can. Idling cannot charge the battery sufficiently (Battery University).
- AAA reports a battery loses about 35% of its strength at 32°F and about 60% at 0°F.
- Ethanol blended gas can lose combustibility in 1 to 3 months and regular gas in 3 to 6 months (AAA), and Oregon requires E10 in nearly all gasoline.
- Keep tires at the placard pressure on the driver’s door jamb and never above it (Michelin).
- For a few weeks or more, connect a battery maintainer or disconnect the battery cables (Hyundai).
Car not starting right? We test and replace batteries and charging systems for drivers in Eugene and Springfield, and Blue Rose Auto holds a 4.9★ rating on Google. Call (541) 641-8877.
The Quick Answer Is Every Week or Two, and Driving Beats Idling
Drive a parked car for 20 minutes at least every two weeks, and every week if you can manage it. Published advice does not agree to the day. AAA tells drivers to drive an idle car once a week. The Motorist Assurance Program says at least once a week for about 15 to 20 minutes. Hyundai’s owner site says to disconnect the battery cables or use a battery maintainer if the car will sit for a few weeks. We treat weekly as the default and two weeks as the outer limit for a healthy, newer battery.
The reason is the battery. Battery University points out that a motor at idle or at low speed cannot charge the battery sufficiently. A car that is started and left running in the driveway spends starter current and gets little back. A long drive does the opposite, and Hyundai notes that long freeway drives can fully charge a battery while short trips cannot.
| Idling in the driveway | Driving for 20 minutes |
|---|---|
| Gets 0 miles per gallon | Can charge the battery on a long drive |
| Burns a quarter to a half gallon an hour | Warms the engine faster |
| Cannot charge the battery sufficiently | Relaxes most flat spots in tires |
The idling figures come from FuelEconomy.gov. Michelin says normal highway speeds for over 20 minutes relax most flat spotting.
Does Idling Charge the Battery?
Not enough to matter. Battery University says a motor at idle or low speed cannot charge a starter battery sufficiently, and that repeated shortfalls lead to sulfation. FuelEconomy.gov adds that idling gets 0 miles per gallon, and the Department of Energy says idling for as little as 10 seconds uses more fuel than shutting off and restarting.
Should You Start Your Car Every Day?
No. A start that lasts a few minutes asks the battery for starter current and gives it almost no time to earn that back. Hyundai says short trips do not give a battery enough time to recharge. One 20 minute drive a week does more for a parked car than seven driveway starts,.
What Happens When a Car Sits Unused
A parked car ages in the battery, the fuel, the tires and the fluids, each on its own clock.
Battery Drain and Sulfation
A battery drains even when the car is off. Hyundai says infrequent use passively drains it, because alarms, keyless entry and the computer’s memory keep pulling small current around the clock. Cold makes it worse, and AAA puts typical battery life at 3 to 5 years, closer to 3 with today’s electronics.
Sulfation is the lasting damage. Battery University explains that it happens when a lead acid battery is deprived of a full charge, which is common with starter batteries in cars driven around town with load-hungry accessories.
You can read your own battery with a multimeter. A healthy battery that has rested reads 12.65 V or more. Battery University’s table, from the Battery Council International standard, gives the readings at about 78°F (26°C) after a 24 hour rest, and a reading taken right after driving looks better than the battery really is, so let the car sit before you measure.
| Resting voltage | State of charge |
|---|---|
| 12.65 V | About 100% charged |
| 12.45 V | About 75% charged |
| 12.24 V | About 50% charged |
| 12.06 V | About 25% charged |
| 11.89 V | About 0% charged |
If the number is low even after a long drive, the battery may be worn out, or the charging side may be the problem. A slipping drive belt is one cause, and knowing when alternator belt replacement is due is worth checking before you buy a new battery.
Fuel System and Old Gas
Gas has a shelf life, and ethanol shortens it. AAA says gasoline lasts about 3 to 6 months before it goes bad, while ethanol blended gas can start losing combustibility in as little as 1 to 3 months. The U.S. Department of Energy reports that Oregon requires all gasoline sold in the state to be blended with at least 10% ethanol (E10), with octane 91 and above exempt. So for most Oregon drivers, the shorter clock applies.
AAA also says condensation can put water droplets into fuel, which is why it wants the tank three-fourths full or fuller on a car that sits. If gas will stay in the tank for more than a few months, AAA recommends a fuel stabilizer. Then drive 5 to 10 miles so the treated fuel reaches the whole fuel system. When a car has sat on old gas and runs rough, we repair fuel systems and clear out what old gas leaves behind, starting with a diagnosis.
