A Guide to Home Charging of Plug-in Cars

By · March 14, 2010

GM Charger

GM's wall-mounted 240-volt charger, which can charge the Chevrolet Volt in about three hours, meets the latest auto industry standards.

The majority of plug-in vehicle owners are expected to primarily charge their vehicles at home because of its obvious convenience. Vehicles could be charged via a standard110 volt outlet, but safety concerns—for both the vehicles and the buildings—have prompted the passing of building codes that require equipment that monitors the charging process. Plugging into a standard outlet without additional equipment is not advisable, and may void the battery warranty.

Plug-in vehicles draw a lot of power—more than any other device in the home, with the possible exception of large air conditioners. If vehicles are plugged into the same circuit as another appliance, there is the potential to blow fuses or damage equipment. Therefore, plug-in vehicle companies will require that vehicles have their own a dedicated circuit, which is installed by an electrician.

Aerovironment Charger for Nissan Leaf

Two varieties of chargers made by Aerovironment for the Nissan Leaf.

Some Assembly Required

To ensure that the batteries are provided with consistent power and are not damaged by fluctuations such as power surges, or from overcharging the batteries, special charging equipment is required. Since the world loves acronyms, this equipment goes by the name EVSE, or electric vehicle supply equipment. The EVSE setup includes a connector for plugging in the vehicle's onboard charging equipment, a charger, and a "wall box" to manage power that includes a display screen that provides information including the state (percentage) of charge.

This charging equipment will enable vehicles to be charged at multiple speeds, known as level I and II charging. (A Level III charging standard is also being developed, but the high power required is not permitted by some residential building codes, and would be cost-prohibitive for most homeowners.) Because of the timesavings, it is expected that most folks will purchase Level II charging equipment. Plug-in vehicle owners will probably be able to program charging equipment to delay charging until less-expensive off peak hours, or to specify only charging when the price of electricity falls below a set level.

Some utilities will offer smart meters that coordinates with charging equipment. The meters will be able to slow down or pause charging if the grid begins to get overwhelmed with power demand. This is considered an essential function for preventing blackouts or brownouts, which would make everyone in your neighborhood unhappy.

Charging Times

While these costs may seem hefty on top of the vehicles themselves, the federal government has established a 50 percent tax credit—up to $2,000—towards the cost of charging equipment. Solar-powered charging equipment is also now available for those who desire true emissions-free driving, and it is eligible for a separate 30 percent tax credit. A few states offer their own tax credits for plug-in vehicle charging equipment.

Getting Started

Auto manufacturers will work with their dealers to provide everything you ever needed to know about vehicle charging—and then some. They will recommend charging equipment companies, and will work with utilities to help direct you to electricians to install the equipment.

Currently charging equipment is produced by specialty companies that you probably haven't heard of, such as Coulomb Technologies, Aerovironment or Ecotality, but it is a safe bet that larger name brand companies and smaller niche players will enter the market.


· · 8 years ago

I might add that Level III charging is probably over-kill for home use. Charging in a few hours is sufficient for nearly all home charging use so there would be no reason to get an industrial electrical connection just to enable fast charging.

· · 8 years ago

The only company currently delivering J1772 EVSEs is Clipper Creek (www.clippercreek.net)

· Lindsey MacNeil (not verified) · 7 years ago

what about the charging options for people who rent - are there any companies working with complexes to accommodate?

· Anonymous (not verified) · 7 years ago

What if you move ??

· Tom (not verified) · 7 years ago

Renting &/or moving issues could likely be overcome by adding a 220V outlet relatively inexpensively near the circuit-breaker box (as used for electric laundry dryers, welders, etc.), adding a matching 220V plug to the charger, with an extra-long cord, if necessary (breakers are often in or near the garage). The charger shown at the link above (www.clippercreek.net) looks like it would easily adapt to that, instead of hard-wiring it in.

· · 7 years ago

@Tom, If you haven't already seen it, the subject of portable chargers has been much discussed in this thread:

· Katrina Kirkham (not verified) · 7 years ago

We own a small winery in Napa Valley and are 100% solar powered. I'm investigating installing a charging station for visitors to use. To my knowledge, there are no public charging stations in Napa Valley, even though it is a popular destination from San Francisco and other parts of the Bay. The average visit to our place is about an hour. I suppose we could put some bicycles out for EV owners to borrow so that they could drive to a few neighboring places, increasing their charging time to 3 hours. Do you think a charging station would be useful? How much do you think it would cost?

· · 7 years ago

@Katrina - There is an SPI and Avcon at the Premium outlets in Napa. Thanks for using solar power at your winery! So great to hear. And yes, adding a charger for visitors would be great. Even better if you had an EV to charge with it! If you install one, I'll come visit (from Davis). I promise! And I'll even bring my own bike.

