The effects of cold weather on car batteries

In extremely cold conditions the chemical reaction in a battery slows down. This provides less energy which makes starting the engine more difficult. The cold can reduce a battery’s capacity by up to a third. It also reduces the battery’s ability to accept charge, so it won’t recharge as quickly when you are driving.

On top of this, during the winter we are more likely to use a whole host of our cars electrical items, putting more load on the battery. With shorter periods of daylight we use our headlights more frequently, along with heaters to defrost the car as well as keeping us warm. All this puts strain on a battery that already has a reduced capacity. When a battery is unstable, vehicles with stop start technology can suffer too. The stop start function may cease operating which will have a negative impact on the vehicles fuel consumption and will increase your fuel costs.

Winter car battery tips

Storage and winter care

The first step towards helping your battery to perform in cold weather is to keep it warm. Park it in your garage if possible, a heated garage is even better. This will prevent the battery experiencing the extreme cold so it will behave as normal.

If you are planning to store your car for a longer period of time over the winter, use a battery maintainer. This will charge the battery periodically, something that usually happens when driving.


Before the cold weather sets in, it is a good idea to have the battery and electrical system checked. It is also wise to check battery cables, posts and security, looking out for anything loose or corroded. Check the cables are firmly secured. If the battery has shown any signs of struggling before, or is over five years old, replacing it at your convenience could save you the trouble of battery failure in the depths of winter.

You can also use a battery charger/optimiser to maintain charge levels. This keeps the battery in good condition. A fully charged battery has less chance of freezing than a discharged battery, so keeping up the charge will help to protect against the cold refer to the vehicle hand book to make sure you connect the charger in the correct way.

When you finish your journey, be sure to switch off any electrical equipment in the car before you switch off the engine. If you don’t, the battery will try to power these too as you start the car, adding an extra drain that could make starting the vehicle more difficult. It’s best to disconnect sat navs, ipods, phone chargers and DVD players too, as they could drain the battery if left plugged in. Take extra care not to leave any electrical items on when you leave the car.

Tips and tricks for starting your car

If you do experience battery problems due to the cold, you may struggle to start your car. Here are some tips to get you going.

  • Switch off all electrical items when starting the car.
  • Dip the clutch to reduce the load on the battery when attempting to start the car.
  • Wait between attempts to start the car. This gives the battery time to recover, and it may have warmed a little.
  • Refer to the owner’s manual for any instructions on cold starting.
  • If none of the above works, you could try to jump-start the battery. This should be done with care, check your owner’s manual and read our jump starting instructions for further advice.

If your battery will not start, you may need it replacing. The RAC car battery service offers manufacturer quality car batteries fitted by trusted technicians on the day you order (if ordered by 2pm).

Get a quote for a new battery

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