How long can a car sit before the battery dies?
What we would buy
- NOCOBoost GB40 1000A jump starter
Holds its charge for months; top it up every few months.
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Why parked cars go flat
Modern cars draw a small current all the time for the alarm, keyless entry and electronics. Over weeks, that drains the battery, and cold weather cuts what is left. Short trips do not put enough charge back.
How to keep it starting
- Drive for more than 20 minutes every couple of weeks, as the RAC suggests.
- Plug in a battery maintainer if you have a driveway or garage.
- Turn off dash cam parking mode if the car will sit for a while.
- Keep a charged jump starter in the house so you are not stuck.
Where to buy
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Frequently asked questions
Does idling the engine charge the battery?
Only slowly. A proper drive of 20 minutes or more does far more.
Do electric cars have the same problem?
They have a separate 12V battery that can go flat too, which stops the car switching on.
Should I disconnect the battery?
It stops the drain but can reset settings and alarms. A maintainer is usually better.