Tires and Suspension
A parked tire flattens where it touches the ground. Michelin says this flat spotting is temporary, shows up after days or weeks parked, and goes away with driving. It is annoying, not damaging. You feel it as a vibration in the steering wheel, and if that vibration does not clear with driving, Michelin says the tire deserves a professional look.
Pressure matters more than most people expect. Cold air lowers tire pressure, FuelEconomy.gov notes, and Michelin says to keep tires at the placard pressure on the driver’s door jamb. Do not inflate beyond the placard, and certainly do not over-inflate. We check tire pressure and wheel alignment on cars that sat, and a vibration that stays after a long drive gets a closer look. If the car also wanders or clunks, we repair suspension and steering too.
Engine Oil and Fluids
Fluids age on the calendar, not only by mileage. AAA says that if a car is due for a brake fluid or coolant change, the work should be done before it goes into storage. Deteriorated fluids can lead to rust and corrosion. The same logic applies to engine oil, and we change oil for cars that sit by the owner’s manual time interval as well as the miles.
Rodents and Wiring
A quiet car in a carport or garage attracts mice and rats. They chew wiring. AAA says to seal the tailpipe, the air filter inlet and any other reachable opening. Copper wool works better than steel wool because rodents dislike the taste. Hard evidence for dryer sheets and mothballs is difficult to come by. If they already moved in, we remove rodents and repair the damage, and whether insurance covers rodents eating car wires in Oregon depends on your policy.
The Best Schedule for a Car You Rarely Drive
Drive it weekly for about 20 minutes, with part of the trip at highway speed, and run the air conditioning, heater, lights and wipers while you do. A run out the Beltline and onto I-5 to the next exit and back does more for a parked car than a week of short hops. The engine gets fully warm, and the charging system has time to work.
Monthly Deep Exercise
Once a month, drive for 30 to 45 minutes. Then use the stop as a checkup. Look at tire pressure, fluid levels, the ground for drips, the belts and hoses, and the engine bay for nesting material or chewed wires.
Seasonal Adjustments
Cold lowers battery strength, so the margin shrinks from November through February. Add a drive before any hard freeze and, if the battery is more than three years old, have it tested in the fall.
How Often Should You Drive a Car?
At least once a week, for 20 minutes or more, with some of it at highway speed. A daily driver with only short trips still counts as sitting from the battery’s point of view, so give it one longer drive a week. We would rather see a customer take a Sunday run to Coburg and back than buy a charger and forget to connect it.
How Often Should You Start a Car in Storage?
For a car in storage, either drive it properly every one to two weeks or put it on a maintainer. Pick one, and never just start it, idle it for five minutes and shut it off. A short idle drains starter current, does not charge the battery sufficiently, and warms the engine more slowly than driving does.
| How long it sits | What it needs |
|---|---|
| Every week | Drive 20 minutes |
| A few weeks | Connect a battery maintainer or disconnect the battery cables |
| 1 to 3 months | E10 gas starts to lose combustibility |
| 3 to 6 months | Regular gas goes bad, so add a stabilizer |
| Long storage | Consider jack stands for the tires |
The weekly drive comes from AAA and the Motorist Assurance Program, the few weeks row from Hyundai, the gas rows from AAA and the jack stand note from Michelin.
Short Storage, Up to a Month
This is the easy case. Drive it every week or two for 20 minutes with some highway speed, check the tire pressure first, and keep the tank at least three-fourths full.
Storage Over a Month
Prepare the car so it does not depend on anyone driving it.
- Put the battery on a maintainer, or disconnect the battery cables. The Motorist Assurance Program says a maintainer keeps the battery charged without overcharging it, and AAA suggests attaching a tender and removing it before driving.
- Fill the tank to at least three-fourths, add a fuel stabilizer, then drive 5 to 10 miles so it circulates (AAA).
- Set tire pressure to the driver’s door placard and no higher, and consider jack stands for long term storage (Michelin).
- Seal the tailpipe and air inlet, using copper wool if you can, and store the car dry, with desiccant packs and a breathable cover if the garage is damp (AAA).
- Change brake fluid or coolant that is due before the car goes into storage (AAA).
Boats and RVs add steps of their own, and winterizing and storing an RV or boat in Oregon is a different job.
