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Charging Past Failure: A Plan For More Effective Electric Vehicle Powering

Matt Conway's picture
President, Towards 50 - Percent Building Energy Savings

In 2014 Matt Conway Founded Towards 50 – Percent Building Energy Savings ( Towards 50 brings angel investors and innovators together to develop game-changing new technologies at...

  • Member since 2018
  • 15 items added with 19,653 views
  • Feb 21, 2018

A man expresses dissatisfaction with an electric car charging station on a city street.

There is a growing urgency to correctly legislate the next steps in developing electric car charging networks. In California alone, PGNE is in the process of installing over seven thousand public chargers. Similarly, Eversource in Massachusetts is moving ahead on installing four thousand stations. Both initiatives represent valuable endorsements of electric transport. Unfortunately, the chargers that most new programs plan to install are unlikely to win many converts to electric cars. Evidence of problems with the existing approaches is highlighted in the expanding number of lease buyouts that are being advertised by electric owners. Essentially, people who are desperate to get out of leases for electric cars that they find do not meet their driving needs.

Why Build a Network of Ineffective Chargers?

I recently passed 30 months and just over 32,000 miles of electric diving. I’m left with two overriding impressions:

1. The age of the internal combustion engine is over.
2. Current charge networks are a complete failure (with the exception of Tesla’s).

Full Electrics Are A Better Fit—And More Fun to Drive

As a consummate “Car Guy,” that statement rocks even my world. Electric cars are winning almost every automotive award and distinction because their power systems better meet the engineering design characteristics we like in vehicles.

My fairly mundane-looking five-door hatchback fits five comfortably, is quiet beyond imagination and yet handles better than any other car I’ve owned. It also accelerates from 0 to 60 faster than all but one model of Porsche that was on the road when I was in high school.

The Charging Disconnect

The most common hang up when it comes to buying an affordable electric is anxiety about driving range. Yes, a car with 200 or even 300-mile range would be more convenient. But in my experience, range is not the biggest problem.

The real issue is that the 6.6 kW rated chargers that have become the default standard are ridiculously slow. The bad news is, charge times are only getting worse. Second-generation electric vehicles (with ranges of 150 to 200) are likely to require more than eight hours to refill on a 6.6 kW charger. In fact, the Chevy Bolt requires over nine hours to fully charge on a 6.6 kW charger. There are many scenarios like one-car families where these charge times will not even work for home-based charging.

For city dwellers like myself, this means that only two cars can be fully charged on a single 6.6 kW charger during a 24-hour period.

First, a Serious Safety Note:
Addressing safety concerns should be step one in electric car charging plans. During each of my three winters owning an electric car I have seen chargers around New England clipped off by snowplows like blades of grass. Similarly, on a recent trip to California I saw one charger in front of a grocery store with a considerable dent. Another, in the parking lot of a business, was essentially shredded as a result of being run over.

Current charger designs do not adequately protect the public from the risk of electrocution. Crashing into or breaking charging poles off at the base represents a serious safety concern. When the most common chargers are pushed over or broken off at the base, high voltage, high amperage wires can be exposed.

Charging cords that are plugged into cars do have safety features, but there is no requirement for ground fault interruption (GFI) of the wires that feed from the grid to the charger. GFI is the type of protection common in outlets installed in kitchens and bathrooms in most homes.

Ground Fault Interruption protects people from electrocution in a fraction of a second if the safety device detects a problem. Considering that chargers are in close vicinity to moving vehicles, climbing children and people working with metal equipment like snow shovels, GFI protection of feeder circuits is essential.

The two arguments—expense and nuisance tripping—against GFI have little merit:
1. Cost concerns do not take scaled, large volume expense reductions into consideration.
2. Modern electronics greatly reduce unnecessary tripping of GFI devices.

The critical concern is to anticipate the inevitable shift in public perception that will occur following an electrocution tragedy.

Review the time required to repower one of the most efficient electric cars on a 6.6 kW charger, and it’s obvious that different chargers should be legislated for public locations. (It is important to point out that these numbers are the best-case scenario, driving during very cold or hot weather further reduces potential distances.)

Using new materials and leading-edge engineering, BMW succeeded in designing the i3 to travel further on a unit of electricity than most other electric cars. The table below details potential mileage gained from an hour of charging the i3 on a 6.6 kW charger.

Charge Time BMW i3 (6.6 kW Charger)
Charging Hours | Driving Miles Added
1                                 24
2                                 48

Two hours of charging to add less than 50 miles of driving range will not work for most people. Let’s say you drive from Boston to Manchester, New Hampshire (~52 miles) on business. As soon as you arrive, your child’s school calls and informs you that Junior is ill and needs to go home.

