When charging your EV at home
Dec 10, 2013

Concerns about charging your EV or PHEV

Ever-rising gasoline prices and toxic emissions, found belching from the tailpipes of gas-powered cars and trucks, have motivated drivers to explore their options. As a result, many drivers are placing their bets on all-electric (EV) or plug-in hybrid (PHEV) vehicles. And most, (if not all) of these drivers will rely on at-home charging to provide enough juice to get their vehicles – to there and back again. (Hey, are there any ‘Hobbit’ fans seeing this?)

So let’s look at the choice in home chargers.

Level 1 charging is just a fancy name for an ordinary standard household 120-volt outlet. You need to use the adapter provided with the vehicle. NEVER use an extension cord. If your car isn’t able to be parked close enough to a standard outlet to plug in without an extension cord, you may need to have an outlet installed.

For a fully depleted battery, a Level 1 charger will take up to 22 hours to completely charge. (i.e. – You get about 4.5 to 5 miles of range per 1 hour of charging.)

An AC Level 2 charger is a charging system that is installed and connected to a 240-volt outlet.  Installation costs may range from anywhere between $2,000 and $5,000. Costs are dependent on equipment choices and additional electrical work required.

For a fully depleted battery, a Level 2 charger can take up to 7 hours to completely charge. (i.e. – You get around 26 miles of range per 1 hour of charging.)

Now there are several things to consider when deciding on the right charger for you:

  • Should I use Level 1 charging or should I have an AC Level 2 charger installed? How much do they cost?
  • If I decide to add an AC Level 2 charger, will I need to upgrade my electrical system? Are there any state laws or building codes that I need to be aware of?
  • How do I calculate the cost of charging my EV or PHEV?
  • Would I be eligible for any tax incentives, discounts, or rebates?

AUS - When charging your EV at home

Should I use Level 1 charging or should I have an AC Level 2 charger installed?

First step is to consider your daily driving needs.  A General Motors study indicated that the average driver travels around 40 miles per day. Most all-electric vehicles currently on the market will go well beyond 40 miles on a full charge, while most PHEVs will fall below 40 miles of electric range. However, their internal combustion engine (ICE) will extend the PHEV’s total range well beyond most EVs.

The general consensus is that if your daily driving habits fall at or below 40 miles per day, then Level 1 charging overnight whilst you sleep is usually enough to completely recharge the battery. But, if you occasionally need to go on longer drives for consecutive days, you could use public charging stations on an as-needed basis instead of investing in a Level 2 charger at home.

Still, a lot of EV drivers might appreciate the added flexibility a Level 2 charger can offer them in a pinch – because we all know that life happens when we’re making other plans. Anyone who’s ever had to go on a 2 am diaper-run would definitely understand.

If I decide to add an AC Level 2 charger, will I need to upgrade my electrical system? Are there any state laws or building codes that I need to be aware of?

Installing a Level 2 charger usually requires installing a dedicated circuit and charging station at your home. EV charging equipment is considered a continuous load by the National Electric Code (NEC). (Refer to NEC Article 625.) In many areas, a site installation plan must be submitted and approved by the permitting authority prior to installation.

You will need to:

  • Conduct a home power assessment with a certified electrician.
  • Select a charger recommended by the vehicle’s manufacturer. Be sure that any charger you choose is certified to UL standards. Make sure it comes with a SAE J1772 standard connector.
  • Contact your utility. They can advise you about special electrical rates for plug-in EV charging. They also need to know about your new 240-volt charging station to maintain balance of load to your area.
  • Find a qualified installer in your area; your utility or auto dealer can help. Your installation will require an inspection and a building permit to add a new circuit. Contact your local city or county building department.
  • Use licensed and insured electricians.

How do I calculate the cost of charging my EV or PHEV?

Currently, EV efficiency is measured using MPGe which stands for miles-per-gallon equivalent. The EPA developed this measurement to provide as close to an apples-to-apples comparison of fuel efficiency as possible.

The EPA has determined that it takes 33.7 kWh of electricity to equal the energy content of one gallon of gasoline. An electric vehicle’s fuel efficiency is determined by calculating how many kilowatt-hours (kWh) it takes to provide 100 miles worth of range.

However, it’s difficult trying to calculate your actual fuel savings and electric costs using this measurement.  Green Car Reports’ John Voelcker recommends calculating the number of kilowatt hours per 100 miles, multiplied by your electric rate. Doing this will give you a much clearer understanding of your fuel savings and efficiency than the confusing MPGe rating.

To give you an example, Voelcker found that it took about 34 kWh for a 2012 Nissan Leaf to travel 100 miles.

2012 Nissan Leaf: 34 kWh x $0.12 (the U.S. average electric rate per kWh) = $4.08 to go 100 miles.

He then compared this cost to a typical 25-mpg internal combustion engine vehicle with gas costs at $4 per gallon; finding it would take 4 gallons of gasoline to travel 100 miles.

25-mpg Internal Combustion Engine Vehicle: 100 ÷ 25 miles per gallon = 4 gallons.

4 gallons x $4.00/per gallon = $16.00 to go 100 miles.

Cool, huh?

Would I be eligible for any tax incentives, discounts, or rebates?

Fuel savings aren’t the only financial benefits. You may be eligible for Federal tax credits up to $7,500 dollars. Your state may also have additional rebates and tax credits. Check Plug In America for State & Federal Incentives for EVs.

Also, be certain to contact your utility or electricity provider. The cost of charging an EV can depend greatly on where the car is being recharged and whether or not it’s being charged during peak or non-peak hours.

What kind of electricity rate plan are you on? Did you know that many electric companies offer various rate plans? Some state utilities even have rate programs specially designed for EV charging. You could be eligible for substantially lower rates. And, if you’re like most EV buyers and are going to recharge your electric vehicle batteries at home during the non-peak evening hours while you’re sleeping, you’ll enjoy lower rates for non-peak hours as well.

Tell us about your home EV charging experiences. What are the positives? Any negatives? We’d love to hear about them!

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