Keep Your Batteries Warm, Or Keep Them Charged.

by Dan · Published January 12, 2022 · Updated January 24, 2022

Winter time brings with it various challenges for vehicle owners, but let’s talk about one of the most common and most commonly overlooked ones, keeping your battery in good shape.

What’s the deal?

Your vehicle battery is the most important component to keep in good health because it is what the vehicle will rely on to start the engine, make the lights and the heating work and as a reference for all of it’s sensors and monitors. The battery typically – but not always – lives in the engine compartment and provides the electricity for the vehicle to use. Think of it as the fuel tank for the electrical bits of your car in comparison to your actual fuel tank which provides energy for your engine.

Why is it important?

Your engine can generate its own electricity with the use of a device called an alternator – but the engine must be running in order for it to work. So to start the engine, your vehicle has a starter motor which draws from the battery’s energy to start the engine spinning. The rub here is that your starter motor requires a ton of energy to do its job – for you technical types, depending on the vehicle, it can pull upwards of 600 Amps the instant it turns on. In more practical terms, 7200 Watts – the equivalent energy of 120 typical household incandescent light bulbs!

So, why is winter special?

In winter, your battery still has to deal with the problems outlined in the previous section but only worse. In the cold, your engine’s oil is thicker and therefore doesn’t flow as well through the narrow passages. Air is denser, and is therefore is harder to compress. The heat cycling of a warm engine cooling down and heating up makes condensation form and then freeze on surfaces on the interior of the engine. All these factors make it so that your starter motor requires more energy in order to turn the engine over and start it.

To make matters worse, the chemical reaction that occurs inside of the battery that creates the battery’s energy is slowed in the cold and therefore energy is harder to come by, thus compounding the problem.

How do I avoid getting stranded?

There is good news! There are two simple things you can do in order to keep your battery in good shape; keeping it warm and/or keeping it charged.

Keeping it charged is easier than it seems. Like mentioned previously, your engine automatically charges your battery by way of the alternator. This means that taking your vehicle on regular, medium length drives (20 minutes or so) is really the key here. Once you have started your car, the starter motor has drained a significant portion of the available energy in your battery, and going for a drive will allow it to recharge. Short trips (10 minutes or less) may not give the alternator enough time to fully recharge the battery leading to problems that we will cover shortly. Your battery also gets slowly drained while your vehicle is parked by what we call a parasitic draw or dark current, which is just an insidious sounding name for the energy required to keep information stored in the vehicle’s computer(s) and radio. If you don’t drive often, I would recommend you take your car out on a drive (20 minutes +) once per week or plug your car into a battery maintainer (link to some at the bottom of this article) for 24 hours every few days. Other simple tricks for people who don’t drive much or take only short trips is to take the scenic route when you eventually do go for a drive.

Keeping your battery warm is the other option but many people don’t have access to this. The problem lies in the way that your battery generates its energy – using sulfuric acid. As the energy drains from the battery, the sulfuric acid becomes less and less concentrated and more and more like plain old water. Concentrated sulfuric acid freezes at extremely low temperatures, while water freezes at 0 Celsius. Therefore, the more discharged your battery becomes, the higher the temperature at which it will freeze, and a frozen battery is a damaged battery which will not only no longer start your car, but once thawed and recharged, may never hold a charge again. To keep your battery warm, you can park your car in a heated garage or underground parking, remove it entirely and bring it indoors – which is not an easy task for many people – or install a battery warmer (links at the end of the article) and plug it in when the temperature will be low overnight.

The only real surefire way is to do both those things! You can easily combine a battery blanket and a battery maintainer onto one electrical plug and plug them both in overnight when it is going to be cold.

My car already won’t start, what now?

If your battery is low enough that your car will not start and the weather is particularly frightful (-15 Celsius and lower), there is a good chance your battery is frozen and damaged. You can use a jump starter/booster pack or a boost from another car to get your car started, but the odds of your battery being able to accept a large enough charge to become reliable again is basically nil. It may also be a good idea to invest in booster cables to leave in your trunk.

Does a battery die of old age?

Yes! Newer cars have very fancy battery management systems that greatly extend the life of a battery and so in very modern cars, it isn’t rare to see a 10 year-old battery. In older cars (model year of approximately 2010 or so and older) batteries will last between 2 and 5 years depending on how you treat them. Without going into heavy details, the more energy you extract from the battery between recharges, the more wear you are putting on your battery. If you’re one of those better-safe-than-sorry types, You can seldom go wrong by replacing a battery that is 5 years old or older – Batteries are one of those devices that are incredibly recyclable.

Can you just sum this up for me?

Batteries are incredibly important and abusing them will leave you stranded. Keep yours charged up by driving your car for a reasonable amount of time (20+ minutes) at least once per week when it is cold, or installing a battery maintainer and/or battery blanket. Replace your battery when needed or every 5 years and keep some booster cables in your trunk – and hope for a good Samaritan!

What about those links you promised?

Here you go, but please keep in mind that these are affiliate links and items you purchase with them will cost you nothing extra but may provide a commission for this website and its creator/author – me.