Coming Out of Storage
Check the oil and tire pressures before the first drive. Expect the brakes to feel rough for the first few stops while surface rust wears off the rotors. If it does not smooth out, our technicians inspect brake systems before you head onto the highway. If the engine cranks slowly or clicks, how to tell if the starter is bad comes down to whether the battery tests healthy. After any jump start, drive at least 20 minutes and do not shut the engine off at the first stop.
Battery Maintainer or Disconnect
Either one works for a few weeks or more, according to Hyundai. A maintainer holds the battery at full charge and needs a power outlet. Disconnecting the cables stops the slow drain but can reset settings such as radio presets and the clock, so check the owner’s manual first.
Starting Your Car in Cold Weather in Eugene and Springfield
The weekly drive still applies in winter, and cold just leaves less margin. AAA reports a battery loses about 35% of its strength at 32°F and about 60% at 0°F. A cold engine can need up to twice the current to start. A battery that was borderline in October can leave you stuck in December, usually on the one morning you have somewhere to be.
Here in the valley the cold is not extreme. It is not rare either. The National Weather Service’s Eugene climate normals for 1991 to 2020 are in the table. A normal January low sits just above freezing, so frosty mornings are routine.
| Measure | Eugene |
|---|---|
| January normal low | 34.7°F |
| December normal low | 34.3°F |
| Record low, December 1972 | 12°F below zero |
| Record low, January 1957 | 4°F below zero |
| Temperature | Strength lost |
|---|---|
| Normal conditions | No loss |
| At 32°F | About 35% loss |
| At 0°F | About 60% loss |
A battery in its third to fifth year is the one that fails on the first cold morning, since AAA says the average battery lasts 3 to 5 years.
- Fit in an extra drive before and during a hard freeze rather than waiting out the week.
- Do not idle for 15 minutes to warm up. FuelEconomy.gov says most manufacturers recommend driving off gently after about 30 seconds, and the engine warms faster being driven.
- Never run the engine in a closed garage, even briefly.
- If the battery is three or more years old, test it in the fall, and plan on replacing the battery every three to five years.
Wet Winters and a Parked Car
Dampness is the Willamette Valley’s quieter problem. A damp carport collects moss and moisture, and a car that rarely moves invites mice. Wipers, tires and lights need the same fall attention, and a winter car maintenance checklist for Eugene and nearby areas walks through them.
How Long Can a Car Sit Without Being Started?
A healthy battery in a newer car will often still start the car after two to four weeks. No source sets a fixed limit, though, and it varies with the battery’s age and the car’s electronics. Hyundai’s guidance is to disconnect the battery cables or use a maintainer if the car will sit for a few weeks, and we think that is the safe line. Newer cars with alarms, keyless entry and connected services draw more current than older ones.
Fuel is the other clock. AAA’s numbers are 1 to 3 months for ethanol blends and 3 to 6 months for regular gas.
Hybrids and EVs Have a 12-Volt Battery Too
The big traction battery is not what wakes the car up. The Department of Energy says a hybrid’s low-voltage auxiliary battery provides the electricity to start the car before the traction battery engages. An electric car’s auxiliary battery powers its accessories. That small battery drains from passive use like any other, as Hyundai notes. Treat it like any other car. Drive a hybrid or EV on the same weekly to two-week rhythm and follow the owner’s manual for the high-voltage battery. We repair hybrids and repair Tesla vehicles at our Springfield shop.
How Long Can You Keep a Car Running While Parked?
A modern engine can idle a long time without harm, but it gains little. FuelEconomy.gov says idling can use a quarter to a half gallon of fuel an hour depending on engine size and air conditioning use, and that idling gets 0 miles per gallon. Idle when you need the defroster to clear the glass. Do not use it as a substitute for driving the car. Past about 10 seconds, shutting off and restarting costs less fuel (Department of Energy).
How We Check a Car That Sat for Weeks
When a car comes in after weeks of sitting, we work through the same short list. Nothing exotic. It is standard shop practice, and it catches what sitting causes.
- We test the battery and the charging system, reading resting voltage and checking what the alternator puts out.
- We check fluid levels and look under the car for leaks.
- We set tire pressure to the placard and feel for flat spot vibration on a test drive.
- We inspect belts and hoses and look for nesting material or chewed wiring.
- We scan for stored trouble codes.
The first 15 minutes of diagnosis are free. After that it is $100 an hour, credited toward the repair if you approve it, and repairs carry a 3 year, 36,000 mile warranty. If a car will not start at all, we scan and diagnose a car that will not start before we recommend parts. You can find us at 3436 Olympic St in Springfield, OR 97478, or call (541) 641-8877.
