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Driving with Jens: When should you plug your vehicle in?

You can probably still start your car without plugging it in at -25 C or colder, but you shouldn’t.
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Winter is here, and I’ve been asked a lot about when to plug your vehicle in at night so that you can rely on it starting for you in the morning. It seems to depend on who you ask. There are a lot of different answers out there and all of them are probably based on some truth.

The University of Saskatchewan did an in-depth study on this topic and came up with some answers based on their research:

You should plug your car in if the temperature will drop below -15 C at some point during the night. You can check your weather app or the local news to see what the temperature will be.

The same study showed that after four hours you are no longer adding any benefit. Timers are very affordable and are available at Walmart, Canadian Tire and Home Hardware. You can plug your extension cord into the timer and then set it to come on four hours before you will need to start your vehicle. There are even ones now that work on wi-fi and can be controlled with an app on your smart phone.

You should get a really good-quality extension cord that will reach from your vehicle to the nearest outdoor plug allowing a generous amount of extra cord. I always like to get a cord that has a built in little LED light that glows when you plug your car into it, so you know there is power there. It just offers some peace of mind. If you don’t have this type of cord, make sure you test to make sure there is power at the plug you are using. You can do this by plugging in a hair dryer or something. If there isn’t power there then the breaker is likely turned off to that plug.

On the other end of that cord, on your car, are heaters of some kind. There is likely more than one kind. Over the years many different types of heaters have come and gone.

Cabin air space heaters were common at one time. These heaters were placed on the floor, usually in the centre of your car under the dash, and kept the inside of your vehicle warm. They are still available today but are not used very much. Technology has replaced the need for these types of heaters. Remote start systems that activate heated seats and heated steering wheels combined with better, quicker heaters now allow you to warm up your vehicle before you get in it.

There are three main heaters used today that you may have installed on your vehicle: block heaters, oil pan heaters and battery blankets.

Block heaters are the most common type and many vehicles come right from the factory with one already installed. They consist of a simple electric heating element that is put into your engine block in place of one of your engine’s core plugs and keeps your engine block warm. This type of heater will help allow your car to heat up quicker but does not assist in cold-weather starting as much as the next two types.

Oil pan heaters consist of a heating element attached to the bottom of your oil pan that keeps your engine oil warm. Warm oil will immediately circulate throughout your engine during start-up. Warmer, less viscous engine oil and less condensation of fuel on the cold metal surfaces inside the engine will assist in cold-weather starting.

Battery blankets are just as they sound: a warming blanket wrapped around your battery that keeps it insulated and warm when plugged in. This helps prevent the battery from freezing and will help start your car quickly on cold mornings.

At cold temperatures, your battery’s ability to provide sufficient power to start and run a vehicle is greatly diminished. Keeping your battery fully charged will also help. Batteries can freeze. A weak battery can start to freeze at 0 C, while a fully charged battery won’t freeze until about -60 C.

Batteries are often rated in ‘Cold-Cranking Amperage.’ This is the amount of current a battery can deliver at -18 C without dropping to a specified voltage. The higher the Cold-Cranking Amperage, the better the battery will perform in the cold.

Even at -25 C or colder you can probably still start your car without plugging it in, but you shouldn’t.

If it’s cold when you get home, you should probably plug your vehicle in right away, especially if you have it on a timer. Once you get settled in the house it’s too easy to forget about it.

Catch Driving with Jens on CHON FM Thursdays at 8:15. If you have any questions or comments you can reach out to Jens Nielsen at drivingwithjens@gmail.com, Facebook or Twitter: @drivingwithjens.