· · 7 years ago

Add to me to the list. I'll visit from Berkeley in my LEAF (arriving late this month). And I'll write about the experience on PluginCars.com. Thanks.

· · 7 years ago

I'm feeling a EV PIC party comin' on. Looks like we might need a couple of chargers! (or a close second - a couple of 14-50 outlets available).

· · 7 years ago

I'm there.

· Katrina Kirkham (not verified) · 7 years ago

Thanks for the positive response! As long as we're not crushing grapes (which is only 17 days of the year from 8am - 1pm or so), we have plenty of power. Can't wait to hear from the EV Connect people about how much this will cost. I hope it is affordable. We have a hybrid car but I was drooling over the Volt this weekend and am going to hop over and have a look at the LEAF.

· · 7 years ago

Several wineries in the Napa area have Tesla charging stations already. Putting them in is both good for business and the environment.

· · 7 years ago

Hey EX - Do you have the names of those places? I wonder if they're going to add J1772s? Maybe a EV/Wine tour is in the cards.

· Sage S (not verified) · 7 years ago

On a jet Aircraft when electrecal Power is lost a small generator with a propeller pop out and -prvides power for the acft.Now if a acft can supply pwr from from a small generator why not a Eco Car.

I am no engeneer, but why can't you place a generator on each axle, and my favorate, turn the drive shaft into a generator itself to charge and run the batt and car.The result would be a Non--refueling car with no pollutuion Like I said I'm no engeneer, but if a acft can do it why can't you.

· · 7 years ago

@ Sage S.

The answer is no, you can't do it and achieve what you want. You are suggesting perpetual motion which is against the rules of reality.

Any moving vehicle can pop a prop or generator onto a moving part - and it will consume more energy than it generates. Every time. Without exception. If you have no other way to make electricity, and you need electricity, you don't sweat the loss of energy (like in your airplane example). If you are trying to make something out of nothing... you have a problem.

· Guest (not verified) · 7 years ago

I like what Sage S had to say about the pop up generator. I would think with modern technology (as it relates to gearing and fluid coupling systems for example) that something could be rigged up at the wheels (all four) to provide regenerative power to the battery while the wheels are in motion.

· · 7 years ago


I guess we have to expect this sort of thing to happen regularly. I wonder if it would be good to have some sort of FAQ that we could point to? I mean I *want* to answer politely, but this does get old in a hurry.

I'll try again. If you put a generator on the wheels (in your example) it will slow the car as it takes energy out of the system (to turn the generator) This is how regenerative braking on hybrids and EVs works - it slows the car while taking energy out of the system to charge the batteries. Now if you wish to NOT slow down - to maintain the same speed - you have to put MORE energy back into the system than you can produce with the generators (there is always loss in energy conversion). So you have a net loss of battery charge when you are powering a system that you are taking energy back out of. You're better off NOT using generators on the wheels, and just consuming the energy you need to move the vehicle without the drag of the generators.

· · 7 years ago

@Sage S

What you are advocating is called a "perpetual motion machine". Search and you will understand why it breaks fundamental laws of physics.

· Anonymous (not verified) · 7 years ago

The innovations that come out of the EV competions each year will wind up in production cars one day,.... gas turbines/ generators, integrated solar hood, trunk and roof panels, replacement emergency slide out battery packs...just to name a few. Quite a number of enthusiasts are building their own for under $10K.....wonder if this retrofit market will take off?....I'm certainly looking.

· archerpaul (not verified) · 7 years ago

Hi, I read recently that there has been talk of limiting the time of day for charging your vehicle. The article said the call was in order to reduce the overload at peak use times. Is there any truth in this?

· · 7 years ago

** Please convince me that you aren't here just to push the link to ECU mapping! You won't get much market here!

Oh, there is plenty of "talk." One has to wonder where the talk is about limiting use of AC and other large appliances that actually CREATE the peak in the first place. As far as I'm concerned everything should be on Time of Use pricing. We pay this for travel/hotel/vacation without a second though. But energy? Well, that should be the same cost no matter WHAT it costs to make! Make it expensive during the peaks and cheap during off-peak and see what happens.

In general - when left to their own devices EV drivers charge at night. That's when they're home from work and the car is parked in the garage. If the time is further incentivized there will just be that many more doing it during off-peak.

· KtG (not verified) · 7 years ago

Sonoma and Napa are our most desired destinations from Seattle! We'll be there as soon as we are able to get there from Seattle. Can't quite make it to Portland yet! Any guesses on when this will be possible?

· · 7 years ago

Great article and really nice discussion thread. Glad to hear about Napa charging available, even though I'm out on the East Coast and Napa would be a holiday retreat... Speaking of which, anyone know which car rental companies are going to be adding EV / plugins?

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