January 29, 2021
As winter temperatures plummet and the lockdown continues in Kingston, Ontario, your vehicle's battery may be slowly losing it's charge. Here is what you need to know to keep your battery going strong this winter.

Don’t Let Covid-19 Get Your Battery!

What is the job of the battery?

A battery stores energy to allow you to start your car. It also absorbs any excess charging that your alternator produces that your car currently does not need.

What keeps my battery charged?

Your vehicle’s alternator or charging system will charge the battery whenever the engine is running and is able to provide even more charging while you’re driving.

Why does my battery go dead if my car sits idle too long?

Cars today have many onboard computers and modules that have to keep memory and track of time.  From clocks and radio presets, to saving memory seat positions and keeping on-board theft-deterrent systems active, there are many items that continuously consume small amounts of power while the car is parked.  Gradually, after your car sits for a number of days or even weeks, these components will draw power until your battery is completely dead.

How often and how far do I need to drive to keep my battery charged up?

Cold temperatures reduce the energy reserves that a battery has available to start your car. And, in colder weather, it takes more power from your battery to turn the engine over because the oil is thicker.  Let’s assume that your battery is charged 100%.  If it’s -20C outside, the actual capacity could be reduced to 80% simply because it’s cold!  Factor in that an older battery’s energy storage capacity diminishes gradually over time, and you can easily understand that you can get into trouble if you car sits for more than a day or two without driving it!

Can a battery be damaged if it goes dead?

The simple answer to this is, YES, since most batteries can be damaged when they are repeatedly allowed to fully discharge (go dead).  And, in winter, a dead battery can actually “freeze” since the sulfuric acid inside becomes more and more like water when it goes dead. Water freezes at 0C and if your battery is basically full of water, when it freezes, it expands and can crack/damage the lead plates that normally are suspended in acid.  A damaged battery may never recharge fully and you can even damage your alternator since it will work and work to charge this bad battery until it overheats and/or wears out.

I’ve been driving my vehicle every couple of days, why is my battery still going dead?

It could be that your battery has seen better days, that you’ve left something turned on in your car or that you just haven’t been driving it often enough or long enough.  The trick with keeping your battery charged up is to drive far enough every time it’s started.  As mentioned, if it’s cold outside your battery may already be starting out with only 80% capacity available. And, a single start may draw another 20%, or more, from it’s storage of power, leaving you with only 60% or less until it’s driven. Realistically, it may take 20 to 40 minutes of steady driving to recharge your battery back up to a full charge.  So, if you regularly drive it for only 5 or 10 minutes at a time, it is unlikely that it gets charged up enough to bring it back up the level of charge you started with.

Here’s an example of a driving pattern that may be killing your battery:

  • It’s -20C outside and your battery starts out fully charged but, due to temperature, really only has an 80% capacity
  • You start the engine and now, due to the power needed get it running, you’re down to 60% capacity
  • You then drive 10 minutes to get groceries and during the drive the charging system only has a chance to recharge back up by another 10%.  So, it’s now back up to 70% capacity
  • You restart your car after getting groceries and, since it’s slightly warm from the drive there, this start only drops the capacity by 10%, bringing the current capacity back to 60%
  • You drive home for another 10 minutes and it recharges the battery by another 10%, bringing it back up to only 70%
  • You park the car – now with only 70% capacity available for the next start!
  • So, even though you’ve driven the car, the overall result is that the battery is weaker than when you started!
  • If you repeat this type of driving again and again, eventually the battery will get lower and lower in charge and possibly fail to start your car
  • Subtract the additional consumption your car uses normally when it’s parked (possibly even more time sitting due to the pandemic) and your car may be draining the battery of it’s capacity by another 5% per day
  • With this idle time and the extra the toll on the battery from the starts and stops of short trips, and it’s not hard to see how your battery can gradually get weaker and weaker until it’s time to call a tow truck!

Car Medics’ Tips To Keep Your Battery Going Strong:

Tip #1 – Regular Battery Testing

Have your battery tested at least annually to be sure it’s still good. (Car Medics tests your battery EVERY time we change your oil!)

Tip #2 – Replace It If It Fails Testing

Replace your battery when it fails testing, even though it may seem as though it’s still been starting the vehicle ok.  A battery that fails testing is harder to charge and needs to be charged more frequently, not unlike a cell phone where the battery has to be charged all the time.  This tough-to-charge battery, will make the charging system work harder and harder and could possibly cause premature failure of the alternator!!!

Tip #3 – Replace Battery When It’s Old

Replace your battery when it’s 5 years old, even if it still tests ok.  An old battery, even if it tests ok, can fail without warning and may also be causing extra workload for your charging system to keep the battery charged up.  Car Medics sells good quality Napa Batteries that last!

Tip #4 – Drive Regularly

Drive your vehicle at least every 3 days, ensuring that it is driven for at least 20 minutes after each start.

Tip #5 – Drive Long Enough

If you’re starting it for a very short journey, have someone go with you so you can leave them in the car and leave the car running while you run inside somewhere to make a quick errand. This will save the second start and if it stays running, the battery will charge up even more!

Tip #6 – Extend Short Trips

If you have no option to take someone with you and leave it running on a short trip, add an extra drive on the end of it before you park it back at home again.  It’s always nice to get out of the house during the pandemic!

Tip #7 – Turn Off Car Accessories When Parked

Turn off all accessories when you park your car such as heated seats, blower motors and radio so that you save all the battery power you have available to START the car.  Once the car is running, you can turn on all the items you want.

If you have any questions or would like your battery tested, give Car Medics a call or send us an email and we’ll keep you and your car mobile this winter!

Car Medics has been in business for over 27 years, serving Kingston and surrounding areas. We are experts at all aspects of automobile repair, including diagnostics and charging systems.  We also have great advice!

“We Are Always Accepting New Patients”

Two locations to serve you better:

Call 613-547-8473 for Kingston location

Call 613-546-6766 for Glenburnie location

Stay safe and healthy!



Monday-Friday: 8am - 5pm



Need your car serviced?