How Often Should You Start Your Car to Keep the Battery Charged?

A car that sits on the drive all week is a car with a slowly draining battery. Even switched off, it keeps powering the alarm, the clock, the keyless entry and the computers. Leave it long enough, add a cold snap, and one morning you turn the key and get a click.

The fix is boring: use the car a little, regularly. The hard part is remembering to, because a car you don't need is a car you don't think about. That's common if you work from home, own a second car, look after a car for someone who's away, or have a parent who only drives now and then.

Here's how long a car can sit, how often to start or drive it, why winter makes it worse, and a simple reminder plan.

The short answer

• A healthy battery should cope with about two weeks of not being used. The AA says most modern cars with a fairly healthy battery "should last at least 2 weeks, without needing to be started up" (The AA).
• If you're not sure about the battery, use the car once a week. The AA's advice is a journey of 15 minutes or more, or to start the engine once a week and let it run for about 15 minutes.
• A proper drive is better than idling. Interstate Batteries recommends driving "once a week for at least 30 minutes at a time at highway speeds" (Interstate Batteries).
• Going two weeks or more between drives in winter? Use a battery maintainer (also called a tender or trickle charger).

How long can a car sit before the battery dies?

There's no single number, because it depends on the battery's age and condition, the weather, and how much power the car draws while it's off. The main motoring organisations give similar ranges:

Source	What it says
The AA	A fairly healthy battery should last "at least 2 weeks" without starting the car
RAC	Up to two weeks should be fine; "If a car battery sits unused for more than a month, then the battery can start to drain"
Interstate Batteries	A car battery "can last about four weeks to two months before it dies"

Treat two weeks as the safe limit and a month as the point where you're taking a chance, especially with an older battery or in cold weather. The steady background drain has a name, parasitic drain: the car's electrical system "continues to draw power from the battery—despite the vehicle being shut off", as Interstate puts it.

Why a car battery goes flat more easily in winter

Cold weather saps a battery's power. AAA puts numbers on it: "a car battery loses a third of its power in freezing weather", and "if the temperature drops to zero or below, your battery has only HALF its power" (AAA Club Alliance). That's a US page, so zero means 0°F, about -18°C.

The same AAA page lists the things that make a winter failure more likely:

• the battery is more than three years old
• you take a lot of short trips, turning the car on and off often
• the car goes weeks or months without being used

If two or three of those describe your car, it's the one that won't start on the first cold morning.

Start it, or drive it?

This is the question most people ask, and the sources don't fully agree.

The AA says you can either take "a journey of 15 minutes or more" or "start the engine once a week and allow it to run for about 15 minutes. This will re-charge the battery and help keep the engine in good condition."

Interstate Batteries is more sceptical about idling: "No, you can't charge a car battery while idling. At best, it'll charge the battery a few amps" (Interstate Batteries). Its advice is a weekly drive of at least 30 minutes at highway speeds.

A practical way to read both:

• Best: a real drive of 20 to 30 minutes once a week, including some faster roads.
• If you can't drive it: running the engine for about 15 minutes once a week is the AA's fallback, and it's better than nothing.
• Never run the engine in a closed garage. The AA warns that exhaust fumes can be toxic: pull the car out onto the drive first.
• Short hops don't count. A five-minute trip to the shop uses the battery to start the engine and gives little back.

What about electric and hybrid cars?

EVs still have a small 12-volt battery that runs the locks, lights and computers, and it can go flat too. The AA says pressing the start button so the "ready" light comes on operates the charging system, and "doing this for 10 minutes once a week should keep the 12-volt battery topped up."

If the car will sit for more than two weeks

Holidays, a long hospital stay, a winter abroad, a student car left at home: if nobody can drive it, plan for the battery instead of hoping.

