One of the big benefits of driving electric is charging up at home. While you can charge from a standard outlet, which you might have in your garage, the charge rate is often much faster from a higher power outlet. But lets discuss exactly how much faster, and if it matters at all for your situation. Do note that I am not an electrician, but the following articles I hope give you some discussion points to get the most out of your conversation with your electrician, as you plan your home charger.
There is much to consider when getting a home charger. You may already have a high power outlet in your garage. Is your laundry done in the garage? If so, there might be a high power outlet for an electric dryer that could do double duty as charging outlet. Is your panel located in or near the garage? If so, cabling costs are at a minimum, thus higher speeds can be accommodated without a significant financial outlay as high amperage cabling is expensive.
You also need to look up your EVs AC charging specifications. Most newer EVs can charge at up to 11.5 kW, while my 2018 Nissan Leaf charges at 6.6 kW, and some older first generation Leafs were limited to 3.3 kW. Whatever your EVs charging specifications are, this will determine the maximum speed AC charging you can achieve.
Also, if you have a specific charging equipment in mind, you will need to know its specifications, in particular what power-levels or current it can support. For example my 2018 Nissan Leaf came with a charging cord that supports the car’s full charging speed of 6.6 kW, while a friends car’s cord is a little slower than what the car can support. If that’s the case, and you want to use the supplied cord, this new lower power limit is what you need to communicate to your electrician.
Otherwise, perhaps its best to start with the experience related variables, and then convert that into something your electrician can work with. Most of us prefer to plug the car in at night, and have it fully charged in the morning. So, with that, two questions: What is your EVs battery pack size? And do you plan on taking advantage of lower overnight electricity tarrifs? If so, how many hours do you have on that super cheap rate.
The following table shows some common battery pack sizes (in kWh), and how long it would take to charge from 0->100%. In my case, I have a 40 kWh battery in my Leaf, and the ultra-low overnight rate here in Ontario, offers a super-cheap 3c/kWh from 11 pm to 7 am, or for 8 hours.
From the table, this suggests that a 6.6 kW charging speed is sufficient, as that charges my 2018 Leaf in a little over 6 hours. That said, the charging equipment might sit in my garage for many years, perhaps I might find myself with a newer EV, hence I might want to consider say a 60 kWh Nissan Leaf plus, or perhaps the 90 kWh Nissan Aryia. If so, perhaps 7.6 kW or 11.5 kW might be good options to consider (even though current Nissan lineup is limited to 6.6 kW and 7.4 kW respectively).
Once you have settled on a charging power, have a look at the current column, and note the expected charging current for the power level. Your electrician will need this information to source appropriate cabling and ensure that a sensible breaker is placed in your electrical panel. Another variable is approximate cabling length, longer cable runs can create lower voltages at the charger, hence your electrician might suggest a thicker cable.
Electric car adventures 