If you’re lucky and your car was fully charged before departing, you only need to charge for an hour before getting back on the road. If you left with less than 100% battery level, you could be looking at a 2 to 3 hour wait.

The Solution is Not a Smattering of 6.6 kW Equipment

What seems lost to all but Tesla engineers is the reality that charging electrics is very different than refilling a tank with gasoline. Charging involves balancing the need for fast repowering with the limitations of battery chemistry and the electric grid.

Installing more undersized chargers just means more places to wait and fret about being late for picking up children or missing a meeting. A growing chorus is singing the praises of DC Fast Chargers as a solution to this problem. Fast Chargers are an important part of the charging solution, but come with their own challenges.

A Place-Based Solution to a Robust Charge Network:

1. Highways: Direct Current (DC) Fast Chargers
This equipment was originally designed to meet rapid charging needs required for long trips. The idea is to enable EV owners to pull off a highway and recharge to 80 percent battery capacity in 30 minutes.

There is a growing misconception that fast chargers could be used for all charging needs. A reasonable distribution of fast chargers, especially along highways, is essential. Unfortunately, DC Fast Chargers come with three considerable constraints.

  • Regular use of this equipment degrades the life and capacity of batteries. This degradation varies based on manufacture, but regardless, it is considerable. So much so that there is an argument for legislating that fast charge use be recorded in a manner similar to an odometer. That way, used car buyers know what they are getting into on the second-hand electric car market.
  • The power needed for the systems is only available at a limited number of locations. Speedy charging necessitates huge wires that can supply volumes of power from the eclectic grid. Such large wires are not universally available.
  • Fast chargers are expensive to both purchase and operate.

2. High-Traffic Areas: High Output (10 kW and Above) 240 Volt Chargers
The best match for high-traffic areas including on-street public parking, grocery store lots and public parking garages. 240 Volt chargers are less likely to require huge power sources and constant maintenance common with DC Fast Chargers.

Equipment rated at least 10 kW is a suitable compromise between the cost for installing the equipment and miles added per-hour. Two hours of parking time at this type of charger adds 60 miles of range for most cars, even the emerging vehicles with larger batteries. The added cost over 6.6 kW equipment is minor because the upgrade is largely just a matter of larger wires from the grid connection.

3. Residential & Assigned Parking: Low output (6.6 kW) 240 Volt chargers
These units were originally designed for home-based, residential charging. This is rapidly becoming the only good fit. There are other applications where 6.6 kW chargers are acceptable, like designated parking at apartment complexes. However, with larger batteries forthcoming, 6.6 kW charge times can be a problem even for homes and apartments.

It is hard to understate the importance of legislating these chargers out of use in public parking applications. Especially with the larger battery packs that are becoming more common, charge times of over 8-hours are not acceptable. Aside from the general inconvenience, public charger spaces in cities routinely have a two or four-hour parking limit.

4. Street Parking: Light & Charge Streetlights
Introduced by BMW, Light & Charge Streetlights meet the needs of city neighborhoods. This option is the most cost-effective approach to providing overnight charge options to the large number of on-street, neighborhood parkers in most cities.

Even with energy reductions offered from upgrading old lighting technology to LEDs, it is unlikely that existing wiring and underground piping for most city street lights is adequately sized for 6.6 kW chargers. That means that the rule for pole mounted chargers is “some very limited charging is better than nothing.”

Charge Ahead

The next priority in the electric car revolution is to foster an understanding of the real world needs of the electric car driving public. Many BMW and Nissan dealers offer weekend test-drives of their great new electric cars. Legislators and planners should consider spending a weekend at the wheel of an electric before offering public funds to support outdated chargers that do not meet the needs of electric drivers.

The many benefits of electric transport are close to a reality—lets work together to make it happen.

Nathan Wilson's picture
Nathan Wilson on Feb 23, 2018

Those BEV charging complaints are understandable, however there is another side to the issue.

Most people only drive a couple dozen miles per day, thus we can expect most chargers which are combined with public parking to only supply a couple dozen miles worth of charging to a typical vehicle per day (your example of 2-4 hour parking spacing are for occasional visitors to downtown; the 9-to-5 workforce uses all-day parking at monthly rates, and likely account for the majority of parking spaces).

So I’m not sure it makes sense for all public chargers to be forced to support delivery of faster charge rates which will only be used a small fraction of the time. The market may choose to offer faster charging at some fraction of locations, but that’s different than legislation.

If the public charging infrastructure offers both 6.6kW chargers (at lower cost & more locations) and fast chargers (for a higher cost and fewer locations), then every situation has a solution, it just might not be the perfect one for every user.

Matt Conway's picture
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