Conclusion
For a car that sits, the weekly 20 minute drive beats every shortcut. Idling does not recharge the battery, ethanol blended gas starts to age in 1 to 3 months, and past a few weeks a maintainer or disconnected cables do the work for you. Skip the driveway idle.
Blue Rose Auto opened in 1994, and our ASE-certified technicians work on batteries, starters and charging systems for drivers in Eugene and Springfield, Oregon. If the car has been sitting and something feels off, bring it in before the first cold morning does it for you.
Frequently Asked Questions About Starting a Parked Car
How often should you start your car if you do not drive it?
Drive it for at least 20 minutes once a week, and treat two weeks as the outer limit for a healthy, newer battery. Starting the engine and letting it idle does not recharge the battery, because Battery University notes a motor at idle or low speed cannot charge it sufficiently.
Is it better to idle or drive a parked car?
Drive it. Battery University notes that a motor at idle or low speed cannot charge a battery sufficiently, and FuelEconomy.gov says idling gets 0 miles per gallon and burns a quarter to a half gallon of fuel an hour. Twenty minutes on the road can charge the battery, warms the engine faster and relaxes most tire flat spots.
How often should you start a car in storage?
Drive it for 20 minutes every one to two weeks, or connect a battery maintainer or disconnect the battery cables if it will sit for a few weeks. Do not start it, idle it for five minutes and shut it off. That spends starter current and never gives the battery a real charge.
How often should you start your car in the winter or cold weather?
Keep the weekly drive. AAA reports a battery loses about 35% of its strength at 32°F and about 60% at 0°F, so a cold snap leaves less margin, and an extra drive during a hard freeze is cheap insurance. Eugene’s January normal low is 34.7°F according to the National Weather Service.
How long can a car sit without starting?
A healthy battery in a newer car will often still start after two to four weeks, but no source sets a fixed limit. On Battery University’s chart, a resting 12.45 V is about 75% charged and 12.24 V is about 50%. Older or weaker batteries give out first.
Does starting a car every day drain the battery?
A short daily start can leave the battery lower than before. Hyundai notes short trips do not give a battery enough time to recharge, and Battery University notes idling cannot charge it sufficiently. A start and idle takes starter current and returns little. Drive for 20 minutes once a week instead.
How long do you drive a car after a jump start?
Drive at least 20 minutes on real roads, with some highway speed, and do not shut the engine off at the first stop. Idling will not do it. Then have the battery and charging system tested, because a car that needed a jump has a cause worth finding.
Should you start an electric or hybrid car if it sits?
Yes. Hybrids and EVs carry a low-voltage auxiliary battery that starts the car before the traction battery engages (U.S. Department of Energy), and Hyundai notes a parked battery drains passively. Drive it on the same weekly rhythm and follow the owner’s manual for the high-voltage battery.
How long does gas last in a parked car?
AAA says regular gasoline lasts about 3 to 6 months, and ethanol blends can lose combustibility in 1 to 3 months. Oregon requires E10 in nearly all gasoline, so assume the shorter clock. For a longer sit, add a stabilizer, drive 5 to 10 miles, and keep the tank three-fourths full or fuller.
What do you check when you come back to a car that sat?
Check tire pressure against the door placard, oil and other fluid levels, battery voltage, belts and hoses, and signs of rodents. Our ASE-certified technicians run that check, and the first 15 minutes of diagnosis are free, then $100 an hour, credited to the repair if you approve it.
Sources
- AAA Oregon, winter battery preparation
- AAA, how to keep gas from going bad
- AAA, tips for idle vehicles
- Battery University, BU-903 state of charge
- Battery University, BU-804b sulfation, February 2024
- FuelEconomy.gov, cold weather and fuel economy
- FuelEconomy.gov, driving more efficiently
- U.S. Department of Energy, Fact of the Week 1239, May 2022
- U.S. Department of Energy, Oregon ethanol laws and incentives
- U.S. Department of Energy, how hybrid electric cars work
- Michelin, tire flat spotting
- National Weather Service Portland, Eugene climate book, January
- National Weather Service Portland, Eugene climate book, December
- Hyundai Owners, extending battery life
- Motorist Assurance Program, January 2026
Related Guides
- How Often Should You Replace a Car Battery? Oregon Wet-Winter Guide
- Winter Car Maintenance Checklist for Eugene and Nearby Oregon Areas
- Wheel Alignment vs Front End Alignment Explained for Oregon Roads
- What to Do When Power Steering Goes Out Before Damage Gets Worse
- How to Check Transmission Fluid Before Shifting Problems Start
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