• Use a battery maintainer. The AA suggests connecting the battery to a "mains-powered battery maintainer". AAA says that "if you consistently go two weeks or longer without using your car during the winter, invest in a battery tender." The RAC's alternative is to disconnect the battery or use a trickle charger. (Check the handbook first: on some cars, disconnecting the battery may reset settings.)
• Think about the handbrake. The AA notes that brakes can seize when a car is parked for a long time with the parking brake on. It suggests releasing it and moving the car back and forth a short distance from time to time. (Only do that where the car is safe without the handbrake on, on level ground, in gear or in Park, ideally with the wheels chocked.)
• Check the tyres before you drive. The AA advises checking all the tyre pressures after a long period parked up, and inflating them if needed.

Small habits that help the battery

From the AAA winter battery checklist:

• Park in a garage when you can.
• Turn off the lights, wipers and heater before you switch off the engine.
• Unplug phone chargers and USB cables when you turn the engine off.

When to get the battery tested

AAA says car batteries "typically last three to five years": often five or more in cooler northern climates, and about three in hot southern ones. Its advice is that "after three years, test the battery yearly" (AAA). Autumn is the sensible time, before the first frost rather than after the first failed start.

Warning signs AAA lists include dim headlights, clicking sounds when you turn the key, a slow crank, electrical issues, a battery warning light, needing jump-starts, a bad smell from the battery and a bulging battery case. If you see these, get it tested now rather than waiting for the weekly drive to rescue it.

A simple reminder plan for a car you don't use much

When	Reminder
Every week (pick a quiet slot, such as Sunday 11am)	"Take the car out for 20 to 30 minutes today, some of it on faster roads."
Every week, for an EV	"Switch the car on to Ready for 10 minutes to top up the 12-volt battery."
Once a month	"Check the tyre pressures, and look for a battery warning light."
Every October, once the battery is 3+ years old	"Book a battery test before the cold weather."
The day before you go away for 2+ weeks	"Plug in the battery maintainer, and leave the handbrake as the handbook advises."
The day you get back	"Check the tyre pressures before driving."

A weekly drive is easy to plan and easy to skip, which is why it's worth a reminder you'll actually notice. It's also worth doing for someone else: a parent who has stopped driving much, or a neighbour's car you've promised to keep ticking over. For more regular jobs, see our guides to monthly vehicle safety checks between services and rotating tyres and other car checks. If you drive in Quebec or British Columbia, there's also our guide to when winter tyres become mandatory.

How ReminderIt can help

ReminderIt rings your phone at the time you choose and reads your reminder out in a natural voice: "It's Sunday. Take the car out for a 20-minute drive today." A phone call is harder to swipe away than a notification, and if you miss it, the reminder comes through on WhatsApp too.

You can set it up just by sending a WhatsApp message such as "Call me every Sunday at 11am to take the car for a drive", or on the website. Weekly, monthly and one-off reminders all work, so the whole plan above can go in at once.

If it's a parent's car, you can have the reminder ring their phone instead, or as well. They confirm their number once with a short verification call, so nobody gets calls they didn't agree to. See how to set a reminder for someone else.

There's a 7-day free trial with 7 reminder calls in most countries, including the US and Canada. On a UK number the trial includes 3 calls, because calls to the UK cost more. After that it's one plan: US$7 a month, or ₹299 a month in India.

The bottom line

A healthy car battery usually survives about two weeks without the car being used, and much less happily a month or more, particularly in cold weather or once it's over three years old. If the car sits most of the week, drive it for 20 to 30 minutes once a week. If you can't drive it, the AA's fallback is to run the engine for about 15 minutes weekly, outdoors and never in a closed garage. For two weeks or more away, use a battery maintainer. And from three years old, get the battery tested every autumn.

Sources: The AA, Laying up and maintaining your car; RAC, How long can you leave a car without driving it?; AAA Club Alliance, Will your car battery survive winter?; AAA, When to replace your car's battery; Interstate Batteries, How to maintain your sitting car battery and How long you have to drive to charge your car battery. This guide is general information. Your car's handbook comes first, especially for EVs and cars with stop-start systems.