The Charging Plan

na_mobile_connectorNow that we know that we don’t have to worry about “running out of gas“, lets talk about our personal charging plan. Tesla provides the charger (shown on the right) with all of their existing cars. It allows you to plug the car into pretty much any electrical outlet available in our everyday lives. The car and the charger work together to handle this automatically so it isn’t a major headache to the driver. But how much time does a charger like this require to power an Electric Car?

Before we get into that there is one thing that you need to bear in mind when charging these type of batteries. They have the capability to charge very quickly when the batteries are near empty. However as they are charged near to their capacity the charge rate slows proportionately to prevent damage. The best analogy that I have heard is to think of charging the battery like parking cars in a parking lot. When the lot is near empty you can start parking cars hastily. As the parking lot fills up you’ll have to slow down so that you don’t start bumping cars into one another. All things considered  the numbers below are simply estimates.

110v Standard Outlet

Screen Shot 2017-03-22 at 10.56.47 PMYes, it is possible to charge off of your standard 110v outlet. The trade off is that it is very slow. The car is able to gain approximately 5 km per hour of charge. Using the estimate above this is more than enough for my wife’s typical commute to work. In fact if she utilized the outlets her work parking lot has available for vehicle block heaters, she could leave work at the end of the day fully recharged. (Fun Fact: the car will automatically  resume charging in the event of a power loss. So if there is a power outage or these plugs ins are set to cycle power off and on, the car can still utilize the power that is available).

There are two major disadvantages to using the standard 110V standard outlet for our particular daily charging needs. First, it doesn’t allow for any flexibility. If we have other things come up in our schedule (as our busy lifestyle always does), it’s simply too slow to be reliable. Secondarily, we haven’t forgot that we live in Alberta. In the winter the power flowing from the outlet would have to perform double duty. Beyond charging the batteries it would also have to power the battery heater. That can easily reduce our 5km per hour of charge to next to nil on excessively cold days.

220v 24 Amp (Dryer Plug)

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If we have access to something a little more powerful, like the typical dryer or range outlet,  the car can be charged much faster. Here we can see that the car can recover the 60 km round trip to work that my wife drives within two and half hours of charge. This works out to just over 25 km of range added per hour of charge. That allows you to completely recharge the base capacity from empty to full in just over 14 hours. This covers 99.99% of our potential use cases with the car.

220v 40 Amp (RV Plug)

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We can step that speed up a little bit if we look at installing your typical RV plug. Our 60 km daily trip is now fully recovered within an hour and half. Now the car is being charged back up at a rate near 50 kilometers an hour. This is certainly our most ideal option and provides us the greatest flexibility.

220v 80 Amp (Tesla Wall Charger)

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Tesla also offers their own branded wall charger that allows the car to be charged at even faster rates. For the current cars, it’s able to recharge as fast as 92 km of range per hour. This is certainly the most flexible option, however it’s more expensive because  you have to run the dedicated line and the wall charger itself is an additional cost.

So, we obviously have many options available to us. What makes the most sense? Well, for us we have a detached garage that currently drops below freezing in winter. As such, utilizing the existing 110v plugs won’t be enough. Since we will need to run additional power to the garage, we will be choosing a hybrid of these options. We will run 220v 40A power to a Tesla Wall Charger. This will mean that the house will have a charger dedicated to the car and there won’t be a mild inconvenience of packing the charging adapter into and out of the car on a daily basis. It will also more than handle our typical recharging needs. Yes, this will be an additional expense we will incur as we prepare for the car. A future post will detail this project as it unfolds.

If you were paying close attention you will see that the above graphics show, at a glance, how much the electricity to charge the car will cost us. My wife’s current car has a 55L tank that provides under 600 km of range. That means she is currently spending between $49 – $58 on fuel. The longer the time it takes to charge the car the more electricity is lost in the process. A faster charge time results in decreased electricity charges. Our household is currently purchasing solar offset power at a rate of $0.08665/kWh. So for 600 km of range we estimate that our electricity costs to charge her new Tesla to run the same distance will cost us between $10.75 – $15.60.

Do you have any questions that we haven’t covered yet? Any other feedback? Drop a comment below.